Interesting Plants – The Garden Professors™

Po-TAY-to, po-TAH-to: Let’s call the whole yam thing off!

As most folks in the US prepare for a Thanksgiving meal, or at least eat more Thanksgiving-inspired fall meals, potatoes and sweet potatoes often play a major supporting role in these most delicious victuals. Whether mashed, smashed, baked, candied, or turned into casseroles or pies, these starchy vegetables are stockpiled in grocery stores and markets in the fall for shoppers to turn into those tasty treats.

But sometimes there is confusion lurking in those grocery aisles and even in the minds of unwary shoppers….enter the “yam”. Wander down the canned vegetable aisle and you’ll see canned yams. Are they the same thing as sweet potatoes? And are they related to the standard potato that you usually mash, bake, or fry? I yam going to set the set the record straight.

First things first, sweet potatoes and yams are two totally different species so they are not the same thing. They’re even in different plant families so they aren’t even closely related. And neither of them are related to the regular old potato. So those “canned yams” at the grocery store are mis-named. They are sweet potatoes. Yams are rarely consumed or sold in the US, except usually though markets that sell specifically African/Caribbean foods.

Sweet potatoes are soft when cooked, thin/soft skinned, usually pretty sweet, and usually orange. Though there are some white-fleshed, less sweet varieties available. Native to tropical regions of the Americas sweet potatoes, or Ipomoea batatas, are members of the Convolvulaceae, or bindweed, family and are closely related to morning glories many of which are in the same genus Ipomoea. These sweet veggies are part of the root structure, so they are modified storage roots that store starches and sugars produced by the plant.

Yams, on the other hand, are white with a hard skin like tree bark, and are usually pretty dry when cooked. There are three main species of yams in the Dioscorea genus, which has its own family Discoreacea. Also tropical in nature, three different species were domesticated independently in Africa (D. rotundata), Asia (D. alata), and the Americas (D. trifida). Yams are monocots, meaning they are more closely related to lilies and onions than they are to sweet potatoes. Also, unlike sweet potatoes, the edible portion of a yam is a tuber, which is structure arising from modified stem tissue.

Piles of yams…that look nothing like sweet potatoes

And just to round out the tater trifecta – the humble potato. Sometimes called a white potato or an Irish potato (which are both bad descriptors for them because they come in many different colors, and while they are a staple in Ireland they originate from the Americas), these versatile spuds, Solaunum tuberosum, are members of the Solanaceae family and are closely related to tomatoes, Solanum lycopersicum. Their morphology has similarities to those of the yam, though, as they are tubers arising from the stem vs being a root like sweet potatoes.

So where does all the confusion come from?

There are various theories on how yams and sweet potatoes got caught up in this mash-up, and I don’t pretend to be an expert here. But the most common theory that I’ve seen is that enslaved African people held in the US south called the local sweet potatoes by the names they used for yams, as the sweet potatoes reminded them of the yam that was part of the staple diet in many African countries. The word yam is derived from nyam, nyami, or nyambi, meaning “to taste” or “to eat” in certain African language dialects. Adding to the story, apparently Louisiana sweet potato growers in the 1930s used “yams” as a marketing name for a new orange-fleshed sweet potato cultivar and the name stuck.

One thing I find interesting is that yam was used to describe orange sweet potatoes when the white fleshed ones (which are less common now) would probably more resemble an actual yam, both in appearance and flavor. In fact, in my travels in Rwanda I ate many white fleshed sweet potatoes, as they are now a major staple crop in many African countries. It is also interesting to note that the refugee farmers in our urban farm programs prefer to grow the starchier, less sweet varieties of sweet potatoes, which often complicates things as they can be hard (and expensive) to find.

Whether you cook sweet potatoes or “white” potatoes for your Thanksgiving feast, now you’ll know a little bit about how each of those crops are different…and you’ll at least know that sweet potatoes aren’t yams.

Poinsettias: from ditch weed to holiday super star (history, lore, and how to get those d@!% things to rebloom next year)

The holiday season creeps earlier and earlier each year, at least here in the US. Decorations, trinkets, and more start filling store shelves before summer is even over. But some holiday traditions can’t be rushed, like live holiday plants. Many of these picky plants have to be bought and cared for closer to the holidays, else they likely won’t look so festive once the holiday finally arrives. Since the origins of many of the holiday traditions are pagan and druid in nature, it stands to reason that plants are a major theme for the holidays. I’ve written before about the origins of using the plant parasite mistletoe as a holiday decoration and invitation for lip locking. And also about how what most people call a Christmas cactus is actually a Thanksgiving cactus and they are actually two different things (and there’s also a Spring/Easter cactus as well. We have amaryllis, paperwhites, cyclamen, Norfolk Island pines, pine-shaped rosemary plants, and more that make up our usual holiday decor. But none are so vibrant and indicative of the holiday as the poinsettia. So let’s talk a little about the history and lore of this plant and also about how day length affects its colorful holiday display. Just in case you want to try saving one from year to year.

Poinsettias take center stage as a 25 ft tall tree at Lauritzen Gardens in Omaha, NE each holiday season.

What is a poinsettia, anyway? It doesn’t really look like other plants.

This plant is a standout in the mostly weed-filled and much-maligned spurge family Euphorbiaceae. This family includes lots of different plants that take on a variety of forms. It does include many weeds, but also many houseplants that have much more of a cactus form than poinsettia. Relatives you might find as houseplants include a cactus-like plant with leaves on its margins (mainly just called Euphorbia), a plant called crown of thorns and a sticklike plant called pencil cactus. It is a weird family. Most of them do have a sap that can cause dermatitis in the skin or a stomach ache if ingested. But poinsettia has earned an incorrect reputation as being poisonous and a plant to steer clear of if you have kids or pets. Sure, ingestion might cause a tummy ache and associated symptoms, but the amount of poinsettia one would have to eat to actually have life-threatening symptoms is astronomical.

These ugly bits in the center are the actual flowers of the poinsettia.

While we enjoy poinsettias for their bright colors, it would be incorrect to say that poinsettias have large, colorful blooms. The colors that we see are called bracts — brightly colored leaves. These bracts change color much the same way leaves change color in the fall: They lose their green chlorophyll to expose the color beneath. This happens when the flowers, those ugly little yellowish lumps in the middle of the bract, mature.

While the classic red poinsettia (pronounced poin-SEH-tee-uh, not poin-SEH-tuh, by the way) lends itself to the classic colors of Christmas, it might be hard to figure out how this weed from Mexico found its way to the top of the list of traditional holiday plants. After all, it is a much more recent addition to the holiday decoration arsenal than the evergreens borrowed from ancient pagan rituals. And while we most often think of red poinsettias, there are hundreds and thousands of different cultivars and colors – and we’ve even taken to spraying them with dye and glitter (shudder).

Poinsettias these days come in all shapes and sizes and colors.

Poinsettias are famous for having a difficult blooming process. The plants are considered short day plants, thought the more accurate description would be a long night plant. This means that in order to set blooms, the plant needs a few weeks where it receives at least 12, and preferably 16, hours of uninterrupted darkness each night. This creates physiological and chemical cues that allow for development of floral structures, which in turn result in development of the colorful bracts. Even a few seconds of light in the middle of the night can stop, interrupt, or delay the process. This often makes saving poinsettias from year to year difficult, and can even make it difficult for commercial growers to provide darkness in our ever (artificially) brighter night sky.

How did a weed get associated with Christmas?

The poinsettia (Euphorbia pulcherrima) is a native plant (and can grow as a fairly large shrub or tree) in Mexico. The original name used for the plant, prior to Americanization, was cuetlaxochitl. I’ve seen them in several places around the world, including one as big as a tree in Kigali, Rwanda (other Euphorbia, like the pencil cactus also grow there). A local Mexican legend from the 14th century explains that a young girl on her way to Christmas Eve mass was upset that she had no gift for the baby Jesus and picked a handful of weeds on her way to church. As she placed the humble bundle of weeds on the altar, they erupted into brilliant red, and all those around exclaimed that it was a Christmas miracle.

Aside from the miracle legend associated with the flower, there are other connections between the plant and the holidays. The traditional red of the poinsettia is cited by many as a representation of a blood sacrifice and the shape of the flower as the Star of Bethlehem. Before poinsettias became a worldwide symbol of the holidays, Franciscan friars included the vivid plants in Christmas celebrations in the 17th century. In Mexico, the plant is also known as Flor de Nochebuena, or Holy Night (Christmas Eve) Flower.

From ditchweed to international holiday superstar

The poinsettia really didn’t come into its current fame until it was introduced to the United States in 1825, at the hands of a politician. It just so happened that the first U.S. minister to Mexico (this was before we had ambassadors) was an amateur botanist. He brought the plant back to his private hothouses in South Carolina, and then shared it with friends (including renowned botanist John Bartram) who introduced the plant to the nursery trade. It filled an empty spot in the nursery calendar, so nurseries were quick to embrace the plant.

This is the guy who brought you the poinsettia, and so much more.

The plant quickly was renamed Poinsettia (it was originally sold under its botanical name) in honor of the man who brought it to the country — Joel Roberts Poinsett. His contribution to the plant’s history and the nursery business in the U.S. was honored by Congress, which has declared Dec. 12 National Poinsettia Day. A date which, oddly, commemorates the date of Minister Poinsett’s death.

Aside from his botanical triumph and service as minister to Mexico, Poinsett was also an “agent” to Chile and Argentina, a state representative, a member of the U.S. House of Representatives and secretary of war. Most people would be surprised to learn that the man who brought you the poinsettia also oversaw the removal of Cherokees from North Carolina to Indian Territory in 1838 and the military during the second Seminole War. But he was also involved in the Columbian Institute for the Promotion of Arts and Sciences and a co-founder of the National Institute for the Promotion of the Sciences and Useful Arts.

This national institute, composed of politicians, promoted the use of the Smithson bequest to form a national museum. While they were defeated in their efforts, the institute went on to become part of the result of the Smithson bequest — the Smithsonian Institution.

The poinsettia didn’t become common holiday fair for the general masses until Paul Ecke Sr., a German immigrant living in California started growing them on a large scale. Ecke and family were also responsible for breeding poinsettias, turning them in to a weedy plant in to the more robust, bushy form we see today. While the Ecke family has moved a lot of production overseas, they are still responsible for 70% of the poinsettias sold in the US and nearly half of all poinsettias sold worldwide.

Paul Ecke Sr, the Poinsettia King
(1895-1991)

So, how can I save my poinsettia and get it to rebloom next year?

In theory, this is pretty simple, but as GP alum Holly Scoggins points out it can be difficult to keep these plants happy and healthy, let alone get them to rebloom so that the bracts will color up.

But if you do want to save your poinsettia from year to year, here’s how to do it:

Keep your poinsettia in a bright but cool spot to keep it colorful longer. When the leaves start to yellow, or you are done with it for the season, slowly reduce watering until it loses all leaves (and colorful bracts, which will be last to go) and goes dormant.
Store the plant in a cool (50-60 F), dry, and dark area. Keep the soil on the dry side, but water just enough to keep the stems from drying out.
After the danger of frost has passed, or in April or May (if you don’t have frost), remove the plant from storage and repot. Use a good quality and light soil mix – poinsettias do not do well with heavy soils. And it turns out that since poinsettias are typically sold as disposable plants, the soil they come in is crap (even high end houseplants these days come in cheap, crappy soil). Practice root washing to remove all the old soil and pot up to a larger size if the plant seems root bound.
Place the plant outside if possible after the danger of frost has passed, or grow in a bright, sunny window. Keep humid, well watered, and fertilized throughout the growing season.
As the danger of frost approaches, move the plant indoors in a bright, sunny window (if it isn’t kept indoors). Ideal temperatures are 75F during the day and 60-65F during the night.
In late September or early October, move the plant to an area that receives no light at night, even from outdoor street lights. The easiest way to provide exact light and dark needs would be in a dark room with lights on a timer. Provide no fewer than 12, and preferably 14-16 hours of uninterrupted darkness and 8-12 hours of light per day. Alternately, you can move the plant to a dark room or closet for its dark period.
After flowers begin to form and bracts start to change color, move to a preferred place in the home for the holidays. Continue to keep the plant well watered, and regularly fertilized through the holiday season.
Rinse and repeat, if desired.

Sources:

NMSU Extension – Poinsettias: Year after Year

Ambius – The long, strange tale of the poinsettia

UMN Extension – Growing and caring for poinsettias

Investors.com: Paul Ecke Sr: ‘Poinsettia King’ Cultivated a Holiday Tradition

Houseplant Hubub: The rage about variegation

It is no secret that houseplants are hot right now. Interest was growing before the pandemic, especially with millennials and younger folks. Then the pandemic hit. Houseplant interest skyrocketed since people were stuck at home and wanted to bring a little bit of nature indoors to make their spaces a little more cozy for 24/7 habitation.

This has caused the demand, and price, of many houseplants to increase, especially if they are on the rarer side. One thing that increases the price of many plants is when a variegated version of a standard plant has been developed.

Just as an example, after posting a photo of my “reading nook/houseplant oasis” in my home office I was informed that variegated form of a Monstera deliciosa vine that I had was the highly sought M. deliciosa “Albo-Variegata” cultivar, usually referred to as a Monstera albo, or just Albo. Folks were reaching out to buy cuttings right and left. I ended up selling 5 single leaf/node cuttings over one weekend and made $675 in the process. That’s right, $675! The most variegated of the leaves sold for $200, and that was actually a bargain price. The garden writer for the local paper, the Omaha World Herald, even picked up the story and shared it as a focus on the four new houseplant shops that have popped up in the city over the last few months.

Had my plant not had the variegation that made it an albo, each of those cutting would have been worth a few dollars apiece. So what makes some plants variegated and others not? Sometimes the variegation is the standard form found “in nature” and sometimes it is a cultivar or variety that has been bred or discovered by chance. Let’s take a look at all the ways that a plant can get that variegation, whether it is standard or rare.

Chimeric variegation

My *Monstera albo* that caused the hubub

This is a common form of variegation and the one responsible for the variegation of my Monstera. In this form, a genetic mutation in some cells changes that cell’s ability to produce chlorophyll. It may reduce chlorophyll production, resulting in yellowish or silver coloration, or eliminate chlorophyll altogether, resulting in white coloration.

The name chimeric or chimeral is based on the fact that the plant displays two (or more) chromosomal patterns on one plant. In Greek mythology, a Chimera is a frightening fire-breathing female monster with the head of a lion, body of a goat, and the tail of a serpent.

Image result for chimera — An ancient chimera statue

This variegation can be stable, where the pattern persists throughout the plant. Or it may be unstable, where it is random on certain leaves and parts of the plant can revert back to the standard green form. These plants can also produce leaves that are almost totally white, which usually results in a leaf that will die since it can’t photosynthesize.

This type of variegation also means that cutting or propagations may or may not be “true” to the pattern. It can be random. For my Monstera, the presence of white striping in or around the node that will become the new plant is the important marker for whether the new plant will be variegated or not.

One common chimeric houseplant is the plant formerly known as Sanseveria, now a Dracena (Snake plant or mother-in-law’s tongue). Many of the different color patterns on some of the cultivars are due to cuttings taken from different parts of the “original” natural type that display different colors on them.

Viral Variegation

While beautiful, this variegation will often reduce the productivity of plants if not kill them outright. There aren’t a lot of houseplants that have this variegation, but some Hosta cultivars do. Probably the most famous case of viral variegation is the Tulip Mania during the Dutch Golden Age (in the 1600s). Prices of tulips skyrocketed and people were buying them as investments (maybe like the current houseplant craze, or GameStop stocks, or bitcoins). Unfortunately, as the virus reproduced plants kept getting weaker and weaker. Eventually the tulip market collapsed and lots of people went broke. Let’s hope that doesn’t happen with the houseplant market….at least with my fancy Monstera.

Natural Variegation

This type of variation occurs when the patterns or colors of the variegation are written into the DNA of the whole plant. It will occur regularly throughout the entire plant, not randomly on some parts as in chimeric or viral variegation. This variegation is passed through cuttings and usually through sexual reproduction from seeds as well, though different variations may pop up that cause a more desirable or rare cultivar.

Common houseplants such as Tradescantia, Maranta (prayer plant), and many more common plants have this type of variegation.

Blister, bubble, or Reflective Variegation

Reflective variegation on *Phildodendron* ‘Birkin’ following veins in the leaf

This type of variegation occurs when there is an air pocket or bubble between the lower layer of tissue and epidermis, or skin, of the leaf. The lower level typically has green pigmentation from chlorophyll and the epidermis does not, resulting in a pattern that is usually white, silver, or yellowish though other colors could appear. This pattern can be blotchy or splotchy like in some types of Pothos and Pepperomia. It can also occur along the veins of some plants, resulting in white or silver veins on green leaves, as in some Alocacia, Anthurium, and Philodendron varieties.

In conclusion…..

Even if you don’t have an expensive plant hiding in the corner, houseplants can add lots of fun and color to your living spaces. And sometimes, your houseplant obsession can even pay for itself. Online swap and sale groups have houseplant afficionados swapping and selling cuttings and plants all over the place. So enjoy your plants….and maybe you’ll find a cash cow hiding in the corner. Don’t mind me….I’m just over here propagating more Albos to fill up my “mad money” jar.

Sources

Variegation mutants and mechanisms of chloroplast biogenesis

Variegated Indoor Plants: The Science Behind The Latest Houseplant Trend

Chimeras and Variegation: Patterns of Deceit

Testing, testing, 1-2-3: Trialing new plants for the home garden

How do you know that plants will do well in your garden? Do you research the types of plants for your region, study different cultivars, and select only things that have been proven to do well for your conditions? Or do you buy what catches your eye at the garden center, plant it, and then see what happens? I used to joke that my home garden was a horticulture experiment station, since I’d try all kinds of random plants or techniques and see what works for me. Now, I get to do that as a fun part of my job through the All-America Selections (AAS) program. You’ve likely seen the AAS symbol on plants or seed packets at the garden center or in catalogs. Heck, you may even have them in your garden (and not know it). I compare it to the “Good Housekeeping Seal of Approval” that you used to see on appliances, cleaners, etc. The AAS program is a non-profit started in the 1930’s with the goal of evaluating new plants so that home gardeners can purchase high quality seeds and plants and to assist the horticulture industry in marketing innovations from their breeding programs. You can read more about AAS and its history here.

A few weeks ago I traveled to Chicago for the All-America Selections (AAS) Annual Summit to receive their Judge Ambassador Award. I had signed up a few years ago to be a trial site for edible crops for AAS. The following year I talked my colleague Scott into signing up as a judge for their ornamental trials. The fun thing about the program is that we get to grow all kinds of vegetables, fruits, and flowers that aren’t even on the market yet. We get to see how well they grow compared to similar plants and rate them on a number of factors including growth habit, disease resistance, and performance plus flavor (for edible crops) or flower color/form (for ornamentals). It can be hard work, but it is rewarding to help identify true plant innovations and to see your favorites be announced as winners.

How the testing works
While the AAS Trials may not have the rigor of academic crop research, I do appreciate the procedures in place that provide objective and high standard results.

Breeders, developers, and horticultural companies submit their new plants that are planned for future introduction to the board of AAS for consideration in the trialing program. During the application process, novel traits of the plants are identified to ensure that the plant offers something new and exciting – these are the traits that judges will observe and score. The board reviews the application to determine if it fits within the program rules.

One great thing about the program is that trial judges are professional horticulturalists from universities, seed companies, botanical gardens, etc. – they’re people who know how to grow things and know what quality plants look and act like. There are trial sites all around the country, providing for replication and generalizeable results for most regions of the country. The conditions plants are grown in also vary by location. My trial is at a farm where management is minimal. When we were at the summit we visited the trial gardens at Ball Horticulture which looked much more maintained and pampered compared to mine. This gives data on a variety of maintenance levels as you’ll find in home gardens – some gardeners are very conscientious about maintaining their plants and others have a more laissez faire approach. In order to win as a full national AAS winner, the plants have to perform well across the country in all these different situations. Sometimes those that perform well in a few regions but not the others will be designated as regional winners.

Second, the tests are blind. This means that we do not know what the exact plant is, who the breeder or seed company is, or any other info other than what type of plant it is. To the judge, each entry is just a number. It could be from a seed company you love (or hate), your best friend, the breeder who was your advisor from grad school, etc. This makes the results fair and reduces the chance for bias toward or against a plant based on its origins. The ratings are just based on the plant.

Another part of the trial is comparison. It is one thing to grow a tomato plant and say “yep, that’s a good tomato.” Its another to grow a tomato and compare it to similar cultivars to say “yep, that’s a good tomato….but it is better than what’s already available on the market.” The goal of the program is to show how new plants have merit over older plants. We only need so many new tomatoes (and let’s face it, there are lots of new tomatoes – we test WAY too many in the AAS process for my liking). The board of AAS judges reads the entry info from the new cultivar being tested and selects plants (usually two) to compare it against. If the trial is a yellow cherry tomato, it will be grown and tested alongside other yellow cherry tomatoes. The scoring is based on whether its performance or taste is as good as or better than the comparisons. If most judges don’t rank it as “better” then it has no chance of winning.

Confidentiality and Proprietary Plants

The fact that the testing is blind, paired with the fact that results of “failed” tests are not released, lends itself to confidentiality. Another important factor about the testing is the proprietary nature of the tests and test sites. These are new plants that haven’t been introduced to the market (except for the case of perennial trials) and are usually for proprietary or patented plants. Test sites should have some sort of control over who enters them and signs prohibiting the collection of seeds, pollen, or cuttings are placed at the site. Believe it or not, the world of plant introductions can be dog-eat-dog and cutthroat.

So what if it doesn’t win?

One of the cool things about the test is seeing the announcements of the winners early the following year. You see the list of plants and think back to what you grew the previous season. If often find myself thinking “oh yeah, I remember that plant, it did really well” and sometimes even “how did that win, it did horrible for me.” This is a good reminder that we can’t base generalized garden recommendations on anecdotal evidence. What did well for me may not work for someone else and vice versa. All the results from the test sites go together to provide a general view of the plant performance. It will do well for some and not others.

So if most of the judges rank the crop as not performing, looking, or tasting as good as the comparisons the plant doesn’t win. And that’s it. Due to the confidential nature of the testing you won’t know that it failed the test. Even I won’t know that it failed the test. It will likely go on to market without the AAS seal where it will face an even tougher test – the test of consumer demand. Of course, many people may grow it and be successful, and some may grow it without success.

What are the AAS Winners and how do I find them?

There’s a list of plants announced each year through the AAS website and social media channels. You can find a list, in reverse order of winning (meaning most recent first) on the AAS Website. The site also has a searchable database if you’re looking for a specific plant. Since these plants are owned by lots of different seed companies and breeders, there’s also a retailer listing on the site. The AAS program also supports a number of Display Gardens across the country, including botanical gardens, university gardens, and others where the public can see the most recent winners growing. Here in Omaha we maintain a display garden for the ornamental plants at our county fairgrounds. We also have our on-campus garden which is used for our TV show Backyard Farmer (the longest running educational TV program in the country, BTW) which serves as a display garden for both ornamental and edible crops.

I recently shared the AAS Testing Program with the local news here in Omaha. Check it out:

Some of my favorite recent AAS Winners
Asian Delight Pak Choi – this was planted in May and didn’t bolt. We were still harvesting it in October.

Pepper Just Sweet – these plants were big and healthy even when everything else was struggling. The peppers were delicious.

Potato Clancy – potatoes….from seed! Just fun!

Pepper Habanero Roulette – All of the fruity sweet, none of the heat. A fun heatless habanero.

Dianthus Intraspecific Supra Pink– A reblooming, prolific Dianthus with interesting ruffled flowers.

Eggplant Patio Baby – container sized eggplant with mini fruits perfect for cooking or roasting whole.

Ornamental Pepper Black Pearl – Cute purple flowers lead to these shiny pepper pearls. Love the black leaves, too.

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/

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.

Notes from the botanical etymology division, toxicology subcommittee

By Charlie Rohwer (Visiting Professor)

The recent assassination attempt England, interesting and significant geopolitically, has reminded me about one of my favorite Latin plant names. A report on the radio stated that atropine therapy is used to treat the specific poison involved in the attempt. To paraphrase Dr. Randy Pausch, “I’m a doctor, but not the kind who helps people.” Therefore, I have no authority on the medical uses of atropine. The world Health Organization lists it as a preoperative anesthetic on its list of essential medicines, so it must be pretty important.

Atropa belladonna, Leipzig botanical garden

But I do like horticulture and I like words. That’s where my interests lie in relation to this story. Many medicines are or have been plant-based. Atropine itself comes from certain plants in the nightshade family. Like any chemical people use, dosage of atropine determines its effects; atropine can be medically useful, or it can be deadly. The drug is named after a specific plant from which atropine can be obtained, Atropa belladonna. The omnibotanist Linnaeus named it in 1753 (can someone come up with a better word for him than ‘omnibotanist?’).

‘Belladonna,’ as it’s commonly called, is a small shrub native to Europe and Asia. ‘Belladonna’ comes from the Italian words ‘bella’ and ‘donna,’ meaning ‘beautiful woman.’ An extract from the plant was applied topically to eyes during the Renaissance to dilate pupils. One sign of sexual arousal is dilated pupils, so the extract would cause a response that looked like sexual arousal. If you were a lady going to a fancy party during the Renaissance and you wanted to look beautiful, belladonna may have helped (according to beauty standards of the time). My optometrist told me atropine isn’t used for retinal exams today because its effects last too long.

The other common name for Atropa belladonna is ‘deadly nightshade.’ The drug, atropine, is made of two isomers of hyoscyamine, made by the plant (and some other related plants). At some doses, hyoscyamine causes muscles to relax (like the iris, for example) due to its effects on nerves that control muscles. At larger doses, it can kill because you need muscles to breathe and to pump blood at a reasonable rate. Dosage and route of entry are important!

The author with one of his favorite books.

So Atropa belladonna was used to make ladies beautiful, hence the epithet ‘belladonna.’ But what about ‘Atropa?’ What’s that mean? Where does the drug atropine ultimately get its name? My favorite book as a kid was “D’Aulaires’ Book of Greek Myths.” Linneaus borrowed from the Greek myth of the three Fates in order to name deadly nightshade. According to D’Aulaires, these goddesses of destiny “…knew the past and the future, and even Zeus had no power to sway their decisions.” Nobody can escape fate. The three fates were named Clotho, Lachesis, and Atropos. The fates are responsible for the thread of everybody’s life. Clotho spins the thread at birth, Lachesis measures it out and determines destiny (what’s on the thread and how long it is), and Atropos (‘inflexible’ or ‘unturnable’) cuts the thread after Lachesis has apportioned it. Atropos is the goddess directly responsible for the end of everyone’s thread of life, and her action is final.

Atropa belladonna simultaneously means something like ‘inevitable, inflexible death’ AND ‘beautiful lady.’ Indeed, the dose makes the poison.

Howdy and Previous Post Revisited 1.0

Greetings all, and good to be back in the saddle for the Garden Professors. It’s been a while since I’ve filled you in on my own personal gardening struggles (lots) and triumphs (few) as well as topics I think you’d be interested in. I’ve always appreciated the kind comments and good questions our readers pose, in response to my off-kilter posts and horrific punctuation.

I’m sure there is one BURNING question that long-time readers have:

“So how’s your Puya doing?”

“Fine, thank you!”

Well, mostly.

Long story short, I bought/committed to a Puya berteroniana in 2012. If you have no idea what I’m talking about: http://gardenprofessors.com/puya-report/

I’m sure many readers have been at the receiving end of a cactus spine or Agave poke; the genus Puya makes Agaves look like stuffed animals. Fish hooks line the margins of each leaf, and cascade over the side of the pot. Therein lies the problem…

Still alive, and doing pretty well, but Pootie the Puya really needs re-potting to realize her full potential (the blooms are outrageous, and the point of all this, as I mention here: http://gardenprofessors.com/the-eternal-gardening-optimist/)

I’ve attempted to “go in” a couple of times, but even leather grilling gloves get snagged. Need really strong tongs (two sets?). I’m probably going to have to just bust the pot. She didn’t make it out to the deck this summer due to the awkward pot situation. Suggestions welcome, especially from anyone who has wrestled with one of these (and lived)!

Rhymes with nārang

By Visiting Professors Dr. Charlie Rohwer and Ulrike Carlson

I’ve had this dream of doing a full academic etymological study of oranges, with the help of a second-cousin-by-marriage linguist and her historian husband. Being honest with myself, I know that’ll never happen. And also, honestly, they’d have to do all the work anyway.

But, the Garden Professor’s Facebook post about the citrus family tree revived my interest. Not for a full-blown academic analysis of the word ‘orange,’ but for a blog-friendly, factual, interesting post. So I got my linguist cousin Ulrike Carlson to edit for accuracy too.

The name given to the orange by Linnaeus was Citrus aurantium, and the only other citrus species he noted in his first volume of Species Plantarum was Citrus medica. The current taxonomy of citron is Citrus medica L., and bitter orange (or Seville orange, used for marmalade and Belgian beer) is Citrus aurantium L. According to Linnaeus, sweet orange and pomelo were separate varieties of C. aurantium (var. sinensis and var. grandis, respectively). For a pretty image of the family tree, see the National Geographic article here. Basically, it is now known that all common citrus fruits are hybrids derived from citron, mandarin, pomelo, and papeda.

The current taxonomy for sweet orange, Citrus sinensis (L.) Osbeck, clearly defines the fruit’s Eastern origin (sinensis comes from Latin for ‘Chinese’) and altered nomenclature (Osbeck refined Linnaeus’ original taxonomy). But the name given to bitter orange, C. aurantium, points to its South Asian origin, and here’s why. The Tamil (south India) word for orange transliterates to ārañcu; Sanskrit words look similar; the Persian nārang is derived from there. As the bitter and sweet orange hybrids were likely made somewhere between Northern India and Southern China, it would be expected that the European names for these fruits come from these or nearby areas too. The origin of Linnaeus’ aurantium are obvious. Aurantium is Latin for the orange tree, and aurancia is the fruit. If you say these words aloud, they all sound similar to each other, to nārang, and to the English orange.

But here’s where it gets more interesting, with a preface: the word apple has historically been used to describe any fruit that’s not a small berry. Also, bitter oranges were common in Europe before sweet oranges. In fact, when sweet oranges came on the scene in the 17th century, wealthy people built greenhouses or gardens (“orangeries”) specifically for the new, more delicious versions of the fruit.

Orangery at the Château_de_Versailles
By Djampa – Own work

My first time in the Netherlands, I noticed orange juice is called sinaasapelsap. I don’t know Dutch really, but…doesn’t that mean ‘Chinese apple juice?’ Sinaas: Chinese (sinensis); apel: apple; sap: …sap (juice)? I knew in French that it’s jus d’orange (juice of the orange), and I knew ‘orange’ in Spanish is naranja (looks & sounds a lot like orange and narang). Why would the Dutch call it Chinese apple juice? Fast forward a couple years, I’m in Denmark, and what do I see? Appelsinsaft. CHINESE APPLE JUICE…English, Dutch, Danish, they’re all Germanic languages. Shouldn’t the Germanic languages call it orange juice, like I do? Then it hits me. English is the odd duck here. The Germanic languages call orange juice ‘Chinese apple juice’. This reflects the name Linnaeus gave the sweet orange (var. sinensis, or ‘Chinese’). Best I can tell, among Germanic languages, only English, Afrikaans, and Scots gets their word for the sweet orange from the older word for the bitter orange, nārang.

*Citrus aurantium*
By A. Barra – Own work

That’s not the last word on the subject though. You can go to Italy for sweet oranges and get arance, the Czech Republic and get pomeranče (apple-orange), Ireland and get oráistí, Bulgaria and get oranzhev, or Portugal and get laranjas (aka, oranges). All words that come from nārang or aurancia. You can go to Estonia, Finland, Sweden, Norway, and Germany and get some kind of Chinese apples (aka, oranges). But even as most Italians eat arance, you’d instead ask for a partuallu in Sicily. Or you’d eat a portokáli in Greece, portokall in Albania, etc. The Portuguese, with their awesome shipping routes, imported sweet oranges from China, then grew and distributed them through Europe in the 17th century. They were a big improvement over the bitter orange (which would you rather have, marmalade from a bitter orange, or a juicy sweet orange?). So some countries called the sweet orange by the name of the proximal country they were shipped from, Portugal. Bitter oranges (AKA Seville oranges, named from where they were grown) are called pomerans (from apple-orange) in Swedish, Pomeranzen or Bitterorangen in German, pomeransen in Dutch…so it seems that when sweet oranges came to Germanic-speaking countries, the languages kept the word they’d been using for the bitter orange (calling it an orange-apple or bitter orange), and added a different word for the sweet orange, calling it a Chinese apple. This is all complicated because political boundaries have changed a lot in Europe, and languages borrow from each other. So northern Germans might still eat Chinese apples, but southern Germans might eat oranges.

Also, if you’re interested and you’ve made it this far, the color orange is so named because that’s the color of the fruit. It’s not the other way around. It’s a pretty recent color descriptor. That’s why robins, with their orange breasts, are called robin red-breast. There was no word for the color orange when the robin was first described.

Also of great interest is the House of Orange. If you’ve seen a Dutch soccer game, or been to the Netherlands, you’ll know they like the color orange. William I of Orange, basically the founder of the Netherlands, came from a principality called ‘Orange’, now in France, and the Dutch celebrate their royal family with the color of its namesake. BUT, Orange, France was named, a couple thousand years ago (before the fruit came to Europe), after a Celtic water god, Arausio. At the time, this had nothing to do with the fruit or the color. HOWEVER, since the middle ages, the crest of the French city shows orange fruit on a branch, and the crest for the German city of Oranienbaum (orange tree) has, you guessed it, an orange tree. According to Wikipedia, Oranienbaum was named after the Dutch House of Orange.

For more about how these languages are related, here’s a ‘simple’ chart.

Allium Fever

Ornamental onions are hot patooties. From big, bold, purple globes to small pink half-moons, there is no end to ornamental onion-y goodness out there with 30+ species and cultivars in the trade. There’s no substitute for ornamental onions in regards to architectural drama – the perfect geometric foil to wispy grasses, floral spikes, and umpteen daisy-thingies. The seed heads from the sturdier species will persist and add interest to autumn and winter perennialscapes (not sure if that’s a word).

Art-of-Gardening-COVER-3D-1 — Not one but TWO cultivars of Allium on the cover of the fabulous new Chanticleer book…

All are members of the Allium genus, just like those onions sprouting in your kitchen counter veg basket – hence the deer- and small mammal- resistance factor. However…there are some issues.

Can be short-lived. I have first-hand experience with this – plant, enjoy for a year or two, then…where did they go?
Bloom time is rather vaguely defined. Most catalogs list “early summer” or “late spring” for most cultivars. But if you want continuous purple orbs, what’s the order of bloom?
Can be expensive. Bulbs for some of the mammoth “softball” sizes will set you back $5-$7 each (the bulbs themselves are huge). This is of particular concern due to the first item.
Foliage failure. For some of the largest species and cultivars, the foliage starts to die back around (or even before) bloom time. Not a lot of time to put the necessary energy back into that big honkin’ bulb.

We already have a multi-year lily perennialization trial going in conjunction with Cornell and some other institutions. I thought I might try the same thing with Allium.

Student worker Lauren, after a long day of taking data on a gazillion lilies.

Unfortunately, I had this bright idea in November – well into the bulb-ordering season. I tried to compile as complete an inventory as I could, ordering from several vendors. Ended up with 28 species and cultivars – as much as the space prepared (check out that nice soil!) could hold, at our urban horticulture center near campus (Virginia Tech is in Blacksburg, USDA Zone 6, about 2000′). We put five or seven bulbs (depending on size) in each plot, and replicated the whole thing three times.

We’ll take data over the next three years on time of emergence, bloom time and duration, foliage duration (have a nifty chlorophyll meter that can help quantify that), some growth measurements, and perennial tendencies (or not). My hope is to end up with a really specific chronology of bloom times plus life expectancy. Yes, this was just a patented Holly wild hair; luckily I had some general funds to cover it. But I do think our little onion project will be of interest to more than a few folks, whether professional landscape designers or home gardeners. I know I’m excited to see the results ($30 for five bulbs – yeek)!