There is sometimes a blurry line between a flower and a weed according to Angela O'Callaghan:
When I was driving home from California the other day, I had to stop by the side of the road to take photos of some beautiful white flowers. They appeared to be surprisingly big for flowers in the desert, maybe two inches across, with vivid orange centers. I was even thinking I might be able to harvest some seeds, if they’d already formed.
So I pulled over, camera in hand, to get some close up shots.
Indeed those flowers were lovely! When I got close, however, I saw that their foliage was designed to ward off pests – particularly human ones. The leaves were terrifically spiky, and the plant looked to me as if a thistle had crossed with a poppy. When I got back to the office, I hunted through my weed books for information, but it wasn’t listed under any of the thistles. I finally found a picture on the internet.
It turns out that it wasn’t a thistle at all, but actually a poppy. Not surprisingly, it’s a “prickly poppy”, and there are quite a few different species. Unfortunately, the picture I originally found was mislabeled on the site where I was looking. I had to go to the USDA Plants profile website for a real description. If you’re looking for reliable information, it’s one of the better sites. This plant was a Mojave prickly poppy – Argemone corymbosa – which makes sense, given the location where it was growing.
What strikes me as funny, though, was my immediate thought that since it had such thorny leaves, it had to be a weed. Usually, I’m trying to get people to accept that not all weeds are ugly, and some can be downright lovely – field bindweed and salt cedar come to mind.
This case was quite the opposite, and I’m surprised at myself for lumping anything with a thistle-type leaf among the weeds. I should’ve realized something was up when I couldn’t find it in any of my weed books.
When I was teaching a class on invasive plants, someone asked me for a general weed definition. Invasive, noxious weeds are different, since they are so potentially damaging to health, or the environment, or even the economy. However, for common weeds, it’s not such an easy classification. What makes something a weed?
The most basic definition states that these are plants out of place, or plants we don’t want in a landscape or on a farm. Usually, that covers it. There aren’t too many plants that are always weeds. Tumbleweed, Russian thistle, is one of those – but some of the most common weeds can be useful. Take dandelion, for instance. This plant’s a popular food for desert tortoises; and some people make dandelion wine, or even use the root as a coffee substitute. Nevertheless, it’s a weed.
An eye-catching roadside plant is a little harder to categorize. When does a wildflower become a weed? Can a native plant be a weed? I don’t really think so, but there are situations…
At Cooperative Extension’s Outdoor Education Center, we planted a couple of desert marigolds. This is a tough native plant. Those few plants went insane, and we found our backyard was a sea of bright yellow flowers - not what we’d planned. When someone asked if we wanted to get rid of all those yellow weeds, I was a little stunned. Here’s this plant that thrives in a truly inhospitable climate, that produces flowers when most ornamentals look like they’ve been torched, and it’s considered a weed? Technically, it was, and we did pull up many of them, although it didn’t feel right.
My adventure with prickly poppy reminded me that plants, especially wild plants, frequently resist easy categories. Weeds are often situational, sometimes pretty, and might be useful. Wildflowers might be native plants, might be weeds, and they just might be terribly spiny.
For KNPR’s Desert Bloom, this is Dr. Angela O’Callaghan of the University of Nevada Cooperative Extension.