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. The Rutgers weed tool is generally appropriate for my region, and  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.

The Virginia Tech and Virginia Cooperative Extension’s weed identification tool helps you narrow your choices, too, by similar methods. And Clemson University had a weed-identification search tool, too.

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), or most often of all the best one for my region, “Weeds of the Northeast” (affiliate link) co-authored by Richard Uva (below). 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. John Moore says:


    I confess to being an unintentionally evil gardener. Let me know if you have ever been this unfortunate, or simply, just this stupid.

    I wanted a full carpet of forget-me-nots for a shady street-side bed. So, I laid in a thick covering of mushroom compost over my dam’ clay soil. I broadcast thousands of forget-me-not seeds.

    Up sprang my little seedlings. I became suspicious as they grew . . . the sprouting leaves were larger and lighter green than I had expected. But I was determined to keep going with visions blue and white and carmine flowers covering all.

    I faithfully watered through that year’s bone dry summer. As the plants grew taller I realized that I was growing something different . . . but what? It wasn’t until I saw and recognized your headlining picture of garlic mustard that I knew what I had done.

    Yes, I cultivated a healthy patch of garlic mustard! Now, a couple of years later, I still have the penance of pulling the MFers (multi-flowering plants) all over my property.

    I am an idiot.



      1. tim says:

        there is wild garlic mustard all over in my yard naturally….I always mow it, but it is beautiful in its own right. I decided not to mow some that look like a beautifully planted flower! Your story reminds me of my uncle…God rest his soul…..when I was kid of ten back in 71, my uncle planted a bleeding heart. He watered it all the time and boy did it grow. I remember him planting it and tending to it, waiting like you, anxiously expecting a beautiful plant. Lo and behold a month later a beautiful weed bloomed…..don’t know what kind as I was a kid. But he always told everyone about his gardening experience, and laughed about it. You’re not the only idiot. lol

  2. Barbara Drake says:

    Years ago when we moved into our house, the entire yard was covered with aegopodium or goutweed. It was not even the pretty variegated variety. In our quest to start composting, we tilled and composted so much of it that we started a years long battle with the pesky plant. Its roots will survive under three feet of soil and the only way we were able to finally eradicate it was to put black plastic on it for several years. I still see it popping up in places in the thicket near our pond and my heart jumps a beat!

    1. Clara says:

      It is THE WORST…with the possible exception of rampant non-flowering wisteria. I have pulled it, mowed it, black plastic’d and newspapered them…and sent other plants such as hay scented fern and sensitive fern after them to smother and shade them out. Also, to some extent, hosta. It’s pretty effective…not perfect.. but ok

    2. Susan Schmitz says:

      I feel your pain. I had a house years ago where the entire (!!!) yard was goutweed . Pretty, yes, but not my vision for the place. What a nightmare to get rid of . Twelve years later, when we were selling the place, I still had some popping up in places. To think they SELL that stuff in some places. Ugh!

  3. Ann says:

    I love researching weeds. I find them fascinating. Garlic mustard could solve world hunger in my opinion. I just don’t like them growing in my yard! It is a constant battle. Thank you for those great resources. I do the pulling then smothering with cardboard technique. It has really helped in this semi wild part of our landscape.

  4. Lorie says:

    Garlic mustard!!!! I live in a gorgeous wooded area…I USED to live in a gorgeous wooded area! When garlic mustard started taking over the woodland floor, I implored my neighbors to join me in a plan to wipe it out while it was still able to control. I got zero cooperation. “It’s a nice green ground cover,” was the reply of the many who are getting older and don’t want to spend time or money on “problems”. So now it is beyond control, both physically and monetarily, and suddenly people are thinking it should have been addressed earlier. It’s the plastic bag of the forest floor, and I think it’s too late.

  5. karen rodgers says:

    Lesser celandine. Smothers everything. It’s gone wild in the poorly-tended lot next door and is now spreading everywhere in my gardens. So pretty in April, ugly going-dormant in June, and almost impossible to kill. I hate it!

    1. Manugian Liz says:

      Karen, I totally agree that lesser Celandine deserves a place at the very top of the noxious weed list, and it is hardly ever mentioned. And I am not sure why … I just wrote a letter to Margaret asking for any suggestions. If you have any success in eradicating this weed, please let me know!

      1. margaret says:

        Unfortunately this tuber-producing perennial is extremely challenging to tackle (unless just a small infestation that can be dug and dug again till all the tubers and other parts are gone). Most conservation organizations and government agencies that have tackled it recommend chemical methods (glyphosate) in late winter-early spring. An example and another of how different groups are tackling it. One of the worst.

  6. Ellen Johnson says:

    HORSETAIL…and it’s still sold at nurseries and plant sales. unbelievable. unfortunately for me, none of the research i did when i learned that i had horsetail in my yard, warned me about what to do and what never to do. specifically, never try to dig it out or you will only spread it.
    and it would be even better to ignore the fact that you have a yard completely. because if you accidentally step on some or touch some, you’ll unleash all its spores to spread their evil-ness everywhere.

    according to locals, the only way to get rid of horsetail is to move…

    i’m ready to pour concrete over the whole yard – which is a terrible thing for a gardener to contemplate.

    1. S.Lynn says:

      Horsetail Rush (Equisetum) is spreading rapidly along our irrigation banks. It loves the moisture. We’ve tried glysophate mixed with 2-4d and spray it when it’s young before the spores appear but it continues to advance into our grass field. It is unsuitable for horsehay so we’re killing an acre along a ditch for the year to see if we can dry it up. If someone finds something that kills it they’d make bank.

      1. Sheri says:

        It was well established in my backyard, coming under the cement wall from the neighbors but I found that by changing the acidic soil to alkaline helps with lime treatments. Then I planted Sage (the battle line) and noticed the Horsetail disliked it so I make a point of doing an after bloom cut-back and spread the leaves so they release their oils. It only attempts to make an appearance in spring and shows it’s head right after a rain.

    1. ROBIN MCKAY says:

      A friend no more gave me a flowering bush and a stem of bishop’s weed tagged along. Before I knew it the thing had spread to a prized bed and beyond. It lives to be abused and the only way I got rid of it was to cover the area in thick black plastic and cardboard for 3 years!

  7. fred says:

    According to my grandfather’s definition, a weed is something that is growing in your garden that you did not put there. It can be moved to a different place a nd become a flower or plant in that is in it’s right spot.fred

  8. Vicki Carson says:

    Japanese knotweed! Spreads by seeds, but worse can travel yards and yards underground. Chokes out everything else, cracks pavement, and even damages foundations of buildings. Luckily, I have none in my yard. I spend the summer fighting it as volunteer in local park.
    It has pretty white flowers in late summer, but DO NOT PLANT THE STUFF!

    Vicki in Pittsburgh

  9. Lynn says:

    I have common and mouse ear chick weed I have been trying to get rid of for years, With the extra wet and warm winter here is zone 6-7 it is everywhere this year. Does anybody have ideas?

  10. Faye says:

    Wind violets! When I moved here 5 years ago, I thought they were so pretty and a wonderful groundcover. 5 years later they’re everywhere and I can’t get rid of them. They have completely taken over my flowerbeds. HELP!

    1. Diann Wilbur says:

      I have the same issue! I live in Southwest Illinois and saw some white violets with purple inside on a neighbors lawn (so unique) and could not resist. I took a few home and now we have violets everywhere. I had no idea how quickly they spread, not sure how to get rid of since they have roots that travel underground.

  11. Lauren? says:

    Some weeds I know the names of, others, not yet. That does not stop me from bestowing upon them the names I make up for them but I can’t say them here because my parent brought me up right.

    One thing I’ve learned over the years, though, is be wary at plant swaps, since the things people want to get rid of are what often shows up there. In the earlier Inexperienced days I got Gooseneck Loosestrife, the creeping yellow flowered Loosestrife, Variegated Bishop weed, some horrible invasive fern, that Chameleon Plant thing, a horribly invasive Liriope, VIOLETS!, terribly invasive Obedient Plant, horribly invasive Spiderwort!!, RIDICULOUSLY INVASIVE TRUMPET VINE, …OK, I’ll stop now since I’m getting worked up. I did battle with these by ceaseless handweeding and won on everything except the Gooseneck Loosestrife and the Trumpet vine – we had a sort of DMZ. So then I moved and the new people destroyed everything so it doesn’t matter.

  12. kate says:

    Thanks Margaret! Since we don’t use any pesticides/herbicides, I eat most of my weeds…sauted garlic mustard, dandelion and onion greens are a great addition to omlets. Adding violets to a salad are not only tasty but pretty. Enjoying what Spring has to offer – yum!!!

  13. Ginger Cawood says:

    No one has mentioned gill over the ground. This plant sprouts roots all along its vine and intertwines over other plants. I have pulled yards and yards of it, but it persists everywhere, even in plain grass areas.

  14. Liz says:

    I have a rapidly spreading area of lesser celandine. I didn’t mind it when it confined itself to the lower part of my garden. Now it seems to be cropping up in other parts of my 4 acre garden (in the moss lawn, in my perennial beds) here in Memphis and I am very, very anxious to find a way of eradicating it. Having tried it in the past, I know that weeding is not a option since every root seems to have hundreds of bulbets attached to it. I don’t used herbicides because I have considered them to be toxic to the environment and my family (2 legged and 4 legged). Do you have any tried and true suggestions? If I have to resort to herbicides, and a single application would help me get rid of spreading nightmare, I might consider it.
    Look forward to hearing your expert opinion.

  15. Beverly says:

    I like Dandelions, and consider them salad greens, not weeds. Garlic Mustard is another story! For years, I back-breakingly weeded the rampant new sprouts. Bags and bags out for the garbage. I realized my labors were in vain since my neighbors did nothing about theirs.
    It’s something I grudgingly learned to live with, though t’s still very satisfying to yank it from my beds, now and then. I wonder if it has some sort of use or maybe medicinal properties?

    1. Darcy says:

      It’s deliciously edible when cooked, if you don’t mind a slight bitterness (think rapini). We foraged it from the local park all spring long early in the pandemic; now that we have our own yard, it’s simultaneously weed and potential food source.

  16. Ginny says:

    Oh my, what a hot topic Margaret! Save me from bindweed, onion grass, and bitter cress. And I accidentally planted prunella, a sin I’m still doing penance for. We all have weeds that are the bane of our gardening existence if the comments here are any indicator. Good post!

  17. Kay says:

    I hate wild Bermuda grass, aka wire grass, and nut sedge. They almost make me want to use herbicides ( which are also ineffective). When we moves to our current home, we spent an entire summer digging up our front yard and sifting out the broken pieces of wire grass. We then turned it into a raised bed vegetable garden. Slowly, as our backs are less reliable, we’ve turned to native plants. Still we fight the nut sedge and the wire grass.

    1. Jane Chance says:

      I may be commtting an unpardonable sin, but Sedge Hammer worked for me. Have to order it from commercial supplier and it’s not cheap.

  18. Rhea Seeger says:

    No gardener is alone in the fight to identify and deal with unwantables in the garden. When I retired I took on my dream job of working in a local garden centre. I was horrified by the selection of ‘ground covers’ being offered and suggested we quiz the shoppers on where they were placing these plants before purchasing. I still literally crawl through my perennial garden each spring spudding out goutweed that I introduced myself when moving plants from an abandoned farm garden. PS thanks for the weed identifier material. I always thought we needed to identify them from their wee early stages before letting them mature!

  19. Stella Neves Elbaum says:

    Purslane. The enemy I cannot destroy. Don’t tell me to eat it-it tastes like slime. For 8 years, I’ve fought this battle. The hotter and drier the summer, the more they grow. I’m exhausted.

  20. Carolyn Roof says:

    Plants are more important if you know their names. Taraxacum officinale makes dandelion sound so important. If you know its name it is easier to find out how to control and when. Love UC-DAvis showing seedling stage. That is the bet information on weed control I have seen.

  21. Anna says:

    Now that we are not going to the farmer’s market (or grocery store, for that matter) unless absolutely necessary, I’m looking at many of those weeds with new eyes.
    This last week we ate garlic mustard sautéed on pizza, processed into pesto, and chopped up in guacamole. My pandemic meals are full of healthy greens- organic, free, and extra-local.
    It feels satisfying for now. We’ll see how long that lasts…

    1. margaret says:

      Hi, Dana. I suspect when I wrote the piece and searched for online weed ID databases I did not find one for NY specifically. The Rutges one is probably the one to try as a start.

  22. Barb says:

    The first year in my new home, I planted morning glories around a chain link dog pen. As they grew I painstaking helped them twine up the fence. Day after day I carefully tended……bindweed. Ugh.

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