Winter Weeds: Common Milkweed In late fall when I’m hiking near fields and roads I often see plants with big seed pods and white fluff tumbling out. The plants are milkweed but they look quite Official Blog of the UC Master Gardener Program of Contra Costa County Hairy bittercress is an annual weed that can spread quickly.
Winter Weeds: Common Milkweed
In late fall when I’m hiking near fields and roads I often see plants with big seed pods and white fluff tumbling out. The plants are milkweed but they look quite different from their summer appearance.
Common milkweed is a conspicuous perennial in winter because its large, warty, seed pods stand high on three to five foot stems.
The pods are fat at the bottom, pointed at the top and split open on their long edge to reveal soft, silky fluff carefully layered inside. Each wad of silk is attached to a flat, brown seed.
When exposed to the weather the silk becomes fluffy and eventually flies off the plant, carrying its seed cargo as far as it will go. The pods stand high to send their bounty on the wind.
To me one of the great mysteries of milkweed is that it looks so different in winter. In summer it’s weighed down with large, drooping, pink flower umbels but now the pods stick up alone and there are far fewer of them than the number of flowers in the umbel. I have read that only one flower in each milkweed umbel produces a seed pod. (Do any of you know how this works?)
Common milkweed is a great plant for attracting monarch butterflies to your garden. If you already have milkweed you can leave the stems standing over the winter and watch where the seeds fly.
When you’re ready to clear them away in the spring, Marcy Cunkelman suggests you save the dried stems and put them out in mid-April for the birds to use as nesting material. The fibers are strong and peel off in strips. They’re quite a favorite of Baltimore orioles.
(photo by Marcy Cunkelman)
3 thoughts on “ Winter Weeds: Common Milkweed ”
I like milkweed, enjoyed looking for the plant. When I was in 3rd(Now here goes telling people “I am old”) our school was brought truckloads of burlap sacks to fill with milkweed pods because they were used to fill the vests the WW II GIs wore. We were all so proud doing it. This was when I lived in Gibsonia & one of the buildings you now see in a St. Barnabas Senior Community in Richland Twp. is actually our old grade school (talk about recycling!!). We had a chart in each classroom & I don’t know what the winner got, I suppose a party or something. So I always have fond memories about the milk weed. However, I did not know that the seeds were not in every pod. Some of these weeds are what keep winter in the woods interesting it seems. Everything for a purpose if only to enjoy.
I will look for pods in my fields to save for nesting material in April. Always enjoy your posts — the dried milkweed photo is great — barbara
I love milkweed too!
It smells great when the blossoms bloom. Also, when in bloom they attract a great variety of insects, bees, butterflies and the like. Monarchs and other insects make it their home for the summer season. Also, note, raising Monarch butterflies is great fun for kids and us adults too. And then, like Kate describes, gathering the silky pods in late fall for the birds in the spring for nesting material is an added bonus. So much to enjoy from a simple weed and it cost only some time.
That is the best thing about nature. It cost so little to enjoy so much. Everyday a great film is being played right outside your door. Every season brings a newly released feature film. Make some popcorn if you like and enjoy. Enjoy my friends, enjoy!
Seed Pod Weed
Hairy Bittercress (Cardamine hirsuta)
I’ve become fascinated with this weed, at least so far. I’ve more-or-less got it under control in my garden. I really don’t remember it from years ago, but it sure has been a pest the last 5 years or so. Not a native of California, it is now here for the foreseeable future… and beyond. I can’t say it’s the worst weed in the garden, but it sure requires attention to keep it under control. Especially these days when it will be competing for available water.
Even if you didn’t recognize it outright, maybe you’ve had the experience of being out in the garden pulling winter weeds when you’re pulling what looks like a small “innocent” weed only to find it exploding seeds in your face and all over the nearby garden? The most likely culprit is Hairy Bittercress (Cardamine hirsuta), which starts growing almost immediately with the onset of the late winter rains. It originally looks like a small, flat rosette of small leaves and then in what seems like the next day, quickly produces small white, four-petal flowers on wiry green stems. Most of the problems with this weed can be “solved” if you pull it at this stage or at least before it flowers. Seemingly overnight, the flowers form needle-thin seed pods, which explode at the slightest touch, sending seeds in all directions (averaging around 600 seeds per plant… and the bigger the plant, even more seeds). Besides your garden, the seeds are easily propagated in cracks in flagstone, brick or concrete walkways.
Because Hairy Bittercress thrives in moist conditions and disturbed soil, it is also a pest in nurseries, and can be brought home via plant purchases. If you think that’s a problem for you, some cautious gardeners carefully remove the top inch or two of soil in the pots before planting. (If you do this, you should dispose of the scraped-off soil in your green can.)
If all else fails, Hairy Bittercress is a member of the mustard family and is edible, but you need to do your own research to find the right recipe to enjoy it (for an example, see http://www.eatingniagara.com/2013/04/weed-wednesday-make-that-hairy.html). To get ahead of its persistence in the garden, it’s definitely worth patrolling your garden for this weed once or twice a week during the winter and spring. It’s easy to hand pull when young. Once the seeds pop, you’ll be fighting a much bigger crop next year and it’s rare that herbicides would be considered appropriate for control in a home garden.
Another reason it’s my “favorite” weed? I still remember a fellow student in our Master Gardener class relating how she had “convinced” her young son to help weed the spring garden and he was complaining about the weed seeds popping in his face. She answered him by telling him to go in the house and get his safety goggles on and keep on weeding… something you might be considering adding to your gardening tools if you let Hairy Bittercress (Cardamine hirsuta) go to flower and reseed.
Hairy bittercress: A weed to watch out for
Hairy bittercress is an annual weed that can spread quickly.
Flowers and seed pods of hairy bittercress. Photo by Lori Imboden, MSU Extension.
Have you recently noticed plants with small, white flowers on the edges of your lawn, flowerbeds and rock pathways? During April and May, populations of the winter annual weed hairy bittercress (Cardamine hirsuta) become increasingly visible. Hairy bittercress has a low growing rosette similar in form to a dandelion. It raises its profile in early spring with the appearance of flowers and seeds on a vertical stem. Like many members of the mustard family, hairy bittercress sets seed prolifically. It grows quickly and a few plants or seeds can generate a more widespread infestation in even a year’s time.
The first true leaves of hairy bittercress are heart shaped. Photo by Erin Hill, MSU.
Hairy bittercress is a winter annual weed. Its seeds germinate in fall beginning as early as September. The first true leaves are heart-shaped, followed by compound leaves with two or more pairs of leaflets and a kidney shaped terminal leaflet. The leaves that emerge in the fall form a small rosette that will overwinter. Once the weather warms in spring, it sends up stalks of small, white flowers followed by slender seed pods known as siliques.
Hairy bittercress leaves have two or more pairs of leaflets and a kidney shaped terminal leaflet. Photo by Lori Imboden, MSU Extension.
Once the seed pods ripen, disturbing the pods can propel the seeds as far as 16 feet from the mother plant. This seed dispersal adds to the soil seed bank and primes the area for another infestation to emerge in early fall. After setting seed, the life cycle is complete and the plants die. Hairy bittercress and other winter annual weed species, like common chickweed and purple deadnettle, are not typically present during the summer months.
Once the seed pods ripen, disturbing the pods will send the seeds flying as far as 16 feet. Photo by Lori Imboden, MSU Extension.
Hairy bittercress is best managed mechanically when it is young. Remove it by hand, hoe or tillage in early fall or early spring before it sets seed. If plants are flowering, composting is discouraged as seeds may develop. To manage this weed using herbicides, the proactive approach would be to use a pre-emergence herbicide in the late summer (late August to early September) to target the plants at the time of germination and prevent successful emergence.
If plants have already emerged, applying a post-emergence herbicide to actively growing plants before seedpods form may be effective. If using an herbicide, be certain it contains an active ingredient that will target this weed. Always read and follow all labeled instructions to increase effectiveness and prevent personal or environmental harm.