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name that weed: pilea pumila, or clearweed

FINALLY: GOTCHA! For decades each summer I have pulled thousands of self-sown seedlings of a plant whose name eluded me, but whose habit and appearance were all too familiar. I’d come upon one stand after another, summer after summer, lurking in masses under shrubs and trees and even under large perennials. But what was its name? And now I know: It’s clearweed, or Pilea pumila, a cousin of stinging nettle (Urtica dioicia) but minus the barbs, and a North American native. A little about Pilea pumila, and about learning to name–and tackle–your weeds. And also why to sometimes leave a little for the native insects to enjoy.

I knew my garlic mustard from lamb’s quarters or mugwort, wild grape from bittersweet or Ampelopsis, oxalis from everything else. But clearweed kept me in the dark longer than most. I could have guessed at its common name, since the stems are practically translucent, or clear. And no wonder I have so much of it: It favors moist soils such as mine generally is, and shady and semi-shady spots in or near woodlands such as the one I garden on the edge of.

The USDA conservation map show the presence of Pilea pumila in 38 states, and parts of eastern Canada. The Flora of North America (efloras [dot] org) says that Native Americans used clearweed medicinally, “to alleviate itching, to cure sinus problems, and to treat excessive hunger.” The Illinois Wildflowers website notes that certain native insects use the plant, too. All these years, the only thing I thought it was useful for? To aggravate me.

Turns out various caterpillars of moths and butterflies enjoy it as a host plant (they’re listed here and include the comma and the red admiral), and so my new policy is to leave a couple of out-of-the-way patches of clearweed to develop at my place. I still pull it from the more formal garden beds.

pull weeds now, or else

I BRING UP A WARM-SEASON WEED like this right now (high summer/early fall) for two reasons: There are probably a lot of them in general in our gardens, and specifically because a lot of them are about to go to seed as in the detail photo above. Pull now, or expect more next year.

My cardboard technique for making new garden beds can also work for weed-control, and I sometimes spot-smother smaller areas when I can’t keep up with the pulling or digging. Pilea pumila, unlike some of my other more firmly rooted opponents, is easy to slip out of the ground without tools, particular after a rain. Place seed-laden or rhizomatous weeds in a large plastic bag first, to cook them to death, before incorporating them into the compost heap.

identify your weeds

KNOW THY ENEMY. After all, how can you outsmart a plant whose habits you don’t even understand? I think success starts with proper ID, and my article on how to identify weeds, including links to many online tools, can help you get to know yours. Don’t wait as long as I did with clearweed; don’t give them the upper hand in garden beds. Again, however, I leave some clearweed on the looser fringes of my property–as I do with another native “weed,” jewelweed.

CategoriesNature weeds
  1. Dahlink says:

    At least this one is a pretty weed. I have something that I have mentally named Gold Thread. It shows up in July and entwines plants in one section of my herb bed, then proceeds to strangle them. Does anyone know what this is and what to do about it? I yanked out all I could find this morning, but I know it’s out there lurking!

  2. Jennifer says:

    Hi…..I have been nursing a couple of plants that I thought were my usual conflowers….turns out they are laterblooming conflower gigantic? mutants. They are not as pretty either. Any thoughts about them.? I dont feel so sure exactly what to do???????? Thank you

  3. Dahlink says:

    Yes, Margaret–that’s it! Dodder for sure. I’ll keep pulling out what I can and hope it stays confined to this one relatively small space.

  4. Lynn Williams says:

    I’ve always wondered what this prolific weed was. It grows everywhere in Southern Vermont including my gardens. Its the easiest weed to pull out thankfully, but the top soil always seems to cling to its roots.

  5. mayapple says:

    Vinegar, Salt, Dawn Solution — BeBe, I’m interested in the formula. Could you please share.

    Have lots of weeds that need “cooking”.

    Thanks.

  6. emm61 says:

    If it’s anything like stinging nettles, it will make a fabulous risotto. I grew up in northern Italy, where the first tender growth of stinging nettles is coveted for such a purpose.

  7. Linda says:

    Can you tell me why when I have succeeded in establishing a dense ground cover…like creeping phlox…do i still have to fight weeds, and worse grass. It just grows up right through it. Any advice??

    1. Carol the Dabbler says:

      Try establishing a groundcover of clearweed instead. There’s a patch at Mom’s house, and my brother (who does the mowing) loves it because it’s attractive and absolutely nothing else grows in it. That’s in moist shade, though, might be different elsewhere.

  8. Deb McDonnell says:

    My plague at the moment appears to be gound elder. If you have any magic potion to clear it, let me know! I use a lot of weeds in my herbal practice for medicine but not the cursed ground elder. I also have a few mystery weeds that I must try to identify. Here in the UK we are finally getting some proper sun; your checklist is coming in handy.

    1. margaret says:

      Hi, Deb. It’s a touch one — I have solarized it to death over a period of years, but you have to take everything else out of the bed of course.

  9. Deb Favero says:

    I have wondered what this plant was called. I almost transplanted some from my woods because I found the foliage attractive but I held off because I didn’t know what it was. So glad I hesitated now. It wouldn’t be the first weed I’d planted…some from the native environment, some from the garden center.

  10. Debra Harmon says:

    I can’t even tell you how happy I am to find out what this weed is! It’s been driving me batty for the past 2 summers. I haven’t been able to find it on any of the invasive plant or weed sites. It has taken over my flower gardens, my lawn, my driveway and even growing up out of the rocks around the foundation of my house, it even survives standing water. Yes, it pulls up easy, but there is so much of it, it’s been a bit overwhelming. Sorry so many other people are having problems with it, but thankful to know I’m not alone! I don’t think at this point, I’ll ever be totally rid of it, but at least I know it’s not poisonous.

    1. margaret says:

      Hooray, Debra — I love sharing my “aha’s” as I know only too well what it is like fighting unknown forces in the garden!

  11. brenda says:

    sweet timing for me to find. the answer… I asked everybody this summer… pulling hundreds…. saving few…. nice to know…:)

  12. Kristine says:

    I just came across this post as I was searching for the name of this plant that grows in a shady wildflower part of my yard. I am very disappointed in the way you encourage pulling of this plant. It is a native plant of North America. Unlike Garlic Mustard or Dames Rocket which are foreign invasives, or many other cultivated plants in our gardens, this plant belongs here. Just because it is commonly called a weed, does not mean it is a weed that needs to be pulled (like the Milkweed that our Monarch butterflies depend on). It actually makes a lovely groundcover for shaded areas. It grows happily with native ferns, native geranium, trillium, and May Apples in my garden. All are native plants and I encourage them by pulling the true invasives like Garlic Mustard. Many of our insects depend on these native plants. Please use care when making these posts and encourage people to keep their native plants that they are lucky enough to have growing in their gardens.

    1. margaret says:

      Hi, Kristine. A “weed” is just the wrong plant in the wrong place, when you are making a garden, and if I left all the Pilea that wants to sow here in the garden beds, I’d have nothing else. There is plenty of it around, not to worry! But to cultivate edibles or ornamentals (or other native plants for that matter) you have to decide who gets the space in a garden bed, because a garden is a contrivance, a manmade planting, with deliberate choices involved.

      For instance, poison ivy is a very important native plant that animals depend upon, and that holds the banks of many coastal areas from erosion and so on with its impressive root network. I love it, and would never try to kill it on the roadside edge of my garden, or elsewhere at the fringes. But when seedlings appear in a garden bed, I do remove it manually.

      Same with Pilea’s cousin, the stinging nettle. Love it — in nature, and as an edible, health-giving herb or food. But if stinging nettle wants to be in the middle of a group of hostas in the shade garden, that’s probably not the best spot for it, so I remove it.

      Gardening involves editing, and I edit with an informed hand, keeping balance and the needs of nature in mind.

      1. You inspire me. I am an infant, if not new born gardener and I so appreciate your overview of “weeds”. This morning I was hoping to find a bit of basil in my herb garden but instead found this Clearweed. I tasted it and it is delicious, like a tender lettuce.

        Now I need to add Basil to my shopping list but I am going to pick a bit more Clearweed for salads.

    2. Robyn says:

      Hello,

      I have this plant also and did some research. Apparently it is an important plant for several butterfly species. I’ll keep mine. The flowers are wind-pollinated, therefore they don’t attract many insects. The caterpillars of the following butterflies feed on the foliage of Clearweed: Nymphalis milberti (Milbert’s Tortoiseshell), Polygonia comma (Comma), Polygonia interrogationis (Question Mark), and Vanessa atalanta (Red Admiral). These caterpillars feed on other members of the Nettle family as well. The larvae of a moth, Cosmopterix pulcherimella (Beautiful Cosmopterix Moth), mine the leaves. An aphid, Pseudasiphonaphis corni, uses Clearweed as a summer host, where they suck juices from the stems and flowering stalks. This species is also one of the host plants of a polyphagous leafhopper, Empoasca recurvata.

  13. Santha says:

    Thank you!

    I’ve been pulling Clearweed and wondering about its’ identity since my childhood in a moist woods in Dutchess County. This is the first time I’ve heard it mentioned by name, and it’s good to have it’s relationship to nettles pointed out.

    It is such an easy weed to pull — I have a hard time taking it seriously, but your article gives it the recognition any respectable weed deserves. I will be glad to be able to call it by name the next time our paths cross.

    1. margaret says:

      Hi, Santha. It’s not a really troublesome weed by any means, and I am sure many creatures (some moths, leafhoppers, butterflies and aphids are glad we don’t pull it all, because they feed on it). But when it seeds in a giant patch in the middle of a bed, I do ask it to leave. :)

  14. Willowite73 says:

    I appreciate Kristine’s post about respecting the value of native plants. I grew up on the forest edge in a healthy New England habitat, and our challenge was always keeping the forest and field out of our cultivated yard, I had the feeling many do on this post, that pulling out nature’s plants was a virtuous cause in our little spot of the world.
    Now, living in a Mid-Atlantic state with a very compromised landscape full of invasives and very much lacking any evidence of the historic flora, I am so welcoming to native plants, of any sort, in yard space, flower beds or edging alike! Any little patch of these plants to provide habitat for the insects and birds who rely on it.
    So, I suppose its a matter of perspective. Places that once seemed so likely to regenerate in their historic natural form, are starting to lose their ‘memory’ and are more likely than not to have non-native invaders pop up when a native plant is removed. Since this is the case, I root for natives everywhere, and find it a new state of mind for gardening. How beautiful, to be a diplomatic host to a variety of native plants and learning their part in the ecosystem.
    A quick note to margaret – the stinging nettle is not native east of the rockies. It is a pain (literally!) of a plant.
    Happy gardening

  15. Linda says:

    Pilea pumila is in the Nettle family, and you may want to keep your stands of it, because it is the host plant or larval plant for the Red Admiral butterfly, the Comma butterfly, and the Question Mark butterfly, to name a few. I have been pulling it out until I realized that it is what these butterflies need to feed their young. Eggs are laid on the plants, and the caterpillars eat the foliage until they form their chrysalis, then emerge as butterflies.
    There are a lot of plants that we think of as weeds that are larval food, and if you want the butterflies, then you need to have some room for these plants.

  16. Linda says:

    You are welcome!
    For your readers who are trying to reclaim their gardens and plant natives, I recommend reading Doug Tallamy’s book, “Bringing Nature Home”. It is an essential book for every gardener. (You may already know about him.) He is an entomology and wildlife ecology professor at the Univ. of Delaware, who not only explains about the use of native plants, but WHY they are so important in the health of our ecosystems.
    In one of his latest Spring seminars, he explained, using his voluminous research, just what kind of environment a Chickadee needs to raise its young, how many caterpillars it needs to find for itself, its mate, and the baby birds. The number is staggering(thousands), and if the caterpillars are not available, no birds. Think about that next time someone wants to sell you a plant that “has no pests”. A garden full of a variety of plants supports many beneficial insects, so that spraying for them is rare.
    Garden as if life depended on it.

  17. Howard Andrews says:

    We find this plant growing in low, shaded spots in our woodlot in central Wisconsin. It is a beneficial native plant. After the first hard freeze, it becomes very desirable to deer. Within a day or two, the deer will have stripped every plant we can find, leaving only the stalks. We’ve nicknamed it “deer candy”!

    1. margaret says:

      I have a fence, that keeps deer out, so I have never seen this. Fascinating! It’s a great native “weed” (like the native impatiens we call jewelweed is too, right?) and I leave plenty of it at the fringes here and there and only weed it out of my most visible beds. Deer candy!

  18. Carol Bradford says:

    I’m late to this party. but after reading what you and NYC Wildman Steve Brill had to say, I went out and ate a few new leaves of Pilea pumila clearweed. It is not unpalatable at all. I might try a soup or nettle lasagna recipe.
    Like you, I have an abundance of this plant and pull plenty. I leave quite a lot around the edges because I hope it is a larval food for various insects, although I’ve had no real confirmation of this idea as the research seems to focus on Urtica dioica stinging nettle, a different species and genus altogether.
    Have fun this season! I have visited your garden on a GC tour and look forward to seeing it again.

    1. margaret says:

      What a nice note, Carol. Thanks for the first-hand update. Illinois Wildflowers (a charming website) says this:

      “The flowers are wind-pollinated, therefore they don’t attract many insects. The caterpillars of the following butterflies feed on the foliage of Clearweed: Nymphalis milberti (Milbert’s Tortoiseshell), Polygonia comma (Comma), Polygonia interrogationis (Question Mark), and Vanessa atalanta (Red Admiral). These caterpillars feed on other members of the Nettle family as well. The larvae of a moth, Cosmopterix pulcherimella (Beautiful Cosmopterix Moth), mine the leaves. An aphid, Pseudasiphonaphis corni, uses Clearweed as a summer host, where they suck juices from the stems and flowering stalks. This species is also one of the host plants of a polyphagous leafhopper, Empoasca recurvata.”

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