Worst Winter Weeds: Hairy Bittercress
Spring is in the air, little green things are popping up all over, and we all heave a sigh of relief that the blanket of white stuff is finally gone. But beneath the snow that stopped everything in its tracks lurks a hardy, robust little puff of tiny green leaves that virtually grows before your eyes.
(This article was originally published on March 29, 2010. Your comments are welcome but please be aware that authors of previously published articles may not be able to respond to your questions or comments.)
Call it what you will – hairy bittercress, winter bittercress, hairy cress, popping cress – Cardamine hirsuta – is a weed that tries the most forgiving gardener’s patience. Growing worldwide (except in the Antarctic, this genus of the Brassicaceae family numbers more than 150 species, both annual and perennial. The plant is self-pollinating and in bloom throughout the year. It loves moist soil and grows aggressively under those conditions.
As the snow melts, tiny white, pink, or lavender flowers begin to appear. Yes, flowers. This tenacious weed is short-lived, which is good, you say. A life cycle of 6 weeks doesn’t seem like such a big deal. Think again – how many 6-week cycles are there in a year?
One of the biggest problems with bittercress is that, by the time you discover you have a problem, it’s almost too late to do anything about it. The first flowers appear in late February or early March, quickly form seed pods, and mature. If you touch those trigger-happy seed pods, i t’s all over – the pods explode, distributing seeds over an area up to 36 inches around each plant. Those seeds will germinate and begin sprouting with a few days and the cycle begins again, only over a larger area. Small to medium size plants produce about 600 seeds, and larger plants can yield up to 1,000 seeds.
Hairy bittercress is not invasive enough to warrant using herbicides. As soon as new plants appear in February or March, begin pulling them; these are the offspring of the previous fall’s seed crop. Through the season, always pull the seedlings when you see them; they have shallow roots and come away quite easily; however, bits of root left behind are capable of re-rooting under optimum conditions. The key is to get the plants before they set seed, which happens quickly after blooming. Eradicating this weed from large areas is almost impossible, unless you can hoe and remove. Keeping bittercress out of the flower beds is a little easier, but requires diligent hand-weeding to stay ahead of the seed formation. The leaves release a pungent aroma when bruised.
Hairy bittercress is a problem in greenhouses and nurseries, so be sure to clear off the top 2 to 3 inches of soil before planting anything you purchase. Scoop the soil into a plastic bag and dis card. Keep a close watch on newly planted containers, especially those that are positioned near flower beds. The propulsion factor of bittercress seeds can sneak new plants into your containers while you aren’t looking. Hairy bittercress is a real problem near flagstone patios or walks, brick work, or any hard-scaping that has space between the pieces. This weed does not need much to set down roots – even a small amount of sand between two bricks is plenty.
As mentioned before, at least the seedlings are easy to pull.
Spring is in the air, little green things are popping up all over, and we all heave a sigh of relief that the blanket of white stuff is finally gone. But beneath the snow that stopped everything in…
Weeds that shoot seeds when touched
Need help managing weeds popping up in fall?
Yep, it’s that time for cool season annual weeds to pop up their tenacious little heads again. Among them — Shotweed. It loves our mild temps and gentle, if persistent, autumn rains. Despite being a weed, it can be quite lovely carpeting flower beds in a lovely brilliant spring green. But as lovely as it can be, it is still a weed. So, after introducing a client to it in her own garden earlier this week, I realized it was time to remind all of you gardening readers that this weed is a multi-season menace. As in February when I first posted this article, now’s yet another time to work on clearing it out of your beds. Read more in the original post that follows:
Original Post from February 2009:
One of the many things I do as a garden coach is teach individuals about the weeds in their gardens. Knowing what a weed is and how it grows helps us understand the best ways to deal with the plant. Today, I begin a garden weed blog series, Weeds in Seattle, with a tenacious little plant – Shotweed (Cardamine oligosperma).
Shotweed Rosette Flowering
I decided to start with Shotweed because it is already showing up in tight little flowering clusters all over the greater Seattle area. It seems innocuous until it takes over the garden. I recall in years past telling a neighbor, “As far as weeds go, this one isn’t too horrible. See it has pretty little white flowers.”
Well, shame on me. Letting those pretty little white flowers form and go to seed just meant I was letting this weed get the best of my garden spaces. Sure, we all have to pick our battles in the garden, and we do what we can to stay on top of everything, but knowing that this is a fairly simple weed to remove means I’m going to encourage you to work at keeping it at bay.
Shotweed Seeds Ripening
Shotweed goes by a variety of common names. Shotweed, spitweed, Pop-in-the-eye Weed, Wild cress, Western Bittercress, and Little Bittercress are just a few of the names you’ll hear. The “shot/spit/pop” names come from from poor souls who try to pull it as it has gone to seed. Once those seed pods ripen, the slightest breeze or touch will send tiny seeds flying all over the garden — and right into your eye. The “cress” terms come from those who harvest it as a food crop. Personally, I haven’t eaten it. However, Seattle Tilth’s Maritime Garden Guide (available here) indicates that the stem tips and flowers are slightly peppery. The USDA site says its not palatable to humans. Many other sources discuss it as a good addition to salads. Again, I haven’t eaten it. If you’re going to try it, be sure to properly identify your plant first and try only a very small amount to start and taste at your own risk. Just because one person can eat something doesn’t mean everyone can!
So, what if you just want to get rid of it? Well, you now know that the seeds fire off in all directions if the plant gets a chance to go to seed. So, ideally, you want to remove it from the garden before it sets seed. Unfortunately, for those of us not growing it as an edible crop, this can mean it appears in our cool-weather gardens multiple times a year. This plant likes cool weather. Seeds germinate even in winter, and start appearing in the garden throughout winter. Right now, I can see several of the tight little rosette forms of the plant in my own garden. And, some of them are even putting on flowers. And this has been going on all winter, even though we’ve had cold and freezes. Fortunately, it takes slightly warmer weather for the flowers to transform into seed pods, so we can get out there now get it before this year’s seeds form. Seed formation will be happening easily by March, if not sooner.
So, I’m starting to pull the shotweed plants from the garden as I see them. As a self-seeding annual weed, these plants germinate from seed, form a plant that forms flowers and then seeds. When the seeds are spent, the original plant dies. (There are some perennial forms of Cardamine as well, fyi). And, the plant doesn’t form a deep taproot like you’ll find with Dandelions and Dockweeds, which I’ll cover later in this series. Instead, it is fairly shallow-rooted, with wide tiny roots that are easy to pull. It does have a slight taproot, but nothing difficult to remove. Plus, unlike the taproot weeds, if you don’t get all of the root from a shotweed plant, it isn’t likely to grow back (or multiply) from the roots.
It is important to dispose of the pulled plants and not just set them back on the soil. If you pull them and set them down, even root side up, these buggers often have the ability to reroot themselves. Probably this is because they grow in cool, moist weather that can give exposed roots a fighting chance even will removed from the ground.
So, if you get out there now, before the spring growth surge, and remove your shotweed, you’ll have a better chance of reducing its numbers. Keep in mind that this plant can germinate many times in our growing seasons. It only really stops when we hit the dry heat of summer — except that the dying plants will be spitting out new seeds that will germinate when the weather turns cool and moist again. And, of course, those seeds will come to life even sooner if they land in a shady spot that your irrigation reaches.
In Seattle, you’re likely to see plants in the garden starting in January – June and again September-November. Sometimes shotweed will appear in other months as well. The plants can range from the size of a penny to the size of a geranium depending on time of year and its growing environment. And, yes, regardless of size, every plant has the potential to form flowers and seeds!
It may sound like shotweed eradication is an impossible battle to win, but because shotweed is so easy to pull, it’s one weed that doesn’t require a lot of tools. You just need a sharp eye during your daily strolls through the garden and the willingness to pull a few weeds along the way. Of course, if you’ve decided at one time or other that it looks pretty and is no big deal, like I did foolishly years ago, you may need to go after it more seriously the first (and possibly second and third) time around.
I hate this one with a passion! I am super vigilant about getting rid of it before it flowers/seeds but still it’s there again every year, seemingly in greater quantities. My mom calls it “popping weed” and it is the bane of her Eastside garden too. Ugh!
After a walk through my garden over the weekend, I was so disappointed to see shotweek popping up everywhere. I thought I had been so thorough last year removing the week before it went to seed. I wonder if there was latent seed in my soil, just waiting for the opportune moment to germinate and grow. I know I will steal 30 minutes here and there to hand weed it out before it goes to seed. As a contact lens wearer, I can attest that the seeds can go right into the eye and pop out a contact! Lens wearers, beware! Get it out of your garden now before seeds form!
PS Do you know that the Google ad running next to this post is one for herbicide?
It doesn’t surprise me that’s the case. If I use the keyword, they will come. Unfortunately, there’s only so much screening I can do. Hopefully folks will read the post and not just buy a random chemical!
Great post! I never knew what this weed was called. I have it too; frankly, it’s the least of my worries. It’s better than bindweed (morning glory)! And hey, it’s edible. I’ll give it a try in my next salad.
Thank you for this post and for the photos that helped me identify this weed. This is the first time I noticed this weed in the seedling state because it shot seeds when I tried to pull it out. Lucky for me it’s edible because I got several in my mouth! Ever since we stopped using chemicals on our lawn several years ago, we have more and more ‘herbs’ I never knew existed. I hate to think how far this one is going to spread.
This is perfect timing! I was planning on weeding today and now I know that in addition to bind weed, thistle, and chickweed, I have shotweed in my garden! Thanks, Robin!
Glad to help Willi. Bindweed and thistle — yuck. Those are tough ones to eradicate. Chickweed and Shotweed are easier to manage, but they never seem to stop coming up.
Good luck out there today!
Just a comment on the pictures. “Shotweed” refers to nearly all the bittercresses and all of these are hard to differentiate. I believe that these pictures are of Cardamine hirusta, “Hairy Bittercress”. I am not sure how to distinguish C. hirusta from C. oligosperma, but they are quite similar I believe, as are all the bittercresses. The Only way to tell C. hirusta from the others (excepting oligosperma, of which I do not know) is that C. hirusta has an unstraightened petiole.
It’s great in soup and salads, and pairs well with something bland, like potatoes. It’s a little fussy to clean in it’s small stages, and it gets a bit stringy as it sends up it’s flower stalk, though it can still be used in stock at that stage. There’s plenty of it when there’s hardly anything else fresh that’s edible in the garden, a little goes a goodly way, and it eating it seems like a perfect revenge.
Love these posts. I’m so glad I’m not alone in this weed infestation. I didn’t know what they were either. Called them Pea Shooters. Why aren’t the seeds edible? Maybe they’re they too hard to catch? 🙂
I discovered this plant in my garden about 5 or so years ago in eastern New York State. It most likely came in with some nursery plants. At first, I half-heartedly started picking it until I realized how invasive it can become. It really is all over the place, but in patches, so far. Now I am on a mission to at least minimize it in the gardens. Just finished picking enough to fill a 40# bird seed bag!! Off to the dump with it.
PS, I didn’t find the stuff to be particularly tasty.
I have engaged in a hand-weed eradication program for these little buggers for many years. I attend to my garden beds and my 200 foot long gravel driveway through March and April. In retrospect, I realize my efforts are actually a natural selection process: the larger plants no longer show up, but the nickel size ones abound, even though the small ones only produce one seed stalk. The little versions are harder to spot, escape being pulled, and therefore their genes are the ones that get passed on. Darwin and Lamarck were dead on!
Russell, same thing here! The littlest of them manage to hide and thrive in our garden too. Keep working away at them (and we’ll do the same)!
Thank you for this post. I had no idea what this little critter was called and wanted to know. Your post is perfect. I live in suburban New York, and I actually love this little plant. It’s flowering now and other than the crocus and scylla, it’s the first thing to flower. Our cool weather season is abysmally short, though, so it doesn’t seem to keep germinating much past March here, and thus doesn’t take over my garden in the way you describe. My problem weed is mugwort. Ugh!
Sherry, enjoy it. Wish I could trade some mugwort for this stuff!
I waited too long and now this weed has gone to seed all over my yard. Does anyone have advise on how to get them out without allowing the seeds to shoot everywhere?
Try to gather the tops/seeds by covering with your hand to keep them from popping. Unfortunately, once they’ve gotten to the seed spitting point, it can be tough to get them out without spreading the seeds in the process. Good luck! We’re battling it too…always…
I LOVE SHOTWEED.
It is delicious and grows in the winter. I always pick it BEFORE it flowers. I love it when I find large plants! Harvest tips: Pull it up roots and all. Remove roots before washing in a bowl or rinsing in a colander. Chop it up and use in omelets, stir fries, salads and soups. It is an excellent green. One year I did not buy any lettuce while shotweed was available. It only gets really bitter when it is old an gone to flower. I just harvest a huge pile from my community gardens greenhouse that was growing in the floor. I am eating an emmer-faro slad with shotweed, sundried tomatoes in olive oil, basalmic vinegar, garlic, pepper and salt. Topped with a bit of grated romano cheese. Excellent! EAT YOUE WEEDS.
Good for you Ruth. Keep enjoying nature’s harvest!
Ruth you are more than welcome to all the shotweed in my garden! Yesterday I spent hours weeding and have hours of weeding left. Not sure why there is such an infestation – perhaps in the soil we had delivered? There are large mats of the nasty stuff.
Debora, It could be that the soil you had delivered had seeds or it could be that seeds blew into your amended beds and took hold. In any case, get it up now or it’ll just be worse later.
Regarding weeds in topsoil and Shot weed in particular….. If your topsoil or mulch comes from a source that uses urban yard waste you’ll have LOTS of weed seed because everyone dutifully puts their weeds into the Yard Waste container and off it goes to ‘Recycling’. Composting does not get hot enough to kill seeds, end of story, so if you put Shot weed into Yard Waste as so many do, you are guaranteed to be spreading the stuff you are cursing contributing to the spread of weeds in the form of your own noxious weed seed in future compost. Cedar Grove compost is absolutely terrible in this regard and I would recommend NOT buying it for that reason. I refuse to put Shot Weed or any other seeding weed waste into Yard Waste for this very reason. Mine goes into the Garbage bin and off to a landfill, not to someone else’s garden.
Paul, Thanks for writing in. While we would agree that many finished commercial composts do harbor weed seeds or create environments where weed seeds will readily germinate, we would also point out that Cedar Grove’s most recent online quarterly quality assurance report indicates zero weed germination rates (http://cedar-grove.com/docs/Fine_quarterly-10-29-2013_New_logo.pdf). While home compost systems are rarely hot enough to cook weed seeds to a point where they are no longer viable, the systems at places like Cedar Grove essentially cook the life out of everything they compost.
Thank you everyone for clearing this up – was out weeding today and came across large patches of this with my son (in Seattle). We could not figure out what it was. Jumping bugs?? Googling led me to this site…we have our work cut out for us – it’s everywhere.
Beth, glad we could help…at least help you figure out what it is…pulling and eradicating it is up to you & your son. Fortunately, this isn’t the hardest weed to pull.
Shotweed is also an excellent forage for chickens. It’s one of the first greens available for them in the winter, and chickens will devour both the plants and the seeds.
i use a little sprinkle of baking soda on each
“spotweed” & it kills them dead.
Our soil is low in pH so the b.soda raises that.
Spotweed seems to detest “sweet” soil –
glad i tried this little experiment cuz got tired of getting hit hard on the skin & eyes.
Sharon, thanks for sharing your tips for “spotweed”…never heard shotweed called spotweed before, so thanks for sharing that info too.
I serve deviled eggs with a wee sprig o’ shotweed stuck into the top–lovely! I also love it in a quick sandwich when I’m out of lettuce. It’s not a big deal to try it: next time one crosses your path, nip it in the bud and pop it into your mouth. It tastes like watercress. Cheaper–and usually always available.
thanks for sharing your shotweed eating tips!
What would happen if you set fire to a patch of shot weed? Would it kill it?
Flame weeding shot weed has worked for us, but we only apply fire in situations were starting an uncontrolled burn isn’t going to happen. Attempt with extreme caution!
I am wondering what type of soil shotweed thrives in–it seems to prefer a sandy/loamy soil. Am thinking it dislikes soil rich in organic matter…so adding mulch might deter future growth?
Unfortunately shotweed thrives in just about any soil. It loves to pop up in mulches and rich soils too. It loves moisture, which mulches tend to hold. Fortunately, it’s a relatively easy week to pull!
Good post! We are linking to this particularly great article
on our website. Keep up the great writing.
I have a “zero tolerance” program on this weed here in NJ and decided I needed the find out the name. Thx great article.
I was over a friend’s house this weekend in PA and he is not a gardener at all (doesn’t even own a shove!). Well in the back of his lawn – where I assume the weed started it’s invasion, he had 10s of thousands, all standing about a foot tall and rip with 100s of hundreds of thousands of seeds ripening an readying their ongoing invasion. It was a bit horrifying.
This weed must be a foreign invader. It appears to have a bigger cousin too (taller up to 2.5 ft and large hairy, rich green leaves) which is easier to pick because it is tall and has a easy tap root to yank from the top of the stalk. I had many hundreds when I moved in to this house about 2.5 years back – now I am down to a few dozen sprouts here and there. I took my eradication of this bigger weed into the surrounding wood lots to help keep it at bay.
I somehow doubt either of these weeds are native because both are only recent additions to roadsides and footpaths – not to mention lawns and gardens.
BTW One strategy i use with all weeds, I do a slow surround – cleaning out thinly invaded areas first and moving towards the epicentre. Seed remove naturally is key because as with all weeds – it is a multi-year affair to at least get control.
Good luck with this baby because once you realized you have been invaded – it is a moment of “WTF!”
I love Shotweed. It is a wonderful free source of iron & vitamins. It has 10 times more iron than spinach. So do dandelions. Both of these should not be seen as pests. They are free wonderful nutrition. The Shotweed is in the cress family & tastes just like watercress. Coming from Europe, we used to make cream cheese & cress sandwiches. The cress adds a “bite” to the mild cream cheese. Now I make cream cheese & Shotweed sandwiches. I eat the flowers & little feathery side branches that I pull off the main stem. I also put lots of it in a green leafy salad. It just blends right in & adds a little look of variety among the lettuce leaves. Awesome stuff. I look forward to seeing it again every year!
we love it too Virginia!
1st time it is under my 33 yards of large nugget bark.
I have pulled it all out – dead tired.
What can I use to prevent the return. What product and how to use it. Do I have to remove the bark or can I put something over the bark and WATER it down to ground? HELP.
Linda, you probably will have more. Shotweed shoots seeds and lays down a thick, rich bank (account) of seeds for future generations. You could try smothering it with more wood chip mulch. And, don’t disturb the mulch, or you’ll expose the seeds to light, and they’ll germinate more readily. Or, perhaps, consider it a food crop & start harvesting to eat or to feed to chickens. They love it! Good luck 🙂
Vinegar appears to be effective against this horrible weed. (I’ve been fighting it for years). But I’ve learned that vinegar does not kill the roots. Do you know if the loss of the leaves is enough to kill the roots? I usually just spray large areas of the weed, not individuals.
John, depending on the concentration of vinegar, it might kill the whole plant. And, it might also depend on the age. Given these are annual weeds, I’d be surprised if the original plant actually comes back if you thoroughly kill the top growth. It is likely you have a seed bank going, so when you kill one round of plants, it exposes seeds below to sunlight and gives them space to then pop right up in place of what you just killed. Good luck!
This was very interesting and helpful to me;as today I am planning to get out there and pull some of these monsters that have taken over my front yard..They are growing up so fast in the gravel I have in front of my deck..Thanks for all the information …I always wondered what it was called ..Shotweed now I know …
Managing Weeds in Seattle — Shotweed