20 June 2010

Exploring the neighborhood nettle patch

Several weeks ago I got restless and wanted to look at something that wasn't comprised of pixels, so I walked down our neighborhood bicycle path to the local middle school's athletic fields.  They abut a farmer's cornfields, and the verge between the properties has a variety of native plants and wildflowers.  I had visited this area frequently a couple summers ago to harvest milkweed leaves to feed our monarch caterpillars, but since our own milkweeds now serve this purpose, I hadn't been back for a while.

On this recent visit, I noticed a patch of differently colored plants at the corner behind the soccer goal.  The photo above shows thigh-high grass at the edge of the field, and behind that some waist-high darker plants in front of the barbed wire.  It looked familiar, so I waded in (after tucking my pants legs inside my socks to keep any ticks on the outside of my pants...)

The plants next to the fence were nettles, which to a butterfly enthusiast can be a gold mine, because they are host plants (food for caterpillars) for at least three varieties of colorful butterflies.  I bent down to take a closer look, and sure enough virtually every plant had holes eaten in the leaves, and more importantly, many of them showed this characteristic pattern (click for fullscreen):

The leaf stem has been partially cut, which causes the leaf to droop.  Then the edges of the leaf have been "sewn" together with silk, protecting the inhabitant inside from predation by critters like the spider (on the outside of the folded leaf), wasps, and parasitic flies.

Now, the question was - could I harvest some of these to take home to raise and release the butterflies?  The first question to be answered was what kind of nettles were these??  There are many nettles, but only two important categories - stinging nettles (genus Urtica) and "false" (nonstinging) nettles (genus Boehmeria).   I'm not knowledgeable enough to know the difference.  If they were false nettles, I could just grab some stems to take home; stinging nettles require a modicum of caution.

One way to sort this out would be to take sample leaves and submit them to the horticultural extension service at the University of Wisconsin and wait for a report.  That would entail a certain expense and would be too slow for my purposes.

The second method would be to get some good photos of the leaf leaves and stems and then consult some plant databases via the Internet.   Less reliable than a professional opinion, but much cheaper and a bit faster.

I took a half dozen photos, then leaned in to snap one of a caterpillar that had emerged from hiding and was climbing a stem.  My camera was set for a macro closeup, but the wind was whipping the plants back and forth, which made the process difficult, and then...


Diagnosis made.  Quickly (instantly), cheaply (free), and reliably (no doubt in the world these were stinging nettles).  Despite the name "Urtica" for the family, the reaction to these is not urtication (itching), but a violent inflammatory reaction manifested by welts:

The pain subsided by the time I had walked home, and the lesions on my upper arm faded that night.  I returned with long sleeves, leather gloves, and 6-inch forceps, and managed to bring back some leaves with caterpillars.  The downside of raising these little fellas is that unlike milkweed leaves or cabbage leaves, those of the nettle are thin and dry out in a day or so.  Combine that with the voracious appetite of the cats, and it means I had to return every two days or so and risk the integrity of my integument to get them more food.

The reward has come the last two days; so far I've released five of these very handsome Red Admirals (Vanessa atalanta):

These are not rare or endangered butterflies; they are actually quite common in all 50 states here.  But it has been an interesting experience to raise them; I'll post more re their life cycle some other time.

Addendum:  Scanning EM of stinging nettle hairs.

Second addendum:  An article at Salon explains how to harvest stinging nettles and prepare them for eating in a salad:
Nettles lose their sting when exposed to concentrated heat, and they are edible and extremely nutritious, being rich in vitamins A and C, as well as potassium, iron, magnesium and calcium... Even though I'm wearing gloves, my childish fear lingers and I can't bring myself to touch the leaves; with these gingerly methods it takes me five or 10 minutes to fill the colander... When it comes time to actually taste one, I hesitate. Maybe just a little longer, I think, and prod the ropey mass of greens for the umpteenth time. I turn down the burner, stalling for time... Maybe it's the aftershadow of the sting, but the nettles taste strangely alive -- fibrous and tingly, with a hard-to-articulate flavor. Nutty is as close as I can get.


  1. Something to remember for next time: crush a stinging nettle leaf and rub some sap on the sting. It's supposed to relive the pain, although I've never tried it myself.

    Stinging nettles are edible. Cooking them removes the sting. They taste somewhat like spinach. I ate stinging nettle cheese in the Netherlands.

  2. In Germany, our back yard and the lots around us were full of the stinging nettles. Ammonia took the sting away almost immediately.

    Watching these posts about 'cats' and butterflies is slowly driving me to wanting to raise them as well.

    Do you have a list of recommended reading on the subject?

  3. I got two forearms of stinging nettles a few years ago in England while getting on my stomach to photograph a small tomb stone. I immediately recalled a nature film I had previously seen depicting the legions of near microscopic needles- but I couldn't remember their origin. When I showed the person I was with my newly enlarged and swollen Popeye forearms, she automatically exclaimed, "Stinging Nettles!"

  4. Painful process, but a beautiful result. I hadn't even heard of stinging nettles until last week.

    We're thinking of planting some milkweed in the back yard so we can see more butterflies up close.

  5. Timeshadows, if you live in Florida, you have a world of possibilities for raising butterflies that those of us in the Midwest would envy. Your choice might depend on what food plants are nearby in your community or your yard or your parks.

    For most people I would recommend starting with the monarch, because milkweeds are reasonably ubiquitous and the caterpillars are easy to work with, and the outcome is a gorgeous butterfly. That's why monarch-raising is a staple activity for so many young schoolchildren.

    Re sources on the 'net, some that you might look at (for monarchs) are MonarchWatch -


    and Live Monarch -


    and this monarch guide -


    and this one:


    For butterflies in general, there is this basic reference source -


    A wonderful resource, and probably the best place to go when you have questions, is the Butterfly Garden forum at GardenWeb:


    You can pop on there as a total newbie and ask a stupid question and get a pleasant, intelligent answer.

    Finally, I would encourage you above all else to look for your local branch of the North American Butterfly Association -


    There will probably be a group or two within a reasonable drive of your home; they will probably have field trips set up that anyone can go on (even nonmembers), and I can predict that the people in the group will be some of the nicest you have ever met.

  6. djinny, there are many kinds of milkweed you can grow. Ignore the "weed" part of the name - these are attractive plants that are not necessarily invasive and are easily controlled in a garden. We grow the common milkweed and the swamp milkweed, with the former in our front garden mixed in with the lilies and other ornamentals.

    You can order milkweed seeds by mail from a variety of sources like this one -


    - but it's also easy just to locate what grows in your area and harvest some seeds and plant them.

    One thing to know is that the plant is perennial and takes a while to reach maturity. The first year your seeds will only grow to ankle- or calf-height while the plant sends down a taproot, and it probably won't flower. The next year it will start up faster and get bigger, and in a couple years it will be full size and blooming.

  7. Minnesotastan,

    Thank you so very much! :D

  8. More info on eating stinging nettles, from a friend's blog: http://outoftheboxfood.blogspot.com/2010/04/steam-and-freeze.html

  9. You have followers because your blog is very good. There's always something worth reading. I'll keep coming back.

  10. An excellent antidote is to rub the sting with some crushed Glechoma hederacea (known by a variety of names, such as Creeping Charlie, Ground Ivy, Catsfoot, Field Balm, and in the Netherlands as “Hondsdraf” = “Dog’s Trot”). It really does banish the pain almost immediately.
    (In my financially lean student days as an undergraduate in Amsterdam I used to eat a lot of stinging nettle soup).
    The two plants often grow together.

  11. Interesting to see all the treatments for stinging nettles. When I've encountered them painfully in northern Minnesota, the "cure" is to jump in the lake and scrub the welts with soap -- with the aim to get the oils (or maybe it's the stings?) off the skin without rubbing them in further. Luckily, unlike poison ivy, nettles can't be spread about by rubbing.

    I know that the sap of touch-me-nots, which grow weedily all over northern Minnesota lakes, are supposed to be good for alleviating mosquito bites and other itches. Perhaps it works for nettles, too.

    As you found, the sting generally wears off within 20 minutes in any case. Not a 20-minutes of pleasure, though.

  12. Grab the leaves from underneath. Being careful about the edges and top. You will not get stung. The spines are on the "oily", dark top of the leaf. Not the bottom.

  13. I was put off by the "weed" in the name. I kept googling images and could never decide if it could be civilized. What is "full size" for a milkweed? What kind of light do they need?

  14. djinny - I'm a little under six feet tall, and our mature milkweed comes up to my chest, so it's about five feet tall.

    In terms of "civilizing" it, the plants emerge in the spring as distinct spikes (very much resembling asparagus, if you've seen that). You can just pull out the ones you don't want. If there are fears by the neighbors that the windblown seeds might colonize their yards/gardens, just wait until after the flowers have turned into seed pods, and then clip those off and discard (or give to another butterfly gardener).

    Re light, I think all milkweeds thrive on sunlight. That's why they grow so readily along roadsides. We have one patch on the west side of the house that only gets afternoon sun, and one on the east side that only gets midday sun, so they can do well in partial shade, but don't try them in a woodland garden or under dense trees.

    I'm trying to grow some in pots to keep inside a screenporch where the caterpillars would be protected from parasitic wasps, ants, etc. Don't know if the pots will accommodate the deep roots of the plant, but I'm giving it a try.

  15. Thanks for all the feedback! We are blessed and cursed with a yard full of maple trees. Sunlight is scarce. I think there is a good bit of unused sunlight by the back fence where they could reach full height without shading the veggie garden. Sounds like milkweed is a good candidate for guerilla gardening, too.

  16. Family Urticaceae genus Urtica genus Boehmeria (but I knew what you meant). I only point this out because I am a botanist and I can't help myself.

    I was just in a swamp whose ground cover had a large component of Boehmeria. There were red admirals all over the place.

  17. Thank you, Darren. Text amended. Your comment about being a botanist reminded me of a line near the end of this Clarke and Dawe sketch...


  18. Anyone know where to get the seeds to grow stinging nettle?? i have M.S. & have bn told it would help!! tks stari

    1. There's a website called "Google." Go there and type in "stinging nettle seed" and you'll have a choice of places to get the seeds.

  19. Nettles are very common from where I come from, it was the chemical warfare of the playground really, the good thing is though where nettles grow you often find dock leaves which sooth the pain



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