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 paled until recent years. Lately, on days not conducive to outdoor work, I’ve been studying up 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 plant profiles of edible weeds on his website, if you’re hungry, with Brill’s advice 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.

Likewise, the Integrated Pest Management website of the University of California has a great weed reference database.

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 sample PDF to “page” through, should you happen to live in them there states, and you can buy the whole thing for $5 here.

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.

weed bookAs many weeds as there are, there are apparently as many sources to learn about then, and if it’s old-school you want–with a full-fledged field guide at your side–I use this one (above). I could go on, but then you’d think I’d grown a bit obsessed with weeds at the moment, wouldn’t you?

some of my first-name-basis weeds, and control ideas

  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!

    1. cindy lang says:

      WAIT…these posts are from 2014…is this a recycled post? Weeds? or natives? DO NOT PULL or HARM NATIVE plants

  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. Kathy from Cold Climate Gardening 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!

    1. 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.

    1. 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.

    1. Kristen Oberhauser Bishop says:

      Agree about leaving dandelions alone! They also pull nutrients up from deep in the soil AND they taste good.

      1. margaret says:

        I dig the ones in prominent areas of the yard, between key beds and such. In the outer reaches, I leave them.

    2. Kristen Oberhauser Bishop says:

      HELP! A friend gave me tansy. It has swallowed my asparagus patch, is in the lawn and several other patches. I can see where I pulled and dragged it in years past. There is a path of seedlings. Last year a dislocated my elbow so they had a year where I was unable to keep them in check.

      My husband is insisting that ONLY chemical weed killers will work. It is spreading to our pasture- I know the picky sheep won’t eat it BUT we don’t want it taking over. I was able conduct experiments last year. Boiling water worked very well. I hoed ( that was not fun) and made a path ,which I covered in cardboard in the asparagus bed, that was tansy free this year. I sprayed with soap and vinegar which did not totally kill a large patch but weakened it. Small plants were decimated. I am looking for 20% vinegar.

      I am figuring I will need a three pronged attack. 1. Around plants I cannot move I will pull up the tansy and mulch heavily. 2. Large patches will get sprayed with 20 % vinegar. 3. Beds that can be redone- I will remove plants of interest, harvest leaves ( they are insecticidal so I should use them-right?) vinagarize (maybe even boil them), mow close and then smother in black plastic. I am even thinking of smothering the edges to get any spots where they have wandered away- ok it’s also an excuse for a bigger garden, I admit.

      Any steps anyone would add in to eradicate this evil plague- please add. I live in Maine – so cold winters ( in case it matters). Think I can smother by the end of the summer? I have a broad fork that my husband made me. It helps a lot. ( You want on, Margaret ?)


      1. margaret says:

        I am assuming you mean Tanacetum vulgare, not the so-called tansy ragwort, Senecio jacobaea, which is a noxious weed in some areas in its own right. I don’t think the acetic acid will do much to the roots, and remember: You need to wear full protection when using that hazardous acid. It is labeled for use with professional gear on — not just out there without proper coverage.

  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 :(

    1. Tom says:

      Glad to have read your post. I have spiderwort in my garden ( and probably supported its spread years ago because the early morning flowers were beautiful blue), but have come to realize how aggressively it grows and spreads. So now I’ll be more determined to limit it, though I’m sure never completely. The (dark) good news is that when I must give up gardening, it will be only a very short time for Japanese knotweed to completely take over– many seedlings from neighboring lots pulled each year, and this in turn will be overrun by cottonwood trees ( many seedlings pulled this year). Sadly, I suppose this is the way it goes.

  11. EmsyDoodle 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. 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. Qberry Farm 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!

    1. Anne Furr says:

      We call them wild garlic. You can dig them up but you need to get all of the little tiny bulbs that are attached to the main bulb. They are very difficult to impossible to kill. Good Luck.

    2. 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.

  17. Chella says:

    The University of Illinois weed database is such an amazing tool that comes in handy especially for people like us who love to keep our gardens in the backyard or even the front yard weed free. This is very commendable and am definitely sharing the link with my friends. Am certain it will help them identify weeds as early as possible and get rid of them

    1. margaret says:

      Glechoma hederacea, a.k.a. creeping Charlie or ground ivy, a mint family relative (which tells you something right away about how invasive it can be). I didn’t know for years that besides its formidable runner system, ground ivy also seeds around—so mowing close at flowering time will help in the battle. So does pulling the runners after a rain (or after watering first), then mowing short to reduce any remaining foliage and potential flowers, too. I know it sounds crazy–hand pulling–but if it’s not everywhere yet you can make a dent. I just spent part of a day doing just that in the worst spots here. It likes moist/shady areas most. Here is a simple “IPM” (least-toxic) approach to its management.

    1. John says:

      I have found a four year approach to Garlic Mustard eradication. You absolutely MUST get all the root not just break it off at the surface. I find the best time to do this (at least in southeast Pennsylvania is in very early Spring as soon as the soil is thawed enough to pull the plant. Grab the plant right at the ground just below the crown that is above the ground and very gently pull. If you wait too long and it starts to flower you MUST put the whole plant in a plastic bag and dispose of it. Any flowers even after pulling will seed just as Dandelion does. I have been able to recognize the sprouted seeds in early Spring. This is next years flowering plant. It is very easy to eradicate the seedlings as they do not put their roots down into the soil right away and you can easily disturb them with a small rake or even your gloved fingers. I have been able to almost totally eliminate this weed after it took over our wildflower bed about 6 years ago.

  18. Kari says:

    As our consciousness expands about what we need to leave wild if we want the strength of the wild at our backs, identification is such a wise place to start. Thanks for leading by example.

  19. Kari says:

    I just used the Illinois weed ID database you recommended to identify Red Sorrel, multiplying quickly in a wild area outside my garden and crossing under the fence. I caught it just as it was going into flowering, but it has a wooden, brittle, rhizotomous root system that I suspect will prove a challenge. But at least I have the ID. Thank you, Margaret, for being such a generous, sharing, resource for all things gardening.

  20. Frank Tomeo says:


    Is Galinsoga weed the same as ” smart weed”? Here in KY it grows profusely under the shade of some deciduous trees where I planted pachysandra, and vinca. Vinca either didn’t flower or never made it. This smart weed has a small light purple spike.
    You can pul it out quite easily but it grows back quickly and can smother other plants, and it’s prolific!

    1. margaret says:

      No, I think smartweed is the commo nname for certain polygonums or persicarias; the various kinds usually have wands of small pink flowers. Some examples in the links here.

  21. Sara says:

    I can deal with or eat many of the weeds you mention except for horsetail. I cut it with scissors just below ground level so as not to disturb it’s enthusiastic segmented roots. Any other safe ideas to get rid of it? Thank you.

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