If I had a nickel for every “weed” I pulled when I first started gardening, I’d have enough money to buy a lot more plants. Looking back, I wonder how many of those plants were actually weeds at all. Really, how do we recognize if something is a weed? How do we control them, or do we need to control them?
Weeding out a definition
We all define a weed slightly differently and that kind of nuance can make it difficult to convey what we really mean or want. My garden is according to some a ‘weedy mess’ to others a native pollinator haven. There are three official definitions of a weed:
A weed is any plant growing where it is not wanted. – USDA, Weed Science and Management
The term ‘weed’ means different things to different people. In the broadest sense, it is any plant growing where it is not wanted. – US Bureau of Land Management, About Weeds and Invasive Species
The term weed is commonly used in reference to any undesirable plant or a plant that is out-of-place. – OSU Extension Office, Weed Control on Rangelands
The key takeaway here is ‘out of place’ and ‘not wanted’. For the gardener anything but garden vegetables and flowers are weeds. That’s not really an approach I would want to take. So how do I decide whether a plant should stay or go?
- Is it harmful to me or my plants?
- Does it spread aggressively and take over my garden?
- Am I helping this species spread where it doesn’t belong?
I generally view these questions in this order. For example, is this harmful to me or my plants; occasionally I get a poison hemlock plant in the garden. I remove it so that I don’t get it mixed with my early carrots or accidentally get the plant toxins on me. Next, does it spread easily; I remove Johnson grass from my garden because its a non-native, prolific seeding grass. Finally, am I artificially ensuring its survival which may be harmful to the native environment; this as always is a little harder to define but take Deadnettles for example. These small plants with their bright purple honeysuckle-shaped flowers are in almost every yard and playground. They are not part of the native tallgrass prairie plant community. They don’t bother my garden plants but by allowing them to grow in my garden I’m harboring an exotic species that can spread quickly.
When I first started gardening, every unfamiliar plant was a weed. If it wasn’t something I had planted, I assumed it didn’t belong. Over time, I realized many of those “weeds” were native wildflowers, volunteer trees, or beneficial plants that were simply growing in unexpected places. That changed how I approached my garden.
Identification
Identifying plants isn’t always easy. I usually start with Google Lens to narrow the possibilities, then verify the identification with iNaturalist and the Lady Bird Johnson Wildflower Center. Google is surprisingly good, but it sometimes mistakes poisonous plants like poison hemlock for harmless relatives such as Queen Anne’s lace or wild carrot.
Using iNaturalist to compare your guessed species against what other people have found in your area (or ecoregion) can really narrow down a search. As an example, I was looking at a plant near Keystone Lake. Harmless as it was Google told me it was Poison Ivy. Growing up in the country I knew it wasn’t, iNaturalist also assumed Poison Ivy but also offered Box Elder. I could then determine it was in fact a young Box Elder tree.
It takes time to really identify a plant. I’ve spent most of my life learning to identify plants, and only in the last few years has technology made that process much easier. Even so, no app replaces careful observation. Ive tried to create cheat sheets for plant ID but the variation in time of year, colors and in some cases environmental effects alter the plant look.
iNaturalist, Google and Lady Bird Johnson Wildflower Center all help the identification process. People make mistakes and Ive pulled plants from my garden that had enjoyed the area for months prior after I discovered what they really are. I don’t rely on social media for plant identification. It’s a good place to gather ideas, but I always verify an identification using university resources or multiple reputable references before making decisions in the garden.
Reflection
Today I rarely pull a plant until I have some idea what it is. Sometimes it is a weed. Sometimes it is an invasive species that needs to be removed. Sometimes it is a native wildflower, a volunteer tree, or a useful plant I simply did not recognize.
That is the hardest part of defining a weed. It is not always about the plant itself. It is about where it is growing, what it is doing, and whether it belongs in that place. Discovering that a plant I once thought was detrimental can actually benefit my garden is rewarding in itself.
For me, the first step in weed management is not pulling, spraying, or covering the soil. It is learning to identify what is growing there.