The Garden Professors™

Tuning up for Pruning Up–Care, Maintenance and Utilization of Hand Pruning Tools

A. J. Downer

Fall is passing into winter and the bare sticks in my deciduous fruit orchard are calling to my annual fruit tree pruning chores. I can prune my entire orchard with very few tools: a good pair of bypass clippers, a similar set of loppers

Illustration 1. Tri-edge saw blades are made from stainless steel and are not easily sharpened. When dull or bent they should be replaced.

(optional) and a high quality “razor” or “tri edge” saw. Most hand tools require some maintenance especially the clippers and loppers. Clippers are easily sharpened but modern saw blades can not be sharpened by gardeners. I usually just buy a new saw, replacing the old one when blade eventually dulls or bends from over zealous use (illustration 1).

Illustration 2. To sharpen bypass clipper blades follow the angle of the bevel. Do not sharpen the flat side of the blade

Before using your pruning tools inspect them for signs of damage. Blades should be sharp and straight. Loppers should have their rubber “bumpers” intact otherwise your knuckles will be smashed after exerting force on a difficult branch. Sharp tools offer less resistance and actually decrease injury to users. One exception here is with the modern “tri-edge” or “razor” saws. These saws can cut so quickly that you may pass through the branch you are cutting and continue on to some part of your anatomy quickly ripping your flesh open. I have suffered more cuts (some serious) from these saws than from any other gardening activity (although I was recently impaled by a frog metal art sculpture!). They should be used with careful precision, not with the wild abandon and pruning fervor of the craven academic desperate for real world pruning experiences. A thick long sleeved shirt and gloves will also help prevent cuts from hand pruning equipment.

Bypass clippers are so termed because the blade passes by the hook. To sharpen these, find the bevel on the edge of the clippers and align a small file to the same angle of this bevel, and file the bevel until you can feel the sharpness with your finger (Illustration 2). Never sharpen the back side of the bevel—this will create a gap, and every time you cut, a flap of tissue will remain. Back bevel sharpened clippers will require blade replacement or grinding until the back bevel is gone. The hook does not require sharpening, do not attempt to file it. Repeat this process with lopper blades.

When you are done pruning for the day, wipe the blades of your clippers and loppers with an oil soaked rag or apply a few drops of oil and rub it into the blade. Most modern saws blades are made from stainless steel and require no oil protection.

As a Cooperative Extension Advisor, one of the most common questions I receive is: “Should I sanitize my clippers between cuts or between uses on various plants?”. Indeed, many publications, extension leaflets, gardening columns, and other sources make broad recommendations to sanitize clippers after every cut. Some articles even compare various products for their killing efficacy. Blind recommendations are often made to sanitize clippers when the pathogen is not known or specified. It is not necessary to sanitize your clippers when pruning most garden plants and fruit trees. There are a few pathogens that are spread by moving plant debris, but published evidence that they are spread by hand pruning equipment (especially clippers) is nil. One exception is palm wilt caused by Fusarium oxysporum f.sp. canariensis which is easily spread by saws. Some of the canker fungi caused by Botryosphaeria can also be spread by pruning equipment. With many of these pathogens, a wound is required for infection so it may not be that the clippers are spreading disease so much as providing an entry point (infection court) so that pathogens have a way to enter.

If diseases are present in or near the plant already, sterilizing pruning equipment will simply provide a clean entry port for the pathogen—infection can still follow after the cut is made with a sanitized tool.

In my garden, I never sanitize clippers between cuts. However, conditions vary across the US, and in some places rain, humidity, and temperature are more favorable for disease development. If you have concern about spreading pathogens, prune during the dormant season, when the likelihood of pathogen activity is lowest. Apply dormant sprays containing copper to limit the onset of new fungal diseases that may enter pruning wounds. If you still feel you need to protect wounds from dirty clippers I like to use the flame from a plumber’s torch to sanitize. A few seconds along the cutting edge front and back kills all pathogens (Illustration 3). The process is similar for a saw but efficacy is increased if the saw gullets are wiped clean with a cloth and then the flame applied. The only time I take these measures is when I know I am working with plants that can be inoculated by pruning (which is rare).

Illustration 3. A plumber’s torch will rapidly sanitize saws and blades when pathogens are present in plant tissues.

When pruning garden plants, there are a plethora of recommendations on how to make cuts. Rose experts have extolled the virtues of an angled cut so water runs away quickly, flush cuts used to be recommended by arborists as the highest quality cut. These examples are without research foundation. Cuts on woody plants should made to create the most circular exposure that leaves the smallest surface area possible. We abandoned flush cuts many years back because they cut into protective zones that limit decay in trees. Some gardeners feel compelled to cover their cuts with a pruning paint and there is a similar paucity of research to support this practice. Leave pruning wounds unpainted.

The Myth, the Legend, the Parasite: Romance, Lore, and Science beneath the Mistletoe

As we hurdle ever closer to the holidays and the end of the year, there’s lots of plants we could talk about – amaryllis, poinsettias (and the abuse thereof with glitter and paint), whether or not your cactus celebrates Thanksgiving, Christmas, Easter or is agnostic, and on and on. Each of these plants have an interesting history and connection to the holidays, but today we’re going to be a little more naughty…but nice. We’re going to talk about mistletoe.

Now, mistletoe is one of those holiday plants that you don’t really want growing in your own garden. That’s because, even though it is a symbol of love and even peace, it truly is a parasite … and poisonous. It has been celebrated and even worshipped for centuries, and still has a “naughty but nice” place in holiday celebrations.

Burl Ives, as the loveable, banjo-playing, umbrella-toting and story-narrating snowman in the classic “Rudolph the Red-Nosed Reindeer” claymation cartoon tells us that one of the secrets to a “Holly Jolly Christmas” is the “mistletoe hung where you can see.” But where does this tradition of giving someone an innocent (or not-so-innocent) peck on the cheek whenever you find yourselves beneath the mistletoe come from? And just what is mistletoe anyway?

While mistletoe specialists need mistletoe, the reverse does not holdâmistletoe in many regions is dispersed solely by dietary generalists. — Distribution of mistletoe (and mistletoe specialist birds). Source: Mistletoe Seed Dispersal. Watson, D.M.

There are around 1500 species of mistletoe around the world, mainly in tropical and warmer climates, distributed on every continent except Antarctica. In North America, the majority of mistletoe grows in the warmer southern states and Mexico, but some species can be found in the northern US and Canada. A wide variety of birds feed on the berries of mistletoe and thus disperse seeds. These birds include generalists who opportunistically feed on mistletoe, and specialists who rely on the berries as a major food source.

Mistletoe Haustoria from from Julius Sachs’ 1887 Lectures on Plant Physiology. Source: The Mistletoe Pages

First, we’ll cover the not-so-romantic bits of this little plant. Mistletoe is a parasitic plant that grows in a variety of tree species by sinking root-like structures called haustoria into the branches of its host trees to obtain nutrients and nourishment. It provides nothing in return to the tree, which is why it is considered a parasite.

A heavy mistletoe infestation. Source: Pixabay

Mistletoe grows and spreads relatively slowly, so it typically does not pose an immediate risk to most trees. While a few small colonies of mistletoe may not cause problems, trees with heavy infestations of mistletoe could have reduced vigor, stunting, or susceptibility to other issues like disease, drought, and heat. So be on the lookout for mistletoe in your trees and monitor it’s progression.

This little plant does have a long and storied history — from Norse mythology, to the Druids, and then finally European Christmas celebrations. Perhaps one of the most interesting things about the plant is the name. While there are varying sources for the name, the most generally accepted (and funniest) origin is German “mist” (dung) and “tang” (branch). A rough translation, then, would be “poop on a stick,” which comes from the fact that the plants are spread from tree to tree through seeds in bird droppings.

“Baldur’s Death” by Christoffer Wilhelm Eckersberg (1817)

In Norse mythology, the goddess Frigga (or Fricka for fans of Wagner’s operas) was an overprotective mother who made every object on Earth promise not to hurt her son, Baldr. She, of course, overlooked mistletoe because it was too small and young to do any harm. Finding this out, the trickster god Loki made a spear from mistletoe and gave it to Baldr’s blind brother Hod and tricked him into throwing it at Baldr (it was apparently a pastime to bounce objects off of Baldr, since he couldn’t be hurt).

Baldr, of course, died and Frigga was devastated. The white berries of the mistletoe are said to represent her tears, and as a memorial to her son she declared that the plant should represent love and that no harm should befall anyone standing beneath its branches.

The ancient Druids also held mistletoe in high esteem, so high that it could almost be called worship. During winter solstice celebrations, the Druids would harvest mistletoe from oak trees (which is rare — oak is not a common tree to see mistletoe in) using a golden sickle. The sprigs of mistletoe, which were not allowed to touch the ground, would then be distributed for people to hang above their doorways to ward off evil spirits.

While the collecting and displaying of mistletoe was likely incorporated into celebrations when Christmas became widespread in Europe in the third century, we don’t really see mention of it used specifically as a Christmas decoration until the 17th century. Custom dictates that mistletoe be hung in the home on Christmas Eve to protect the home, where it can stay until the next Christmas Eve or be removed on Candlemas (which is Feb. 2). The custom of kissing beneath the parasitic plant isn’t seen as part of the celebration until a century later.

Washington Irving, who more or less reinvigorated the celebration of Christmas in the United States in his day and whose writings still define the idyllic American Christmas celebration, reminisced quite humorously about mistletoe and Christmas from his travels to England. He wrote:

“Here were kept up the old games … [and] the Yule log and Christmas candle were regularly burnt, and the mistletoe with its white berries hung up, to the imminent peril of all the pretty housemaids.”

Whether or not your housemaids will be in peril, the hanging of the mistletoe can be a fun Christmas tradition. Look for it at garden centers and Christmas tree lots this season. Or maybe you can find some growing wild and harvest it for your own decor. However, I would recommend not getting it out of the trees the “old Southern way” — shooting it out with a shotgun.

Sources:

Tainter, F.H. (2002). What Does Mistletoe Have To Do With Christmas? APSnet Features. Online. doi: 10.1094/APSnetFeature-2002-1202
Briggs, J. (2000). What is Mistletoe? The Mistletoe Pages – Biology. Online. http://mistletoe.org.uk/homewp/
Watson, DM. (n.d.) (accessed). Mistletoe Seed Disperal [Blog Post]. Retrieved from https://ecosystemunraveller.com/connectivity/ecology-of-parasitic-plants/mistletoe-seed-dispersal/
Norse Mythology for Smart People. (nd) The Death of Baldur. Retrieved from https://norse-mythology.org/tales/the-death-of-baldur/

What’s wrong with my plant? You’re not going to find pat answers.

As many of you know, the Garden Professors host a Facebook group dedicated to the discussion of science-based practices for gardens and landscapes. (Side note – if you haven’t joined us please do!) Recently we’ve had a spate of “what’s wrong with my plant” posts, usually focusing on some leaf issue and little other information. And far too often an eager group member will jump in with a fertilizer recommendation. So today’s blog post has two objectives: explaining why you can’t reliably diagnose problems from a picture of suffering leaves and why blanket fertilizer recommendations should be avoided.

To illustrate the problem with armchair diagnosis, consider this photo below.

Interveinal chlorosis in *Rhododendron*.

Now there are two ways to ask a question here: the first is “what’s wrong with these leaves” and the second is “what’s wrong with my plant.” We can easily answer the first one: there is nutrient deficiency in the leaves, most probably iron or manganese. But that does NOT mean there is a deficiency in the soil. So we can’t address “what’s wrong with my plant” because we don’t have enough information.

How can we determine what’s wrong? My first question to the poster is invariably “have you had a soil test?” Soil test results will indicate whether the element in question is actually deficient, and will provide levels of other nutrients that could interfere with root uptake. If there’s no deficiency of the nutrient in question, then adding fertilizer is not going to help! And adding fertilizer unnecessarily can create further soil nutrient imbalances and contribute to environmental pollution.

Once we have the soil test results, we can then begin to address “what’s wrong with my plant.” But not from the original picture. (If you are curious about what else could be causing this problem, check out this blog post from 2011.)

Let’s try another. Consider the leaves in this photo:

We now know to ask “what’s wrong with these leaves?” Ignore for now the deficiencies in the older leaves and look at the size of youngest ones compared to the older. The answer is fairly straightforward here: there was too little water available when the newly emerging leaves were expanding. Leaf expansion depends on turgor pressure – the higher the turgor pressure, the larger the leaves get. Once expansion stops, protective plant biochemicals are laid down which prevent further expansion. By comparing the youngest leaves to the leaves from previous years, you can see that they are significantly smaller. But why?

Again, we need more information before we can answer “what’s wrong with my plant.” Was there too little available soil water during leaf expansion? It’s possible, but this example is from western Washington State, a climatic region with wet springs. Most likely there is an issue with the roots. My first question with these cases is “can you easily move the plant in the ground?” This is my “wiggle test” – a way to determine if roots are established. In this case – and in nearly every case like this that I’ve seen personally – the roots are NOT established. Often this is because the plant (1) was not bare-rooted at planting and/or (2) was planted too deeply. Without decent root establishment there is not enough water uptake to support full turgor in expanding leaves.

It may be quick and easy, but “pop and drop” is not a good planting method.

Lack of an established root system also account for the interveinal chlorosis you can see in the oldest leaves. These leaves are fully expanded, probably because the plant was still at the nursery when these leaves emerged. But their color is off. A root system that doesn’t supply sufficient water for leaf expansion is by default not going to provide sufficient nutrients, either. Adding fertilizer to this plant is not going to help! It needs to be dug up and replanted correctly or replaced. It is never going to thrive under the current conditions.

Armchair diagnosis can be accurate and fun if you follow a set of guidelines to extract more information. But simply recommending a fertilizer based on leaf appearance is neither science-based nor environmentally responsible.

No. Just….no.

“Fun-guy” in your Mulch

By Jim Downer

As many avid GP readers are aware, mulches are a common horticultural tool that help gardeners maintain soil moisture, nutrient content, weed suppression and assist in disease prevention. The best mulch is made from chipped tree trimmings wastes and has a large wood content. Coarse “arborist chips” mulch is fast becoming one of the most frequently sought after mulches for residential landscapes. It is very effective and contributes to significant soil improvements over time. As chip mulches decompose, the fruiting bodies of fungi are often seen growing up through mulch. Sometimes, as gardeners work in previously mulched beds, they see mycelium or cordons (rhizomorphs) of mulch fungi growing through the mulch. Some gardeners are not fond of finding mushrooms growing in their mulch and have termed these as “nuisance fungi”. There have even been extension leaflets on nuisance fungi and how to rid them from your garden!! Fungi are a natural part of mulch breakdown and their presence in mulches is desirable!

*Phanaerochaete chrysorhiza* invading *Eucalyptus globulus* mulch

The first encounter many gardeners have with mulch fungi is when they see “mold” growing in the chips or at the interface of mulch and soil. Mold gets a bad rap with many homeowners when they find it after water damage in their house, so perhaps they assume it is also bad for their gardens. Mold abatement in homes has become a specialized industry, and while the spores of some fungi can be human pathogens, fungi are not to be feared in gardens unless your immune system is damaged or otherwise compromised. Unlike houses, gardens are a good place for fungi to grow and thrive.

Fungi absorb water and nutrients from their hyphae which grow into their food (mulch particles). The absorptive lifestyle of fungi is unique. Since fungi have no internal digestive systems, they rely on excreting enzymes outside their bodies and into their food which breaks down the substrate so they can absorb it. By doing so, they also release minerals, sugars, amino acids and many other compounds for other microbes and plants to utilize. Fungi are mostly saprophytes or decomposers, and their role is to release organic nutrients to soil so they can be recycled. This is why mulches are so beneficial to woody plants. Without fungi, forest litter would pile up largely undecomposed because bacteria and other microbes are less efficient in breaking down cellulose. Some fungi are mutualistic partners with woody plant roots. Ectomycorrhizal (EM) fungi rely on interactions between trees themselves and the litter or mulch layers under trees. Fruiting bodies of EM fungi may appear as mushrooms or puff balls in or next to mulches.

*Lepiota* spp. an ectomycorrhizal species

*Amanita muscari* , another ectomycorrhizal species. Just don’t eat it.

Sometimes fruiting bodies (mushrooms) push through mulch, but are not the result of mulch presence. Pathogens such as Armillaria mellea (oak root fungus) can form through mulch layers or turfgrass, but they are fruiting off the dead roots of their tree host. Similarly, the inky cap mushrooms (Coprinus spp.) often grow saprophytically on dead roots (they are not the cause of root death) and will push through litter layers. Coprinus are good indicators that a tree has dead roots. Coprinus is not a plant pathogen, and mulch does not increase prevalence of pathogens in landscapes. As we have discussed many times in the blog, mulches are unlikely to spread or support plant pathogenic fungi.

*Coprinus* spp., which feed on dead roots

Another way to view the role of fungi is the chemistry that they facilitate in soil. Mulch is organic matter, which has a high concentration of carbon. Carbon is transformed from a solid form into a gas – carbon dioxide – through the action of microbes (mostly fungi). So oxidation of carbon is driven by fungi growing through their substrate (forest litter in forests or mulch in gardens). In mulching systems this is a slow process taking a few years. In composting systems it is rapid, taking months with the added energy of mechanical turning etc. Slow decomposition of organic matter is useful, as the benefits of mulch in suppressing weeds, slowing evaporation from soils etc. are maintained over time. Slowly oxidizing carbon means that it will be around longer, creating less greenhouse gasses than in the composting process.

In publications that recommend ways for “dealing with nuisance fungi” it is suggested to let mulch dry out, which stops the action of the fungi. This is one of the most harmful things that can be done for active mulch zones. Killing the fungi in mulch also stops their oxidation of carbon, subsequent nutrient release and support for the high microbial activity in mulches that benefit both plants and disease suppressing fungi that plants rely upon to maintain their health. While fungi can reactivate when dry mulches are moistened, their biomass is damaged by severe drought which also injures plant roots as well.

All good things come to an end or as our physics friends say, “Entropy increases!!” So as labile (easily metabolized) carbon is used up in fresh mulches, fungi go into spore bearing or reproductive phases and begin to make fruiting bodies. As long as there is labile carbon, fungi will thrive and grow mycelium and hyphae into their food. When carbon is being used up (or when there is sufficient mycelium), fruiting bodies start to form. To maintain these processes, it is important to add fresh mulch over the old decaying mulch. Once or twice a year depending on temperature and moisture levels. Along the way, some mulch may develop fungal fruiting bodies. Fruiting bodies may resemble mushrooms, puff balls, earth stars, bird nest fungi, or simply resemble paint that has been splashed on the wood chips. They are only trying to survive by developing spores which will later spread onto fresh mulch materials. Most mulch fungi have very ephemeral fruiting bodies, so even if they are seen to be a “nuisance”, they will only be around for a very short time before they also decompose and become part of the remaining mulch layer or soil.

*Ceraciomyces tessulatus*, a paint-like fungus

One very common group of organisms seen in mulch and mistaken for fungi are the slime molds. They are not related to fungi, but do develop spores and have a mobile (plasmodium) phase where they can be seen to slowly move from one spot to another. Eventually, when the plasmodial stage is done feeding, the sporangial phase is made and they turn into spores. The most commonly encountered slime mold in mulch beds is the dog barf fungus, a slime mold called Fuligo spetica. Fuligo is dramatic because it can appear overnight and is large (a patch of the sporangium can be several inches across). When kicked, Fuligo bursts into dark spores that will fly up into the air. Slime molds are also saprophytes and live on the decomposing organic matter in mulch. They pose no threat to humans or garden plants.

Yellow slime mold, aka dog vomit fungus (photo from Wikimedia)

Fungi in the mulch are a good thing and indicate that moisture, temperature and organic matter are at the correct levels for high microbial activity! This is what creates a healthy soil and ensures healthy garden plantings.

Thanksgiving: A celebration of the native plants and indigenous crops that grace the table

Native vs. non-native – that a subject that is brought up frequently on our forums and one we have to discuss at length. However, I thought I’d take it from a different direction this week, a little diversion if you will, seeing as we are just a week away from our American celebration of Thanksgiving that centers around food – much of it native to the United States.

It is a holiday that is quintessentially American (or North American, since our Canadian friends also have their own Thanksgiving). A commemoration of not only the arrival and survival of the pilgrims in Plymouth in 1621, but of our thankfulness for what we have. It is a time for us to gather with family or friends and reflect upon our blessings.

While, much to my chagrin (and that of many others), Thanksgiving seems to have been swallowed up by the Christmas “season” and you can even go shopping for more stuff (an abomination, for sure) on a day when we are supposed to be thankful for what we have, it is still a day celebrated by many.

Turkey, dressing, potatoes, fresh bread rolls and pumpkin pie are the traditional fare for the celebration these days, but they are a far cry from what the original feast shared by the pilgrims and American Indians would have featured.

Historians agree that, while the feast was probably meat-heavy, turkey was probably not on the menu. It just wasn’t as popular a food item as it is today. Most agree that the original feast featured venison, with some waterfowl (goose or duck) and seafood (shellfish like oysters are a definite, maybe even eels or other shellfish).

I don’t think I’m alone in saying that I like the side dishes better than I like the actual turkey. There’s the dressing (or stuffing, depending on your preparation or colloquial terminology), mashed potatoes, sweet potatoes, and my aunt’s seven-layer salad that’s usually more mayo and bacon bits than vegetation.

The produce dishes at the first Thanksgiving would have been vastly different than the modern day smörgåsbord that we prepare. Experts agree that the majority of dishes would have been from native plants and indigenous crops grown by the local tribes, with a few ingredients showing up from the pilgrims’ gardens.

First off, the absence of wheat flour, sweetener and flour would mean the lack of the classic dessert…pumpkin pie. It is hard to imagine a lack of pumpkin while we live in a time in which we are surrounded by pumpkin spice everything (though mostly artificially flavored).

Sugar would have been too expensive to purchase for the voyage, and other sweeteners would have been limited to maple or other tree syrups. (Colonists had not yet brought over the honey bee, which is a European immigrant itself).

This is not to say that there wasn’t squash. There were squashes, including pumpkins, as part of the native diet at the time having spread from their origins in Mexico and Central America . They were likely included in the feast, but either boiled or roasted, and unsweetened.

Beans would have probably been one of the dishes, as well. The Natives Americans ate beans both in dry and green form, but at a fall feast, the beans were likely the dried variety and cooked into a soup or stew. Corn was also a feature of the first Thanksgiving, but not sweet corn (which didn’t make an appearance until much later). The corn would have been a flint type (similar to popcorn) that would have been cooked into porridge or used as a bread.

Native tree nuts, such as walnuts, chestnuts and beech nuts could have also been used in the preparation of dishes. There isn’t any written record of the native cranberry or blueberry being used, either, but they would have been abundant in the area. They likely wouldn’t have caught on in popularity until sweeteners such as sugar from Europe or honey was available to dull their acidic bite, but the dried fruits could have been used in preparations of some of the meat. If there was a salad, watercress could have been used if an early frost hadn’t wiped it out.

The pilgrims had brought with them from Europe various seeds, including herbs and onions, that could have been used to flavor some of the dishes. They may have also brought things like turnips and carrots that could have been available for the first feast (though there isn’t any direct written proof).

One native food that would have most likely been on the first Thanksgiving table is the sunchoke (Helianthus tuberosus), or Jerusalem artichoke. Fallen out of favor for some time, the sunchoke is making its return to many gardens.

Image result for jerusalem artichoke — Jerusalem artichoke/sunchoke flower *Wikimedia Commons*

A true native food source, the sunchoke is the tuberous root of a species of sunflower (you may even see them growing on roadsides in the fall). The rhizome is roasted or boiled and has a nutty, starchy, potato-like texture and flavor. If you want to grow it, just remember that it is a perennial that will readily spread in the garden. These would have been the closest things to a potato dish the first celebrants would have eaten — we were still a long way away from bringing the potato from South America and the sweet potato from the Caribbean. (Botanist’s note: What we eat are sweet potatoes [Ipomea batatas], not yams [Dioscorea sp.], despite the insistence of canning companies. They aren’t even in the same family.)

So as you sit down for your Thanksgiving feast, be thankful for the blessings in your life and for the leaps and bounds our food options have improved over the past 400 years. Also be thankful for butter, flour, and sugar so you can have your pumpkin pie.

Native vs. nonnative – can’t we all just get along?

Probably the most contentious gardening topic I deal with online is the native vs. nonnative plant debate. This, unfortunately, is a debate that is more based in emotion than science, and I don’t intend to stir that pot again. We’ve discussed it on this blog before (you can find a list of them here), and I’ve published both a literature review and a fact sheet on the science relevant to tree and shrub selection. What I want to do in this post is compare two research papers, both in peer-reviewed journals, that come up with dramatically different conclusions.

The first has been getting a lot of publicity on the web and in social media. It was published just two days ago, but because of widespread PR prior to release it appears over 37,000 times in a Google search. The title – “Nonnative plants reduce population growth of an insectivorous bird” – and much of the prerelease publicity about the article spells doom and gloom. It’s a message that gets traction.

The second was published a year earlier and is entitled “Native birds exploit leaf-mining moth larvae using a new North American host, non-native Lonicera maackii.” It appears 194 times in a Google search, even though it’s been available for over a year.

The reason I’m singling out these two articles is they have completely different messages – and one of them is not being heard as loudly as the other. The first focuses on a single bird species, the Carolina chickadee (Poecile carolinensis) and its diet in urban landscapes. Their conclusion: “…properties landscaped with nonnative plants function as populations sinks for insectivorous birds.” Thus, any gardener who happens to use introduced ornamental plants in their landscape is made to feel guilty for starving their insect-eating birds. (As an aside with my manuscript reviewer hat on – this statement has no business being in an abstract as it overextrapolates the research on one species to include ALL insectivorous birds.)

Carolina chickadee (Poecile carolinensis)

Black-capped chickadee (Poecile atricapillus)

The second article has a different focus. It reports the feeding of black-capped chickadees (Poecile atricapillus) on the larvae of a leaf-mining moth (Phyllonorycter emberizaepenella). While leaf miners are common food items for chickadees, the point of this article was to document the host of the leaf-miner – a nonnative and particularly invasive species of honeysuckle (Lonicera maackii).

Honeysuckle leaf miner (Phyllonorycter emberizaepenella)

Chickadees as a group are particularly adept at finding and consuming leaf miners, whose tunnels normally protect them from insectivorous birds. Chickadees move along branches,“examining leaves both above and below them; the chickadees sometimes scanned by hanging upside-down.” This makes it easier to find and extract leaf-miners, as the underside of the leaf is easier to tear open than the surface. And in fact this behavior is reflected among other species of chickadee and leaf-miner: “Similarly, in 15 years of study, Connor et al. (1999) never observed species other than Carolina chickadees (Poecile carolinensis) feeding on the larvae of the gracillarid Cameraria hamadryadella [oak leaf miner].” While these are not the same species of leaf miner studied in this paper, the point is that chickadees eat leaf-mining insects. And leaf-miners can obviously adapt to new food sources, including introduced plants. This is basic ecological science.

Oak leaf miner (Cameraria hamadryadella)

Neither Craves’s article (the second of these two articles) nor that by Connor et al. (cited within Craves’s article) are cited by Narango et al. (2018 – the first article), even though both are certainly pertinent to the topic. But they don’t fit the narrative – which is that introduced plants are not good food sources for the insects that chickadees eat. So they are left out of the discussion, which by default is now biased – not objective. Not science-based.

And I don’t have a good answer to the obvious question – which is why we continue to demonize noninvasive, introduced plants in the absence of a robust body of evidence supporting that view.

Grow Garlic – Keep the Neighborhood Vampires at Bay

While most of those gardening tasks are coming to an end, in most parts of the US it’s time to think about planting a few things in the veggie garden to bring a flavorful bounty next year – garlic (and a few related alliums).

I often reference Halloween and vampires when I talk about garlic, not just because traditional lore says that garlic repels vampires, but because it is a good reminder of when to plant garlic in the garden. October is the prime time for adding the alluring allium to the garden. You can also remember that you plant garlic during the same period that you plant spring flowering bulbs.

Why do vampires hate garlic?

Yes. Vampires are fictional (unless someone finds some empirical evidence of their existence, since you can’t prove a negative 😉 ). These bloodsucking creatures of folklore may actually have a basis in fact that could explain their aversion to garlic. Way back when people didn’t have science to understand things, they often invented explanation for things that were supernatural. Sometimes these explanations may have actually had some truth to them.

In this case, the symptoms of vampiricism could have evolved from the symptoms of porphyria – a set of rare disorders of hemoglobin (there’s the connection between vampires and blood). Symptoms of porphyria include shrunken gums (that could make teeth look like long fangs), painful sensitivity to sunlight, and….and averse reaction to garlic. The reaction comes from the effect of garlic on the blood – it can stimulate red blood cell turn over and increase blood flow, both of which can exacerbate symptoms of porphyria and cause acute, painful attacks. There’s also an allegorical connection – vampirism was considered a disease (or represented the spread of disease in some literary cases) that was spread by a causal agent and garlic was seen as a curative for disease (it does have some antibacterial properties). Note: other possible symptoms of porphyria can be excessive hair growth in random areas of the body, which gives it a connection to lore around lycanthropy.

On to the gardening

Now that we’ve covered some trivial, albeit interesting, info lets get on with the gardening!

While many people are accustomed to the single variety available in grocery stores, there are several different types of garlic that all have different flavor characteristics. These types can be classed in two categories; hardneck garlic has a hardened central stem when it dries, and softneck garlics remain soft and pliable. Softneck varieties are the ones that lend themselves to being braided into those hanging garlic braids. Softneck varieties are also longer-storing than hardneck varieties.

It can be tough to find garlic in local garden centers to plant. Those that do carry garlic, often carry it at the wrong time of year for planting when it is shipped in on the spring garden displays. If you don’t have friends to share their garlic with you, or a local farmer to buy some from, you are going to have to go the mail order (or online order) route.

Once you have your garlic bulbs, split them up into cloves, being sure that you have a piece of the basal plate (the part that holds them all together) on the clove. This one clove will turn into a whole bulb over the growing season.

Plant the cloves tip up about 4 to 6 inches apart and about 2 inches deep in loose, organic soil. Mulch after planting with about one inch of straw or shredded newspaper.

Garlic is a relatively heavy feeder, so it would benefit from a good balanced fertilizer treatment with nitrogen after it is established. You can also plant them in the garden where you grew beans over the summer – the bacteria that colonized bean roots adds nitrogen to the soil.

After that, just be patient. It may pop up before winter if the weather is mild, but don’t worry – it can survive even if a freeze kills the growth back to the ground. Garlic requires little maintenance, and only requires water if the weather turns very dry. Harvest it once the leaves start to die in mid-summer (around July, unless it is an early-maturing variety). Be sure to save some to plant next year and store the rest for use in the kitchen.

Aside from garlic, there are some other odoriferous onion relatives you can plant this time of year like shallots and perennial onions in the vegetable garden or edible landscape.

Shallots have a mild onion flavor and are great because they form cloves like garlic (meaning you don’t have to cut up a whole bulb if you just need a little bit) and store well. The beauty of shallots is that they can also be planted in really early spring — they are a multi-seasonal crop. You can also start them from seeds in the spring.

Shallots are technically perennials, as they will grow over many years if left undisturbed. However, to harvest them, you have to dig them up so they are usually grown as annuals. Once you dig them up, use the larger bulbs for cooking and save the smaller ones for replanting.

Multiplier onions, sometimes called “potato onions” are another fall-planted perennial. These plants produce clusters of bulbs (hence the name “multiplier”) that are harvested in the early summer for bulb onions.

One of the benefits of these and other perennial onions is that you can harvest the green blades of the plant for use as green onions or scallions throughout most of the winter and spring.

Egyptian walking onions are another perennial that can be harvested either for its bulb or as a green onion. The name comes from the bulbils that form at the top of the flower stalk. When they mature, they get heavy enough for the stalk to collapse and fall over, creating a new bunch of onions away from the mother plant. You can allow them to do this to fill in an area, though most people limit it by harvesting the bulbils before they fall.

There are also perennial leeks that have a flavor similar to leeks and can be harvested as green leeks through the winter or dug up as small, tender leeks in the spring.

If you love growing perennial vegetables that add flavor to just about any dish, give these tasty plants a try. They’re really simple to grow and can keep your garden and your kitchen full of fun and flavors for years to come.

A quick primer on types of garlic

Hardneck Varieties

Purple Stripe — bulbs have purple on the outside. Some of the tastier garlics that become deliciously sweet when roasted.
Porcelain — popular gourmet variety. Usually has a more robust and spicy flavor. Bulbs are typically large and have large cloves.
Rocambole — Rich, complex flavors popular with chefs. Their scapes (edible blooms) form a double loop. They do not do well where winters are warm.
Asiatic/Turban — Do not store for long periods. Mature earlier in the season (late spring as opposed to summer) than other types. Flavors are usually strong and hot.
Creole — Attractive red color. Performs well where winters are warmer. The flavor is similar to (though milder than) Asiatic/Turban Varieties.

Softneck Varieties

Artichoke — the grocery store garlic (California White) is an artichoke garlic, though other varieties have more complex flavors. Bulbs tend to have multiple layers of cloves.
Silverskin — often the last in the season to mature, these are the longest-storing garlics.

Elephant Garlic

This is a common “garlic” planted by many gardeners because it has large, easy to use bulbs with a garlicky flavor. Though it is technically not a garlic species – it is a type of perennial leek.

Root washed perennials – 3 months later

You’ll recall that in July I posted about root-washing perennials before planting them in the middle of our typically hot and dry summer in the Pacific Northwest. I wanted to update everyone on how they performed now that we’re heading into our cooler and wetter fall months.

Just to remind you, here’s a photo of the garden right after planting:

And here is the same garden, 3 months later:

No plants died; in fact, as you can tell, they all thrived. They were watered twice a day during the hottest months and now are rain watered only. (The underlying soil is an excessively drained glacial till, which is why we water frequently during esablishment and why we don’t worry about the drainspout. Water doesn’t stay around long.)

I used no fertilizer. I did add the soilless media from the root washing to the top of the soil and then covered with woodchip mulch.

There was, of course, a period of about 6 weeks post planting where there was no above-ground growth. But all of these plants retained their flowers, which kept our bees and other pollinators (butterflies and hummingbirds) happy. In August, the plants started to put on new growth at a furious rate now that roots have established.

Take some time and go back to the original post (which is linked in the first sentence. Look at the roots – before and after washing and pruning. Now look at the results.

Why wouldn’t you plant this way?

My cucurbits won’t stop having sex.

Not really a botanically-correct statement, but you know what I mean. John Porter’s previous blog post did a great job of explaining cucurbit reproduction (loved the Pucchini). Though I was surprised to learn “not getting any fruit” is actually a problem. Can’t say I’ve had an issue with that, ever. We have a really vibrant bee population and they’ve been super busy.

I love growing squash of all sorts, despite not being a terribly gifted vegetable garder. Past Garden Professors posts have addressed this issue. One might ask, why on earth would a two-person household need a 60-foot-long row of zucchini? Because we can! Though if I recall, I intended to go back and thin the row. Whoops.

The zucchini hedge. And those aren’t weeds, they’re *biodiversity*.

By late summer, we usually end up with gummy stem blight, powder mildew or squash stem borer No sign yet, though any of these goodies could show up next week. The plants are all healthy and ridiculously enormous. It’s been very warm and dry, but we have a nice drip irrigation system in place.

So guess what happened when we got too busy to check on them for three days? Many more were still on the plants when I snapped this pic. I’ve worked zucchini in some form into every meal except breakfast. Joel’s still being a good sport. Next step is anonymous *gift* bags to folks at the office. Though I think I’m getting a reputation.

Normal-sized zucchini at top of photo for reference. Aargh.

Not all zucchini taste alike, as true fans know. The pale hybrid Bossa Nova, right, has very creamy and tender flesh with seeds that are really only noticeable when it gets, er, hefty. Bossa Nova is a recent All-America Selection and perfect for use with those spiralizer thingies. The ribbed/striped variety is Costata Romensco – an heirloom variety with really wonderful flavor. Humongous plants though, probably not the best choice for square foot gardening fans. Tigress is the white-flecked green selection, allegedly more disease resistant than most. Bright and sunny Gold Rush, an old-school AAS selection, adds some color and is a bit sturdier/keeps longer than yellow summer squash.

I won’t be trying to save seeds – as John noted, can be very tricky/futile when there are other cucurbits about. Plus it’s too much fun to pick out next year’s selections from the winter seed catalogs, when the prospect of bountiful zucchini stacked like firewood actually sounds appealing.

Sex and the Single Squash: A study in plant sex, sexuality, reproduction, and seed saving

In the 1960s, author and future Cosmopolitan magazine Editor Helen Gurley Brown scandalized the country with her book about independent single women called “Sex and the Single Girl.” Taking a page from Ms. Brown, we can have a discussion about “Sex and the Single Squash.” Here, we can talk about plant floral structure and reproduction and its effect on fruit production and even seed saving. A true discussion of the “birds and the bees” if you will. This is especially important in the vegetable and fruit realm, since reproduction is why we get tomatoes, peppers, apples, plums and such in the first place. It also is important for producing seeds, as those arise from the reproductive process as well.

Whether you knew it or not, flowers are not just different in appearance from plant to plant, but the ways in which they are pollinated and turn into fruit are different as well.

Some plants have what are called “perfect” flowers where both male and female parts are present, such as roses, apples and dandelions. In a way of speaking, you could say that these flowers are hermaphroditic. These flowers may or may not be self-pollinated. Depending on species genetics, some plants can self-fertilize (like tomatoes and beans) and others require cross-pollination (like apples).

Other flowers are “incomplete,” meaning that they have separate male and female flowers. Some plants with “incomplete” flowers are called dioecious (Greek, meaning “two households”), and have distinct male and female plants such as ginkgo trees, holly bushes and kiwi vines. Some “incomplete” plants are monoecious and have distinct but separate male and female flowers on one plant — like squash, cucumbers and corn.

So, here’s where the vegetable garden comes in — one of the questions that I get every year without fail has something to do with why most of the flowers on a squash or cucumber or other cucurbit (that’s what we call plants in this family) plant do not produce fruit.

There are a few explanations – high heat causing aborted flowers or fruits or improper pollination, absence of pollinators, or, most likely, the fact that some of those flowers were never going to set fruit because they were male. In answer, I have to explain that about half or more of the flowers on the plant are male and are, unfortunately, anatomically incapable of producing fruit.

There are a few ways to tell male and female flowers apart when it comes to members of the cucurbit family.

First, look at the base of the flower. If the base is swollen and looks like it is a tiny version of the mature fruit, then it is a female flower.

If the base is just a straight stem (in flowers, this stem is called a peduncle), then it is a male flower.

The second method is to look inside the flower. If there is one large central structure, called the pistil, that indicates the flower is female.

Male flowers will have several, smaller stamens inside. Female flowers also tend to be larger than male flowers.

In the world of the single, available female squash blossom, life revolves around attracting honey and other native bees that have also recently visited male flowers to assure pollen transfer.

All members of the cucurbit family require this pollination tango to make sure that the female flowers produce fruit.

Each species and even variety of squash have a different ratio of male to female flowers. The ratio is usually about 1-to-1, but it is not unusual to see varieties with many more males than females.

Many of the plants also produce an abundance of male flowers early in the season, sort of as a teaser to make sure bees are attracted to the plant later on to pollinate the female plants.

So if a majority of flowers die early in the season without setting fruit, or about half of the flowers die throughout the season, there is nothing to worry about.

If female flowers are dying throughout the season without producing fruit, though, there is a definite problem. This means that there are no bees available to pollinate the plants.

If fruits have shrunken parts or misshapen, then there could be an issue of incomplete pollination from not having bees around. This could result from not having enough food for them in the area to encourage their presence, or from weather being too cool or wet for bees to get out and pollinate.

The lack of bees could also be the result of improper use of pesticides in the area.

If it seems like the birds and the bees aren’t happening in your garden, there are ways that you can ensure fruitfulness by taking matters into your own hands.

Transferring pollen from male flowers to female flowers can be accomplished using a small artist’s paintbrush or by simply pulling off a male flower and using it to apply pollen directly.

Gardeners who want to save seeds from plants in this family should also pollinate flowers by hand, and actually go so far as to protect the female flower from outside pollen using some sort of cover.

In fact, this method is often used by plant breeders or those who want to save seeds of crops that easily cross-pollinate. Hand pollination followed by bagging the flower to keep pollen or pollinators away to avoid accidental unwanted pollen is often used to produce.

Believe it or not, several members of the squash family that look or taste nothing alike are the same species and can cross-pollinate. For example: Zucchini, summer squash, pumpkins, scallop squash, decorative gourds and acorn squash are all in the species Cucurbita pepo and can cross with each other.

A few years ago, one of my Master Gardeners came up to me at the end of a meeting and asked me what was wrong with her zucchini. She handed me an object roughly the shape of a zucchini, only a bit larger and splotched with orange. She had saved the seeds from the year before.

I immediately answered that her zucchini had crossed with a pumpkin. Both of these plants are the same species and can easily cross pollinate. Even if you don’t have pumpkins in your garden, bees can travel 2 miles or more in search of food. So she was left with what I would call a Puccini.

Easy cross-pollination of varieties is why the most common heirloom crop varieties you’ll find are tomatoes and beans. Both of these crops have closed flowers that help resist cross-pollination.

They are most likely to be self-fertile, meaning that the flower will pollinate itself without outside assistance. This helps the plant breed true — so next year you end up with something that’s roughly the same as what you had this year. These plants can be just a few feet away from a different variety and they will not cross pollinate.

If you want to save something that is bee-pollinated, like your squash, pumpkins or cucumbers, you might want to do the brush and bag technique. Otherwise you might end up with a surprise in the garden next year.

The heirloom varieties that we often save are open pollinated, meaning that when they cross with themselves their genetics are relatively stable and you won’t see a lot of difference from year to year. (There will still be some difference, so if you save seeds for a long time you can end up with your own strain of a variety suited to your garden and location.)

Hybrids, on the other hand, have less stable genetics than the open pollinated varieties. With the way genetics work, some of those offspring will have traits of the mother plant, some will favor the father and some will be similar to the plant you are trying to save (and some might look like the milkman).

When seed companies sell hybrid varieties, they have to maintain a population of the mother plant and father plant to cross them every year to get the specific hybrid variety.

While the results of saving seeds from hybrids will be unpredictable, it can also be fun. My friend, plant breeder Joseph Tychonievich, points out in his talks and his book, “Plant Breeding for the Home Gardener,” that you can save the seeds from plants most closely resembling the desired plant over several years.

Just keep planting your selected seeds and harvesting the closest one to what you want. After about three or four years, you can end up with a relatively stable, perhaps even open-pollinated variety, that is your very own based on that hybrid variety you love.

And if you end up with a cross-pollination, either purposeful or accidental, you won’t see a difference in the fruit from this growing season (except maybe in corn, but that’s another story) Those changes won’t be apparent until you grow out the seeds you saved. So you won’t know until next year if you have one of those pucchinis.

And don’t forget: If you do have an overabundance of male squash flowers, they are edible too. You can put them in a casserole, fry them, stuff them, and more.