Sandra's Garden: proof not all Phlox are created equal

Species name: Phlox subulata

Common name: moss pink, moss phlox

Location: Sandra's garden

Last year I posted a blog about moss phlox, a native species we have in our garden that gets a little out of control in really sunny areas. It's a species native to North America, and one that occurs relatively commonly throughout its native range in bright and sunny, damp areas (despite also being drought-tolerant). It is much more common in the United States than in Canada. I knew this species was a popular garden plant based on what I've read about it, but I had never seen any of the cultivars created in greenhouses aside from the "normal" light purple type. Well, here's a spectacular demonstration of the "hidden" morphological variation that some plants contain. This variety of moss phlox was not created in the lab, but is a product of controlled breeding. Despite this, you would never find this variety of phlox in the wild unless it escaped from someone's garden.

So how do we "create" morphological variation in plants that is not typically seen in the wild? The secret is some patience, and a lot of time on your hands (it helps to have a greenhouse because it speeds things up a bit). Natural mutations in the wild create different alleles, or copies of a gene, that can show different morphologies if they have a chance to be expressed. Most of these mutations are what we call "recessive", which means you have to have two copies of the gene in order to be able to see the effect. This is good for the plant if the mutation is detrimental, but bad for gardeners if the mutation is something we want to see. In order to increase the number of recessive mutations in a population you back-cross the plants (breeding a daughter plant with a parent plant), or force inbreeding (forcing a plant with the gene to pollinate itself; sometimes this isn't possible in plants). After enough generations, which can be anywhere from 10 to over 1000 generations to get a pure line, you have a plant that shows only the allele you want expressed. Most garden plants are created this way; you back-cross over a certain number of generations until you get the desired effect in nearly all seeds grown. A huge downside of this type of selective breeding and back-crossing is that you're decreasing the genetic diversity in a population by selecting the alleles you want expressed and eliminating all others. For most plants this isn't a big deal; the ones grown in gardens are hardly reflective of the population as a whole in most cases, and if a virus or fungus or bacterium evolved that could eliminate an entire population of ornamental plant because of the inbreeding and a lack of resistance it wouldn't matter much. You would replant the next year with a different variety and hopefully the problem is solved. The big problem occurs when we start doing this with crop species, as we have been doing for over 12,000 years. Corn, for example, is so susceptible to disease that it is completely unable to survive without human intervention (not to mention we have eliminated the corn plant's ability to disperse its seeds; this is a slight problem if you're a corn plant but a major benefit if you're a human wanting to eat corn seeds). Soybeans in North America right now are on the verge of a massive population collapse due to the fungal disease called the soybean rust. It has recently shown up in the southern United States and is attacking soybean crops that have all shown to be susceptible to the disease. We grow the same variety in Canada (bred to have an increased seed size with an increased oil store in the seed), but are only saved from the attack of the pathogen due to our much colder winters that the fungus can't survive. It's only a matter of time before an entire year's crop is wiped out which could be absolutely devastating to the North American economy.

The previous blog post I did about this plant (which you can read about HERE) mentioned the smell of marijuana that this plant supposedly has, and the drug busts that have occurred as a result of people innocently growing moss phlox and having the smell waft in the wind. I did pick some leaves and crush them up; if you use your imagination I guess it smells like marijuana. I have a hard time believing that it would produce enough of a scent to convince someone there's a drug op in their neighbour's back yard, and I also have a hard time believing that someone would mistake the smell of phlox for the smell of marijuana!

The creepy, sneaky bellflower

Species name: Campanula rapunculoides

Common name: Creeping bellflower

Location: Ontario

The creeping bellflower is a species of herbaceous plant native to Europe and western Siberia. It was introduced to North America about a century ago, and it has become highly invasive since then. It is a ground cover plant (or growing upwards to a maximum height of about 12 inches) until it encounters something upright (either living or an inanimate object, although it prefers other plants), and then it climbs upwards to grow on top of the surface of the other plant (or up a fencepost, etc.). The leaves and flowers can become so dense that it will completely strangle out the next nearest plant, so is a huge threat in prairie ecosystems. The plant spreads during the growing season via underground rhizomes, and overwinters just under the soil surface. Any piece of the underground stems and roots can grow into new plants, so it becomes incredibly difficult to eradicate; if you have it in your garden, as soon as you till the ground in the spring you make hundreds of potential plants from one former rootstock.

This species was probably accidentally introduced to North America due to confusion with one of its very close relatives, and the species from which the creeping bellflower gets its name, Campanula rapunculus. This second species has been used for many centuries as a food source in Europe, as the leaves can be used in much the same way as spinach. They taste roughly the same, and cook down to a wilted leaf in much the same way as well. To my knowledge, the creeping flower is not edible.

North America's worst perennial garden plant

Species name: Aegopodium podagraria

Common name: goutweed, bishop's weed, ground elder

Location: Ontario

This species of plant is native to Eurasia, likely somewhere near Estonia, Lithuania, etc., and it gets its common name from the superficial likeliness of the leaves to elder. This doesn't speak to the relatedness of the two plants, however; ground elder is actually most closely related to the common carrot! This plant is incredibly invasive, and if given the opportunity will completely strangle out any native ground cover over a vast area. It reproduces underground through the use of rhizomes, produces seed (if conditions are right) that contain inhibitory chemicals to other species' seed germination, and produces such dense, thick growth that no other plant can grow up through it (and thus inhibiting the germination and growth of tree seedlings). It is also very resilient to shading by other species, and can grow up through a variety of soil covers (gravel, woodchips, mulch, and sometimes even that gross horticultural fabric some people put down to inhibit weed growth). Many countries have labeled this plant as the worst perennial garden plant, and some have even banned its sale.

So is there anything good that can be said about this plant? Well, there are three different species of moth and butterfly that use this plant as food for their larvae, but it's not their exclusive food source so an alternative that is less toxic to the environment in general can be found. It was historically a popular source of leafy greens in the Middle Ages (the young leaves; the older leaves have a somewhat laxative effect and should be used sparingly if at all), and has been used medicinally for hundreds of years (hence its other common name, goutweed). Monks in England used this plant in a warm wrap to treat the effects of arthritis (and hence it's third common name, bishop's weed).

The Master of the Woods

Species name: Galium odoratum

Common name: woodruff, sweet woodruff, wild baby's breath, master of the woods

Location: Ontario

This photo doesn't quite do this plant justice; if I find another one hidden in my plant photo folder somewhere I'll post another to show size and perspective. This plant is native to Europe, the Middle East and/or Asia (depending on who you ask or what literature you consult -- in any case it's non-native) and there's a reason why it's sometimes referred to as the "Master of the Woods" in North America! It's incredibly shade-tolerant, often setting more seed (which are in the form of burrs; my cat hates this plant, as do most deer) in the shade than the parts of the same plant in the sun! It can spread through the simple action of raking up the stolons (very similar vegetative organs to rhizomes, except they're usually above-ground and have very little nutrient storage) and leaving the plant pieces on the ground, or even just running the whipper snipper along the edge of the garden to "edge" the plant. It will re-root and regrow, making it a very effective spreader. It measures only about 10 cm off the ground at its tallest, so is an effective (and very popular) ground cover.

If you've ever seen this plant in person, you know what kind of smothering ability it has so it should be no surprise it can out-compete native ground cover plants for resources. I haven't read anything specifically stating this plant is a noxious weed, but it sure should be considered one! I would argue it's boring enough that if it was banned as an ornamental plant in North America no one would miss it. Well, that's if you could get rid of it in the first place -- I've been trying for a few years on a small patch in my back yard and it seems every time I pull a chunk out it's back in a couple days with more dense growth. I wish you luck if you planted this as an edging plant then decided later to re-landscape!

As for non-ornamental plant uses, this plant has many. It is a great source of coumarin (the contributing chemical to its intense odor; NOT to be confused with the drug "coumadin," they are not the same thing!), which has been used in perfumes since the late 1800s. It is also one of the leading chemicals in "organic" rat poisons, since rats metabolize this chemical into something that causes massive internal hemorrhage and death. Pleasant! Humans do not have this metabolic pathway, so you don't have to worry about it causing massive organ failure if your child (or pet...unless you have pet rats) accidentally ingests it. The effect on other animals is one that has been investigated by the weight-loss industry to no success: it acts as an appetite-suppressant in many herbivores, contributing to the low levels of herbivory it experiences in the wild. Humans don't seem to be as receptive to this effect, for reasons (to my knowledge) unknown. It has been reported to have anti-HIV, anti-tumor, anti-hypertension, anti-arrhythmia, anti-inflammatory, anti-osteoporosis and antiseptic properties and so is currently being researched actively for any major medicinal use. Due to its rather nasty effect on rats, coumarin has been banned in all commercial food products in the US, despite not being as dangerous to humans. It is used in the food industry in Germany, however: it is the major flavouring agent in the beverage "Maiwein" or May wine. It is used in many other countries to flavour alcoholic beverages and alcoholic jellies as well.

Not all Phlox are created equal!

Species name: Phlox subulata

Common name: Moss Phlox, Mountain Phlox

Location: Ontario

The Moss Phlox is a ground cover plant native to North America, with its natural range extending from Quebec to British Columbia and south towards Colorado and Tennessee. I would argue that now in certain habitats (like my back yard) it has become invasive, perhaps because of a decrease of natural competitors in the areas which it now grows. Almost all species of Phlox are native to North America (a few species, or only one depending on your definition of species, are native to Siberia) in some capacity, with overlapping ranges extending from East coast to West coast and from Alaska south to Florida. The variation in this genus of plants is a great example of "niche theory", which states that plants and animals evolved to specialize to a specific niche, and so "microhabitat" can be a leading contributor to the evolution of new species. This theory has been all but abandoned in recent literature in favour of other theories since it could never explain all the variation seen in an area by itself, but it's still a good theory used in conjunction with others to explain species distribution. The genus Phlox contains more than 65 species, being distinguished by their size at maturity (ranging from only a few centimeters tall to over a meter) and their flower colour. Horticulturalists have hybridized various species to produce new and unusual flower colours that would not have been present in large numbers in natural populations.

Other than a popular ornamental plant, Phlox species in general are not used for a whole lot. There are no species with any medicinal value (either historical or current) with the exception of Garden Phlox which is a powerful laxative. This should also suggest that it's a poisonous plant, and shouldn't be consumed! The analysis of the essential oils in the plant done by a lab in Denmark didn't show the plant to have any promise as one containing chemicals previously documented to fight cancer, slow the progress of AIDS or diabetes, etc.

One humorous side-note to this plant is that it supposedly (I've never noticed this phenomenon, but maybe it is not uniform across all species) has a very similar smell to that of marijuana and has caused the "backyard bust" of a few homes in England and the United States after neighbours reported the smell. I doubt the plant itself would be mistaken for marijuana since they differ drastically in appearance!

Thou shalt forget me not!

Species name: Myosotis sp.

Common name: forget-me-not

Location: Nova Scotia

One of the amazing aspects of the Acadia University campus is their arboretum and medicinal plants garden. Tanya and I spent a good couple of hours wandering around a relatively small corner of campus looking at their pond system (with bog, swamp and marsh areas that they had created), their native plant area, and their medicinal plant garden. The medicinal plant section was by far my favourite because it had so many unusual plants, most of which were historically used in native medicine or once used for extracts to treat a specific disease. They even had a wormwood plant, since that was once originally used to treat malaria!

The forget-me-nots were growing around one of the ponds, which leads me to believe this could possibly be the "true" forget-me-not, or Myosotis scorpioides (native to Africa), but there aren't enough identifying features in the photo to be able to tell for sure. The genus Myosotis contains about 50 different species, and almost all of them have the potential to become invasive under the right conditions. Forget-me-nots are popular garden plants in North America, since they are such an effective ground cover, especially in shady areas (which should lead you to believe even more strongly that they're invasive!). I remember planting the "mini kind", as I used to call them when I was 4 or 5, with my mom in our garden at the old house. More than 20 years later we were still pulling the stragglers out of the garden! Since the plants themselves were so short, it leads me to believe it was probably Myosotis alpestris that we were planting, or the Alpine forget-me-not which is the state flower of Alaska. For anyone that's counting petals, this plant is indeed a dicot!

Unlike other spring wildflowers I've blogged about so far, forget-me-nots do not produce rhizomes for underground energy storage. Instead, they have a diffuse fibrous root system so they act as effective erosion-control plants by holding in the soil. This root system is also what allows them to invade riverbanks (also called the "riparian zone") and out-compete native plants. It also produces more seed at a much quicker rate than most of our native plants that grow along riverbanks, which helps contribute to their success as an invasive species.

The origins of the common name of this plant are quite diverse, but I'll share my two favourites. The one my grandma used to always tell me (she had a story for everything...true or not, they were always interesting!) was about a knight in shining armour that was walking by the river with his princess when he bent down to pick her some flowers. The weight of his armour pulled him into the river, but before he drowned he threw the flowers at the princess and yelled "forget me not!" The Freemasons also used this flower as a symbol in the 1920s to not forget the poor and desperate people in Germany. The flower still has tight ties with modern Masons, often being worn as a symbol that those that have died are gone but not forgotten.

Forget-me-nots have been used (and are actually becoming more popular) in herbal medicine around the world as a treatment for chronic nosebleeds and lung issues. I would strongly suggest against the use of this plant for these purposes, however, since they potentially contain high levels of chemicals called "hepatotoxic pyrrolizidine alkaloids," which attack the liver and cause liver failure and can cause cancer. There is conflicting evidence on whether all species of this genus contain these alkaloids, but it's always better to be safe than sorry!