what weed is it? putting names to pesky plants

garlic-mustardI KNOW A LOT OF PLANTS BY THEIR PROPER NAMES, but when it comes to “weeds,” as we term unwanted garden visitors that seem to just come with the territory, my knowledge really pales. So lately, on days not conducive to outdoor work, I’ve been studying up a bit from some great weed-identification websites, so that I can finally address Alliaria petiolata (garlic mustard, above) with the proper (dis)respect.

I didn’t even remember the botanical Latin name for the ubiquitous dandelion, Taraxacum officinale, below, until I became a regular on the Rutgers New Jersey Agricultural Experiment Station “weed gallery” recently. What I love about the Rutgers weed tool, besides its general appropriateness for my garden regionally speaking, is that I can browse by common names or by thumbnail photos (or by Latin names if I ever know one).

dandelion 3
The University of Minnesota’s “Is This Plant a Weed?” tool is another place you’ll find me, narrowing the field of possibilities until I get an ID by clicking through a series of photo-based prompts (such as grass or broadleaf….upright or creeping…and so on). It almost makes weeds fun. (Note the almost.)

Steve Brill, the so-called “Wildman” forager who teaches in Central Park in New York City and elsewhere, has a chart and plant profiles of edible weeds on his website, if you’re hungry, though you’ll have to scroll a third of the way down the homepage and click on “wild plants” (fourth blue box from the top) to get there. Once you do, you can serve up Japanese knotweed, dandelion greens and even plantain (though the latter’s not so tasty, below; Plantago major is better used on mosquito bites than on a dinner plate).

The University of California-Davis weed ID site is encyclopedic, and though I wish I could sort by images, once I get to them (on the plant profile pages) the information is some of the most detailed anywhere. They even show the weed in its seedling stage so you can eradicate it then without wondering if it’s your beloved self-sown something-or-other. See what I mean on a sample page (this one is bedstraw, Galium aparine, a common weed here as well).

With 172 species included, the University of Illinois has built an extensive weed database that’s browsable by common or Latin names, but with the added feature of filters (you can sort the list down to a certain flower color, for instance, or one of a series of very specific taxonomic keys, like leaf size, width, or the arrangement of the leaves. This one will get you sharpening your powers of observation.

I own a number of weed guides, some more booklet-sized than book, and was happy to find a full-color one posted free online. “Weeds of the North Central States” is available as a PDF to “page” through, should you happen to live in them there states.

Want to know which ones are so bad they have made their names on the state-by-state “noxious weeds” lists? The real Bad Boys of Weed-dom.

As many weeds as there are, there are apparently as many sources to learn about then. I could go on, but then you’d think I’d grown a bit obsessed with weeds at the moment, wouldn’t you?

April 21, 2010


  1. Ellie says

    The bane of my garden is Glechoma hederacea, aka ground ivy or “creeping Charlie”. I will dig out a huge patch of it and it’s back within weeks.

    Of the weeds I actually planted, I am guilty of inflicting Blue Fortune agastache and chocolate (white flowered) Joe Pye weed all over my garden.

    And then there are the wild violets. Everywhere!

  2. Rae says

    I am so happy to find a weed which has spread in my front garden – buckhorn plantain. It faked the stokesias I have there perfectly until it flowered. I can now see the babies which are like a small lettuce. Thanks for the Illinois list link, Margaret.

  3. says

    Thank you for the id of clearweed on another post. It is in my garden, too, and was driving me nuts that I couldn’t name it. (I do so understand your desire to identify your weeds.) Since there are over 100 comments on this post which I’m not going to read through, I may be repeating someone else. But I wanted to share two other weed identification sites I’ve found: http://weedid.wisc.edu/weedid.php and https://gobotany.newenglandwild.org/advanced/ . Thanks!

    • margaret says

      Hi, Kathy. Yes, clearweed as a familiar resident here for years before I figured out who it was! Thanks for the added sites to search.

  4. Kathy says

    Yes, the id of clear weed is very helpful,. And as do many of you I have lots and never knew what it was.
    Be gentle with the “weeds”. Many of them are helpful herbs.

    • margaret says

      Agree, Kathy — important to leave enough for pollinators and other insects, but not in the beds where you are growing vegetables or formal areas, of course. I like to have rough, unmown areas of the yard that support wildlife where anything goes, contrasted against the more “garden-y” beds and borders.

  5. Shelley says

    Is there a comprehensive pictorial on weeds? I have what I think is pig weed plus some other nagging problem weeds but am unsure what they are and, therefore, how to deal with them. What would help a lot are pictures of all weeds in my area (Pacific NW, Eastern Oregon).
    This weeds grows along the ground and has red stems. I think it’s an annual.

    Your blog is the most reliable source on so many things that I come to you for help. Help! :)

  6. Julie Pierce says

    I was amused to see forget-me-not, one of my favorite flowers, on the Massachusetts invasives list. Yes, it spreads aggressively, but who can resist those adorable bright blue flowers?

  7. Margaret says

    Every year I discover a new problem plant.

    Last year it was pokeweed. Native at least, and the birds love it, but it makes giant tubers that are a PITA to dig out and it came up evvvvvvverywhere.

    I have ragweed of some sort (I think) which spreads by runners and seeds. I don’t know if I’ll ever get rid of it.

    I spend a lot of time and effort trying to get bermuda grass out of my garden beds.

    This year, I found an invasion of ranunculus repens, or creeping buttercup, in my shade garden. It was all over my hellebores. Wicked stuff.

  8. Brigitte Frank says

    I used to pluck all kinds of weeds out of my lawn, esp dandelions, but no longer. Dandelion is one of the first source of food for honeybees. They aren’t that bad looking and I do add them to salads, as my property has been organic for 11 years. No, I don’t have the greenest perfect lawn on the street, and I”m OK with that.

  9. Sharon says

    I have been picking dandelion and garlic mustard leaves to add to salads.
    The first live greens to celebrate winter finally going away….

  10. Jacquie says

    I know Spiderwort isn’t a weed but I think it should be considered as such. This “plant” shouldn’t even be sold! It should be treated as a weed, aka a nuisance. They pop up all over and the new sprouts can’t be pulled as they break off at the ground. Round up does the trick but I hate using it. The little purple flowers look like violets and are quite nice but……..not worth the trouble. Does anyone know how to get rid of this plant? We dug it out but the new shoots continue to pop up :(

  11. says

    Thank you so much for sharing this useful information. There are many plants and weeds here that I’m not familiar with(I’m originally from England) so this is treasured information! Especially when my usual reference (my other half) is away and I have to clear the undergrowth beneath the fruit trees. I’m so glad I stumbled across your blog a few days ago!

  12. says

    Today I found a Bloodroot hiding near my Forsythia. I was delighted as I do not have them in my area as far as I know and had planned on buying some. So sweet and much smaller than I expected. I transplanted it to an area I am developing into a white garden near a white bleeding heart in the shade of an apple tree.

    Yesterday near the edge of my brook I found a new pretty yellow flower a little larger than a buttercup and after searching found it was an invasive lesser Celandine http://www.invasive.org/eastern/species/3069.html So I will remove it. What makes a plant a weed? Something with a thug like nature that overruns other plants. I would transplant a flower seedling from one place to another, but not a weed. I WILL plant weeds if they are important for wildlife. I leave the wild privet hedge plants growing with wild roses through them in the edges of my property in the woods for the birds. Cardinals and others are darting through them right now looking for the perfect place to make their nests. I do cut and wrangle out bittersweet vines and wild raspberries that seed and grow everywhere within the shrubby woods. No matter how much I pull out, there will always be enough for wildlife to eat. Now if I could only find a blackberry patch…

  13. june says

    i could do without cheatgrass and russian thistle….in my previous house, I had tons of that garlic mustard. Always a weed, no matter where you are! LOL!

  14. says

    I found Catchweed Bedstraw (Galium aparine) Under the name Cleaver in an herb book.
    It has the name Sticky Wicked in our area. Trying to be more correct I changed to calling it Cleaver Weaver.
    As the UC reference you gave says it grows in disturbed ground which I try to minimize so it gets its start on the edge between the mulch around my berry vines and the grass pathways.

  15. Diane says

    Although some of these weeds are pretty and edible
    There are some I would like to get out of my lawn
    Any suggestions- especially the violet!

  16. Cole says

    Thanks for the great posts regarding weeds. I have a new issue that I’ve never encountered before. This spring, my garden looks as if I had sown hundreds of green onions. I don’t plant vegetables, I only grow perennials, roses and ornamentals. I do have a number of Alliums, but remove the seed heads. Each one looks like a green onion – do you have any idea what this might be and how to get rid of them? Do you think a neighbor’s allium seed could have invaded my garden?

    Any advice is welcome – thanks!

    • Helen Malandrakis says

      I planted choc. Joe Pye weed, and it would wilt and dry up every year, shortly after it bloomed. I finally, dug it up.

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