Potted plants…really potted

A week or so ago my new friend Doug wondered about some gardening advice on the radio: would adding vodka to paperwhite narcissus make the flowers less “floppy?” The explanation he’d heard was that alcohol would burn the roots and reduce stem growth. Then today I received an email newsletter with the same intriguing information. This newsletter referred to a 2006 article that appeared in HortTechnology as the source of this information.

The study by Miller and Finan has generated a lot of interest in the gardening community, especially this time of year as people get ready to force bulbs for indoor blooms. Unfortunately, that enthusiasm isn’t evident among researchers. Neither the original authors nor any other researchers have continued this work; the HortTechnology paper has never been cited in any subsequent publication.

This is unfortunate – because inquiring minds want to know WHY alcohol causes narcissus stems to be shorter. Miller and Finan hypothesize that it’s simply an osmotic effect and allude to preliminary data that support this, “but additional work will be needed for confirmation.”

So I’ve looked into other scientific articles about ethanol and roots for insights into this phenomenon. There’s nothing on narcissus, but others have studied trees, forsythia, tomato and barley reactions to root-zone ethanol. In all of these cases, exposure to ethanol resulted in reduced root growth, decreased water uptake, and reduced leaf transpiration.

How does this translate to shorter stems and leaves? A reduction in water uptake and movement through the plant – that is, from roots through the stems and out of the leaves – can reduce movement of growth regulators like cytokinins from roots to stems and leaves. It can also mean that the plant contains less water and is less turgid as a result. Both growth regulators and cell turgidity are important in cell division and elongation. Reduced cell expansion will cause stems and leaves to be shorter and/or smaller as a result. This same phenomenon can be seen in plants grown under saline or droughty conditions: these plants are always smaller than their normal counterparts.

So what your grandmother used to warn you about is true – alcohol WILL stunt your growth!

So what to plant under power lines?

I’m going to add a bit more to Bert’s discussion.  Through the efforts of Dr. Eric Wiseman of Urban Forestry at Virginia Tech, we have a
Utility Line Arboretum (ULA).  Modeled after Dr. Bonnie Appleton’s original ULA for Virginia at the Hampton Roads research station, Eric’s includes many woody taxa suitable for planting in the vicinity of power lines (see a nice list of Bonnie’s favorite power-line-friendly taxa here).

Eric came to me with his plan in 2006 and we found some space in our Hahn Horticulture Garden to get it going. Funding came through from both the Virginia Department of Forestry and the USDA. He’s now up to 50+ specimens, including a “no-no” tree for a demonstration of relative size. The Urban Forestry Club students maintain the site and Eric uses the ULA for both education and outreach.  Our hort garden visitors are free to wander through the well-labeled display. Interesting story:  obviously, this would be more effective with a faux power line for scale, like Bonnie has at Hampton Roads. Our campus architect said “heck no.” Apparently Virginia Tech has gone to great lengths and expense to get all power lines/utilities below ground.  And the ULA is adjacent to the much-visited baseball field.

That’s Eric on the right, demonstrating proper planting techniques.

Our Horticulture department has a great relationship with Forestry; especially the Urban Forestry section. Their students take our Landscape Establishment and Urban Horticulture courses and we encourage our landscape contracting students to take Arboriculture. Several are minoring in Urban Forestry (or vice-versa). Just thought I’d share a nice success story – one that should make Bert’s maligned arborists happy!

Utility arborists: Give ‘em a break

One of our semi-recurring themes on the Garden Professor’s is our WOW’s or “Why Oh Why’s”.  As in “Why oh why do nurseries continue to sell invasive plants?”  Today, I’d like to turn things around a bit and look at a group of people that are often maligned by the public but, in fact, are getting a bad rap and could use a break; utility arborists.


Right tree, right place?

Utility arborists face a nearly impossible and unenviable task.   The goal of every electrical utility is to provide safe, uninterrupted power to their customers.  What do their customers do in return?  Plant large, fast growing trees under powerlines.  This invariably necessitates line-clearance pruning and, in some cases, tree removal.  So who takes the wrath of the neighborhood?  The oblivious homeowner who planted a row of Norway spruces under the lines? Or the trained professional arborist that does the trimming?


Betcha can’t top this…

Among the arborists with whom I interact, utility arborists are often the best trained and the most professional.  They have to be.  An amateur pruning around electrical lines suspended 50’ in the air in a bucket lift is virtually guaranteed a Darwin Award nomination.  Arborists can’t even win when they try to do the right thing.  Many utility forestry programs utilize directional pruning as an alternative to topping or removing trees.  When done properly, directional pruning allow trees to coexist with powerlines and enables neighborhoods to continue to benefit from large trees.  A survey by Mike Kuhns at Utah State a few years ago, however, found that homeowners actually preferred the look of a topped tree to a tree that had been directionally pruned.  Granted, directional pruning isn’t always pretty but it’s vastly preferable to topping or removal.


The utility arborists I know are dedicated and ‘tree people’ in the best sense.  If they lived in a perfect world, the right tree would always be planted in the right place.  Since it’s not they have to rely on techniques like directional pruning to help ensure safe and uninterrupted power.  So give ‘em a break.

Pesticides and Wildlife

If you follow this blog then you know that I write a lot about pesticides.  They’re something that I enjoy reading about and studying.  For whatever reason, I find them fascinating.  That said, they can be some of the worst things for wildlife.  But there are pesticides that are more “wildlife compatible” than others, so today I’m going to cover some of the worst pesticides that you can use in terms of wildlife, and some of the pesticides that might be more acceptable (though far from perfect).

First, here’s a brief rundown of pesticides that have been some of the worst wildlife offenders over the years.  Fortunately most of these are gone.

1.  DDT – long gone (though I know people who still have old bottles locked up in chemical cabinets here and there).  Modern evidence points to it not being as bad for human health (cancer) as many made it out to be, but it was a mess in terms of environmental effects — it built up in the environment (it is stored in the body and is not rapidly excreted — in large part because it isn’t water soluble — so when a predatory bird ate a small mammal who had DDT on (or in) it, all of that DDT would stay in the bird — and the DDT from the next mammal it ate, and so on — this is called biomagnification) and resulted in predatory birds producing thin-shelled, barely viable eggs.  Another problem with DDT was that it lingered for a long time — it doesn’t break down quickly.  It had other problems too – but the biomagnification and persistence issues were the most obvious and, at least to me, the scariest.

2.  Endrin – Relatively closely related to DDT, but a lot more toxic to a lot more animals and so a lot scarier.  Once upon a time this stuff was used to all but sterilize fields.  Toxic to everything that moves, and, like DDT, it built up in the environment.  This stuff was (fortunately) never really used by homeowners.

3.  Temik (aldicarb) – Nasty, nasty, nasty.  EXTREMELY high acute toxicity, AND it’s water soluble.  A pesticide which I have had to use in the past.  Apply it to a tree (I was working with pecans when I used it) and that tree’s foliage would be free of any insects.  And, amazingly, the stuff didn’t translocate to fruits and veggies – if it weren’t so darn toxic to things besides insects it would have been a great insecticide – some people still consider it a great insecticide.  This stuff was known for its misuse.  Apply it near a weed which deer eat and that weed would absorb the pesticide and poof! No more deer.  Agonizing death too.  Wolves and coyotes could be poisoned with just a little bit of tainted deer meat.  This stuff wasn’t supposed to be used by homeowners, but, again, it is known as much for its misuse as its use.

Fortunately most of those over-the-top killers are gone or on their way out.  Still, in your garden you do have the opportunity to use some poisons which it would be best for you to avoid if you’re interested in saving/protecting wildlife.  These poisons are called “broad-spectrum” poisons and they are preferred by many because they kill so many different types of pests.  Unfortunately being able to kill many kinds of pests usually also means that they’re able to kill many types of good creatures.  Many pesticticides such as sevin (carbaryl), pyrethrin, orthene (acephate), and sulfur are broad spectrum poisons that you should avoid, but here are some that, if you want to conserve wildlife, you should be especially wary of.

1.  Permethrin – This is probably the most used broad spectrum insecticide used around gardens today.  It will kill just about any insect which it touches and it lasts for about 10 days.  It is certainly effective, but it shouldn’t be used by anyone who wants to encourage insects or the birds who eat insects in their gardens.

2. Metaldehyde – This is a very effective slug poison.  It is both attractive and deadly to dogs and cats, and is thought to affect birds and small mammals as well though there aren’t as many documented cases of wildlife poisoning as there are of domesticated pets being poisoned.

3.  Copper sulfate (Bordeaux mix) – This is an organic fungicide that is often overapplied because it is considered safe.  It can limit the plants which grow in an area, and it is extremely toxic to aquatics – keep it away from water.  Finally – copper doesn’t break down – as you use it over the years it will build up in your soil – so try to stay away from it.

And finally, here are some which, if they are used properly, are less likely to affect wildlife.

1. Kaolin clay – it’s not popular, but it’s out there if you look for it.  This is a type of clay which it sprayed onto plants to protect them from insects.  It tends to work pretty well (it’s not perfect), but it has minimal effect on wildlife.

2.  Insecticidal soap – It will kill some insects that you don’t want to kill, but it’s a heck of a lot better than permethrin.  It is unlikely to hurt mammals or birds.

3.  Roundup – The controversial part of me wrote this.  Roundup has been implicated as doing all kinds of things to aquatic organisms, but, if it is only sprayed on the leaves of the plant you want to kill, it is not going to cause any significant environmental damage (besides removing a plant that wildlife may want for food).

Want more bird visitors? Nonnative plants may be the answer

We’ve posted before about the native vs. nonnative conundrum, especially as it relates to invasive species.  So let’s complicate the issue a bit more by considering how birds are affected by our landscape choices.

About 10 years ago my UW colleague Sarah Reichard and I collaborated on a literature review on the interaction between birds and non-native plants.  While we know that invasive plants can displace native plants and create less biodiverse environments, the resulting impact on species like birds is not so cut and dried.  And what about noninvasive, nonnative plant species?  How do they affect bird populations?  Here are some of the practical bits of information that we found:

1)    Nonnative shrubs and trees are often chosen for their brightly colored fruits, especially those that produce them in a different season than native plants.  Winter color is highly valued by gardeners.

2)    Frugivorous birds (those that eat fruit) generally benefit from the introduction of fruiting species as an additional food source, even if the species is invasive.

3)    Birds tend to prefer fruits that are red and/or black, or that have red arils or pseudoarils.

4)    Birds tend to prefer fruits that offer the most pulp; interestingly, highly invasive plants species tend to have larger fruit displays and therefore higher bird usage than less invasive relatives.

5)    Additional food sources can allow frugivorous and omnivorous birds to expand their ranges and/or their breeding seasons.

6)    Nonnative shrubs and trees with structural features such as thorns and spikes can provide protection to small birds from predators.

It’s clear that birds are highly adaptive and will quickly learn to utilize new food resources – and in doing so, may contribute to their spread through seed dispersal.  It’s enough to make your head spin.

Here’s what I recommend for choosing bird-friendly trees, shrubs and vines:

1)     Use native species first if they are adaptable to your site conditions.  (Note:  many native species, especially those of forested environments, don’t like urban conditions.)

2)    Be sure to provide structural diversity in your landscapes – groundcovers, small dense shrubs, larger open shrubs and small trees, big trees, and vines – to provide shelter and nesting habitat.

3)    Before choosing nonnative species, check the web for information on invasiveness.  The USDA Plants Database (http://plants.usda.gov/) has information on invasive species.  If it’s invasive, please don’t plant it!

4)    Birds see best in the red end of the color spectrum, so select plants with fruits and flowers that will attract them. 


Water is the answer!

Wildlife week continues!  My humble experience with my own gardens past and present, as well as our campus garden, is that the presence of water virtually guarantees the presence of wildlife.  One of the National Wildlife Federation’s top requirements for becoming a  Certified Wildlife Habitat is “supply water” (another requirement: "$20 fee").   Water is, of course, the beverage of choice for most animals (though I did hear of a squirrel that preferred beer). And some creatures require it as a substrate in which to reproduce (that sounded a bit clinical).  Unfortunately, the popularity of water gardening, according to garden trend surveys and such, peaked in the late 1990’s and has decreased since.  I’d imagine this goes hand in hand with the desire for “no maintenance” landscapes. Whatever. I will not have a garden without moving water in it.  

Our first pond-building experience. Dig 11′ x 16 hole with concentric steps. Place excess soil behind pond to create stream/falls/unintended volcano. Line, add river stone and gravel. Add water and LOTS of plants to disguise said volcano


True story that has nothing to do with wildlife*: We put this house up for sale one spring when the garden was kickin’. Within 10 minutes of the Realtor putting the sign out front, a truck drove up. The couple walked straight to the pond (at this point outfitted with a spiffy patio) and said "We’ll take it."  I said "don’t you want to see the inside of the house?" and the young woman responded "Sure, I guess we need to."  Sold it at 99% of asking price. Never underestimate the value of landscaping!!!

Back on topic…The sound of moving water is an essential part of the experience for me. Makes pulling weeds in the vicinity almost pleasant. Fish, tadpoles, snails, and salamanders populate our wee pond.


Watching the birds bath on the shallow gravel beach is delightful. The pump runs all winter, keeping the water moving and mostly open.  I’m pretty sure that in the dead of winter, it’s the only unfrozen water source for quite a distance, judging from the multitude of critter tracks in the snow.

Water makes a garden more pleasant, adds value to our home, and increases the odds of survival for the wildlife during the toughest times of drought and cold.  Now get digging.

*Actually, there was a wildlife-related incident…when the buyer’s Realtor took them down the exterior steps to inspect the cellar, he reached inside the door and put his hand on a 5′ long black snake wrapped around the light switch. That was almost a deal-breaker.  Point being…if you create a wildlife-friendly yard, they will  come.  All of them.

The Garden Professors Go Wild!

It’s ‘Wildlife week’ on the Garden Professors.  One of the most common questions that we get when speaking to garden groups is, “What can I do around my home to promote wildlife?”   My stock answer used to be, “Throw a party!”, but only a handful of people ever got it so I’ve backed off of that one.  Anyway, since the subject of gardening and wildlife comes up so often we’ve decided to dedicate a week to the topic.

Questions about wildlife (the animal kind) always take me back to my undergraduate forestry days at Washington State University and Dr. Zamora’s Wildlife Management course.  Even though I’ve always been more of a plant person than and an animal person, I found this to be a fascinating course.  In fact, assembling the winter browse twig ID collection was one of my proudest undergraduate achievements.  Doesn’t seem like much; but try wandering the Palouse hills in the dead of winter and see if you can indentify 50 browse species without the benefit of leaves, you’d be proud too!  In addtion to a notebook full of mounted twigs and a mild case of frostbite, I took away from the course several key principles of wildlife management that have stayed with me over the years.

What do wildlife need? In general, all wildlife need four basic elements: food, cover, water, and space.  The specific types and amounts of these elements, of course, will depend on the type of wildlife you wish at attract.  Homeowners can provide or enhance these elements through plants or through other, non-living means.   Important non-living components include feeders, bird-baths or other water features, piles of rocks or sticks (provide cover for small animals), salt, and standing or fallen dead trees (provide habitat for cavity-nesting birds and mammals).  Plants can provide both food and cover.  Important plant components in designing for wildlife include evergreen conifers for cover, summer fruits and berries, fall fruits and seeds, winter fruits and seeds, flowers that provide nectar, and trees that provide nuts and acorns.

At this point the questions often turn to the importance natives versus exotics.  In light of Doug Tallamy’s book, Bringing Nature Home, many people assume that only native plants can serve these functions.  But there are several factors to consider here.  First, Tallamy’s discussion is largely focused on co-evolutionary relationships between native plants and native insects, and even here some of the reasoning is stretched thin (see Linda’s Feb. 12 post).  There is more to supporting wildlife on a broad scale than insect/herbivore interactions.  Non-invasive exotic conifers, for example, can certainly contribute winter cover, vertical structure, and edge effects.  And, while some animals have evolved very specific diets (think koalas and eucalyptus), many herbivores are generalists and in some cases even prefer to feed on exotics.  So, in thinking about wildlife it’s important to consider function and providing the elements animals need than to simply fixate on whether plants are native or exotic.  This is especially true on tough, disturbed sites where natives may be poorly adapted and unable to survive.  Habitat provided by an exotic will be preferable to no habitat at all.

Lastly, another factor to consider is whether attracting wildlife around your home is always a good idea.  Along with the wildlife we’d like to see, improving habitat may increase the likelihood of running into critters (skunks, raccoons, possums) that we’d rather not encounter on the way to take the trash out late at night. Also, in many parts of the country, people and their pets are encountering large predators such as cougars and bears with increasing frequency.  Obviously a lot of this is due to human encroachment into the predators’ habitat, but it may be prudent to consider a ‘defensible space’ strategy as we do for wildfires. Keep the elements that are likely to attract larger animals a safe distance from the house.  Stay tuned for more as ‘Wildlife week continues’.

NOTE: Thanks to my high school choir-mate and college soccer team-mate, Tim Schlender for the timely wildlife habitat cartoon.

Mysterious glowing object identified!

Ed, Wes and Paul all correctly identified Friday’s flower as a morning glory, probably an Ipomoea spp.  (They also made me feel rather soiled for pedaling flower porn.  Sheesh.)

What I find fascinating about these flowers is the unearthly glow at the center.  They’re pollinated by bumblebees among other species, and bees see best in the blue-violet-ultraviolet range.  If we were able to see this flower under UV light, you’d see those white areas become completely dark, creating a bullseye for bee approach.

Here’s why the white areas turn dark.  The pigments in a white flower are flavonoids, which absorb UV radiation and reflect visible light.  We don’t see into the UV range, so to us they look white (all that visible light bouncing back).  But bees and some other insects do see UV light, and these flavonoid pigments create patterns to help them find nectar and pollen.

Glowing mystery

Here’s a snippet of a photo I shot this summer:

What is this mysterious glowing object?  (I did not manipulate this photo in any way other than to crop it) Answer Monday!

By the way, Lynn asked if we could do a posting on how to make our landscapes more wildlife friendly.  We’re doing even better than a posting – we’re doing a whole week’s worth of blogs on the topic!  Thanks for the suggestion – and the rest of you feel free to suggest topics as well.

Big Trees for Crime Reduction

Like Linda, I believe that we don’t plant enough bare-root trees.  Trees that are harvested and sold bare root tend to establish better and recover faster from transplant shock than trees sold in containers or as B&B (balled and burlapped) stock.  But, in general, trees that are purchased in as bare-root stock are smaller than the other two styles, with B&B generally being the production method which yields the largest trees.

I disagree with Linda that, as a general rule, B&B stock should have its roots washed off prior to transplanting — I’ve done it and I’ve lost trees.  Most of the B&B trees that I know of where root washing has been successful have been small, relatively easily transplanted stock.  Once we have a few nice, big, long term studies that shows that B&B trees with their roots washed perform comparably to, or better than, normal B&B trees I’ll start to believe.  (I will note that, as a rule, it looks like B&B stock is dug and cared for much better here in Minnesota than Washington!)

I’m not going to go into the nuances of the arguments here — we’ve done it before if you want to check the archives.  But what I am going to point out is that a new study in Oregon has shown that bigger trees might help to deter crime.  Yet another reason for the people of this country to demand larger stock.

Despite what all of the research shows (that it’s better to plant smaller trees — preferably bare-root) people want big trees — they want an instant landscape.  They want it because to them it looks nice — and now its a way to protect your family too.

Historically this big stock comes B&B and is very expensive, cumbersome, and not the easiest things to successfully plant.  We need a new, cheaper way to grow large stock.  A number of researchers are working on different methods to produce large stock (special containers, bare root from a gravel bed) but nothing has worked out perfectly yet.  It’s going to be interesting to see how all of this shakes out in the future — especially with the loss of ash trees in the Midwest.