Teasel, Dipsacus fullonum, Once an Important Tool

Teasels, Dipsacus fullonum and Dipsacus sativus,  in the teasel family, Dipsacaceae, for centuries were essential to the clothing industry. Today, in North America, they are noxious weeds.

teasel showing the seed heads

Plant Story--Colorful Common Tansy, Tanacetum vulgare

Tansy is a small plant with bright yellow flowers and a spicy smell (scientific name, Tanacetum vulgare sunflower family, Asteraceae). It is native to western Asia but long ago became an herb and spice that was grown throughout Europe and then transported by Europeans all over the world. Today we know it more as a garden flower or roadside weed than as a flavoring or medicine, but it is all of those. 

common tansy, Tanacetum vulgare

Western Nebraskan Plants Easily Seen At Cedar Point Biological Station

Recently at the University of Nebraska's Biological Station, Cedar Point, at the Station's 50th anniversary, I failed to take very many photos of buildings and people. Here are a few of the photos of plants I took, instead.

buffalo burr, Solanum rostratum

For example, buffalo burr (Solanum rostratum, tomato family Solanaceae). Native to North America, it gets its name from its presence in areas denuded of other plants by bison, and since then, by cattle.This big-flowered plant has impressive spines (look next to uppermost flower in the photo above). The burs will stick to animal hair, dispersing it.  It is also rich in alkaloids that deter insects. It is one of the American plants that has gone around the world as a weed. Okay, it is hated around the world, but it is nevertheless a plant success story. Look and don't touch. 

Our Natives are Weeds

 "We have a marketing failure with natives," Doug Tallamy wrote in Nature's Best Hope. While I think the "grow natives" movement is helping correct that, the fact that many natives are called weeds does discourage loving them. 

fireweed, Chamerion

Lots of our native plants are weeds. That is, they have weed in their common name. Fireweed (Chamerion), milkweed (Asclepias), jewelweed (Impatiens), Joe Pye weed (Eutrochium), and ironweed (Vernonia) to name a few. 

Plant Story - Flixweed, Tansy Mustard, Herb Sophia, Descurainia sophia, Weedy Spring Mustard

 As a group, the plants in the mustard or cabbage family, Brassicaceae, are cool weather plants, growing well early in the spring, flowering as the temperatures warm, going to seed in the heat of summer. Familiar mustards are cabbage (Brassica oleracea), broccoli (Brassica oleracea), and mustard itself (mustards are species of Brassica, Rhamphospermum and Sinapsis). These edible mustard family plants were domesticated in Eurasia and they are a small selection of the more than 3,700 species worldwide. North America has 634 native species in the mustard family. It also has more than 100 exotic mustards. 

Flixweed, Descuriania sophia

the plant this blog is about 

Plant Story -- Common Mallow, Malva neglecta, Edible Minor Weed

 You stop for a moment: what is that pretty white flower? 

common mallow, Malva neglecta

Then you look down and think, "oh just a weed."

Plant Story--Pretty, Aggressive Creeping Jenny, Lysimachia nummularia

 Some places in the U.S., creeping Jenny (Lysimachia nummularia, primrose family Primulaceae) is a weed, some places a ground cover. 

This is a low spreading plant with pretty round bright green leaves and yellow flowers. It is perennial and evergreen. In my yard it makes a nice ground cover in the shade without being particularly aggessive. In much of the U.S., though, it grows much better, making it a weed.

Garden Thoughts: Who Are All These Plants?

This spring I've been gardening daily. My current Garden Concept is a space of native plants, that welcomes the insects that eat them and the birds that consume the insects. But I like plants, so I have no intention of digging out the peonies or lilacs, even though they support very few native insects. With that complex approach, I took a look at my garden and discovered it was even more complicated.

Plant Story - Horsetails, Equisetum species, Doing Just Fine

Horsetails are odd enough that long ago when I knew very few plant names, I saw one and asked "what is this?" The hollow jointed stems are not like much of anything else. I learned not just that it was a horsetail, but that its an ancient plant. My college textbooks spoke of fossiles from the Carboniferous, 300 million years ago, that are virtually unchanged in structure; the genus Equisetum might be the oldest surviving genus of plants on earth. There were horsetails 60 feet (18 meters) tall. Today there are still some in Mexico and Central America that grow to 20'. Wow. 

Equisetum, horsetails

Plant Story--Wild Lettuces, Lactuca species, Common and Widespread

Garden lettuce, Lactuca sativa (sunflower family Asteraceae) is just one of about 125 species in the genus. (See earlier post on garden lettuce.) Thus, there are many lettuces, most living independent of humans.

 wild lettuce, probably prickly lettuce, Lactuca serriola

Plant Story--Burdock, Arctium, Burs, Vegetable, and Velcro

Burdocks are plants you recognize for their seed pods or leaves. Oh, they have pretty enough pink-purple flowers, much like thistles flowers, but the seed pods have spines with hooks that stick tightly to clothes or fur, and the leaves are very large.

burdock, Arctium

Plant Story -- Orange Hawkweed, Hieracium aurantiacum

I grew up calling it Indian paintbrush, so when I went west and was shown Indian paintbrush, I was puzzled. Currently, the websites say hawkweed is Hieracium, and Indian paintbrush is Castilleja. No relation between them. So I've learned to call the plant hawkweed. Actually, orange hawkweed, Hieracium aurantiacum or Pilosella aurantiaca.

orange hawkweed, Hieracium aurantiacum

Plant Confusions: the Bugleweeds, Ajuga and Lycopus

Growing in my back yard since I bought the house in 2006 is a plant I only just learned a name for. Its Ajuga reptans, a little mint native to Europe that is used as a ground cover. My friend called it ajuga, and ajuga is used as its common name. Reading about it, I discovered the common name in USDA plant list (link) is bugle. Googling it sends you to bugleweed. 

bugleweed, Ajuga repens

Knowing it as ground cover, I was surprised to find it mentioned as a medicinal plant. 

But searching for more information on its medicinal qualities, I found I was often reading about Lycopus. For example, when I followed "bugleweed for thyroidism" I arrived at an article for Lycopus virginicus.

Lycopus is another mint genus, taller than Ajuga, with some plants native to North America. 

Plant Story--Purslane, Portulaca oleracea, Nutritious and Weedy, Everywhere

Purslane (Portulaca oleracea, purslane family Portulaceae) is a very widespread, common plant. 

purslane, Portulaca oleracea

So much has been written about it that mostly I'm going to remind you to notice it.

The "Ideal" Weed

My major professor, Herbert G. Baker, caused a stir in academic botany in 1965 by publishing a list of the characteristics of an "ideal" weed. Since weeds are not popular, an ideal one is a troubling idea.

What Baker did was to look at the characteristics of successful weeds and reduce them to a list, characters of plants highly adapted to reproducing rapidly under any conditions. No real plant has all those characteristics, but some have several. 

The paper made me look analytically at troublesome, weedy plants...and reluctantly admire their resilience and productivity. Fifty-seven years later, these are still good ideas. 

Thoughts on Weeds, Useful Plants, and Wild Plants

Facebook gardening groups post pictures of plants found in their yards and ask "Is this a plant or a weed?" Botanically that is a terrible statement because all weeds are plants, though not all plants are weeds. But what the writer meant was, "Is this a desirable or undesirable plant?" 

We can identify the plant, and if the property owner didn't plant it, then it will likely be called a weed.

But that is so limited! I'd like at least a third category. 

Thoughts While Weeding

We're far enough into the growing season that the bindweeds are flowering and the dandelions are ready for a second round of flowers. I try to weed part of the yard every day. 

One thing I noticed was that although my lawn started the season full of dandelions, my prairie did not. My prairie is maybe 500 square feet that I planted with native grasses and forbs (non-grass herbs) a decade ago. It isn't a great success--some weedy grasses are too common--but I don't water it and my maintenance is confined to weeding out exotics and occasionally cutting back the grasses to mimic natural disturbance such as bison grazing. By the time I got to the 800th tiny dandelion plant in the lawn--an area the size of the prairie--I was struck by the fact that there were only a couple dandelions in the prairie. 

my "prairie"

What does that suggest? 

One deduction is about plant communities; healthy native plant communities are hard for aliens to invade. Not impossible, but much more resistant than most lawns and gardens. (Commercial weed control websites say much the same; make your grass healthy and thick to reduce dandelions.)  Ecologists noticed this pattern long ago and made it into an axiom. But they had to retreat when they found example after example of exotics invading good or pretty good native communities. You can't count on a community keeping weeds out, for two reasons. One is, most of our native communities have at least minor recurrent disturbance from humans (hiking trails!) along which invading weeds can move, little gaps of open ground welcoming the weed seed. Secondly, among all the weeds in the world, there will be one that can invade any particular native ecosystem. The closed community keeps out 99 weeds, but that one gets in. My prairie isn't dandelion-free, but there were only a dozen plants, nothing like the number in my rather neglected lawn. So it is generally true that healthy native ecosystems resist invasion. 

my "prairie"

my bluegrass lawn

The second idea I took from the distribution of my dandelions was about dandelions themselves. We hate them as weeds, but they are plants adapted to lawns and yards, and to moderately disturbed paths and roadsides. They don't grow well in prairies, forests, or deserts. Thus, horrible weeds are a function of both the weed and the habitat. Particular plants are bad weeds in habitats where they grow well, but often they are unaggressive in other habitats. I am growing both creeping buttercup (Ranunculus repens, buttercup family, Ranunculaceae) and creeping Jenny (Lysimachia nummularia, primrose family, Primulaceae) as ground covers. They are not very invasive in my yard. I read about people in Ohio fighting to keep them from taking over. I don't see that. But Colorado is much drier than Ohio, and apparently creeping buttercup and creeping jenny like more rain that my yard provides.

creeping buttercup, Ranunculus repens

creeping jenny, Lysimachia nummularia 

Gardeners are generally aware that environments differ. The USDA Plant Zones define different growing seasons with more or fewer days between the last and first frost, and we know planting a plant in a zone where it is not said to be hardy is a gamble. Gardeners in Colorado are very conscious of the water requirements of plants. Here, if the plant likes it moist, it will likely die if not given substantial supplemental water. Plants with medium water requirements do okay, but rarely thrive. The plants that like it dry or very dry are the ones Coloradans can count on. And then there is drainage. Some plants flourish in a periodically waterlogged soil, others don't grow well unless the soil is well-drained.

We put these ideas together for the seeds and plants we buy, but not so often for the weeds that trouble us. The aggravating weeds are the ones for which my yard has their favorite combination of growing season, water, soil, shade, etc. My neighbor's shadier yard will favor slightly different weeds. If I removed my trees and stopped supplemental watering, I'd significantly change the combination of weeds I fight. 

early spring dandelion in the lawn

To the degree that yards across the U.S. resemble each other, with Kentucky bluegrass (Poa pratensis, grass family, Poaceae, originally from Eurasia) and the the growing conditions it likes, we all share the weeds that also like those conditions

Alas, for all my wisdom, I will still have to patrol my lawn, digging out dandelions, pulling other weeds. 

another dandelion!  --between the flowerbeds

But my conclusion is also that there will always be weeds. If dandelions suddenly ceased to exist, some other plant would take over the spots the dandelions vacated. And, "be careful what you wish for." Dandelions are hard to kill, but they are not spiny or toxic and can be eaten if you are ever in a famine.

Comments and corrections welcome.

Kathy Keeler, A Wandering Botanist
More at awanderingbotanist.com
Join me on Facebook: https://www.facebook.com/AWanderingBotanist

Weeds Can Have Beautiful Flowers

Walking in Boulder (earlier blog), many of the "wildflowers" were European species that have become naturalized in the U.S. Some are sufficiently common to be recognized as weeds. And yet, they can be beautiful.

Suppress your attitude toward these plants and notice them as flowers,

purple salsify, Tragopogon porrifolius (sunflower family Asteraceae)

Plant Story - Aggressive Canada Thistle, Cirsium arvense

 It is not from Canada, though you can find it there...

The plant we call Canada thistle, Cirsium arvense (sunflower family, Asteraceae) is from Eurasia but has spread all over North America. I was amused to see that Canadians call it Canada thistle, too, though official sites in Canada prefer creeping thistle or field thistle. In Europe it is usually called creeping thistle, a good descriptive name, and also corn thistle and field thistle. 

Plant Story--Cutleaf Vipergrass, Black Salsify, Scorzonera laciniata

Right now, in Colorado, Wyoming, Utah, and New Mexico, cutleaf vipergrass (Scorzonera laciniata) is flowering. 

cutleaf vipergrass, black salsify, false salsify Scorzonera laciniata