Cardamine impatiens (Narrow-leaf Bittercress)
| Also known as: | Bushy Rockcress |
|---|---|
| Genus: | Cardamine |
| Family: | Brassicaceae (Mustard) |
| Life cycle: | annual, biennial |
| Origin: | Europe |
| Status: |
|
| Habitat: | part shade, shade; moist woods, thickets, stream banks |
| Bloom season: | May - July |
| Plant height: | 6 to 30 inches |
| Wetland Indicator Status: | GP: none MW: FAC NCNE: FAC |
| MN county distribution (click map to enlarge): |  |
| National distribution (click map to enlarge): |  |
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Detailed Information
Flower: 
![[photo of flowers]](/udata/r9ndp23q/white/narrow-leaf-bittercress_0523_162815.jpg)
Elongating clusters of stalked flowers at the top of the plant and at the tips of branching stems, with open flowers in small clusters at the tip and fruit forming below. Individual flowers are white to greenish, tiny with 4 petals but these are often absent or indistinct.
Leaves and stem:
![[photo of stem leaves]](/udata/r9ndp23q/white/narrow-leaf-bittercress_0523_162657.jpg)
There are both basal and alternate stem leaves. Stem leaves are compound with 13 to 25 leaflets, to ~6 inches long. Leaflets are generally lance to narrowly egg-shaped with an asymmetrical base and have a minute stalk; the edges may be smooth, jagged or sharply toothed. The terminal leaflet is largest, 3/8 to 1½+ inches (1 to 4+ cm) long
![[photo of leaf auricles]](/udata/r9ndp23q/white/narrow-leaf-bittercress_0523_162442.jpg)
At the of the compound leaf stalk is a pair of narrow, pointed lobes (auricles).
![[photo of basal leaves]](/udata/r9ndp23q/white/narrow-leaf-bittercress_0501_154759.jpg)
Basal leaves are compound with 3 to 11 leaflets that have asymmetric bases and rounded lobes that may be further notched or lobed. Leaves and stems are hairless. The basal rosette is produced the first year and flowering stems are usually produced the second year.
Fruit:
![[photo of fruit]](/udata/r9ndp23q/white/narrow-leaf-bittercress_0527_154113.jpg)
Fruit is a straight slender pod, mostly ascending, up to about 1 inch (1.6 to 3+ cm) long. Ripened pods burst open and can shoot seed several feet from the mother plant, thus it can form dense colonies fairly quickly.
Notes:
Narrow-leaf Bittercress is a relatively new exotic species in Minnesota, and quite invasive. According to the MN Dept. of Agriculture, a single plant was discovered at Riverside Park in 2008; by 2009 they were pulling out truckloads of it. It has been found along waterways and especially along trails, very likely via hikers, bikers and dog walkers spreading weed seed when travelling from infested to uninfested areas without cleaning their bike tires, footwear, or animal's feet and coat. This is a continuing problem in the battle against invasive species—always clean your gear!
Narrow-leaf Bittercress is a Prohibited Control species and needs to be stopped before it becomes more unmanageable. The root system is shallow and it hand pulls easily, but herbicide is recommended for larger infestations. See the MN Dept. of Agriculture's fact sheet for more information on control measures.
It resembles some other Cardamine species, most notably Pennsylvania Bittercress (Cardamine pensylvanica), but the latter has larger and better defined flowers, lacks the auricles on stem leaf stalks, leaflets often (not always) have no stalk, and stems are usually at least sparsely hairy, especially near the base. Note that I did see reports of C. impatiens on both iNaturalist and EDDMapS that are incorrectly IDed and are actually C. pensylvanica, so the real distribution and abundance of this weed are not known, but that's true for virtually all weeds.
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More photos
Narrow-leaf Bittercress plants
basal rosettePhotos by K. Chayka taken at Battle Creek Park, Ramsey County, and Fort Snelling State Park, Hennepin County.
Comments
Have you seen this plant in Minnesota, or have any other comments about it?
on: 2010-06-12 20:39:09
some removal activity in May, but much remains
on: 2010-09-29 16:21:55
Lake Rose Park, Minnetonka
on: 2011-12-01 11:29:28
I saw lots of bittercress at Fort Snelling State Park early this summer. It was common on the SW end of Pike Island, but also along the hiking/biking trail that goes over to Minnehaha falls. Heading towards the state park once you passed under the highway 5 bridge the plant was all along the trail. At Minnesota Valley NWR at the Bass Ponds, specifically the stormwater pond next to Hwy 77 there is a large patch in the woods just north of the pond. Another patch is in the woods by the Bloomington visitor center.
on: 2015-08-18 15:24:08
This pesky little plant grew in profusion in a part of our lot where we replaced buckthorn with native prairie plantings. They are easily pulled, but have an impressive seed bank and so keep showing up again. There is also bittercress in the woods behind the restroom on the west side of Normandale Lake, near the parking lot.
on: 2016-05-17 16:24:59
Pulled my first Narrow Leaf Bittercress this afternoon. We have lived here 25 years and I did not knowingly see it before. Received an alert from the Wisconsin DNR and recognized it from a photo I took last week (because it was new to me). Only about a dozen plants. Hope it is the ONLY population but will keep watching!
on: 2016-05-20 12:08:13
Noticed a few plants last year but didn't know what it was. Have over 1,000 this year so I spent the time to determine what it was. Ugh. Will begin pulling.
on: 2017-04-29 17:09:42
Just noticed it this year and it seems to be spreading in a wet part of our yard where a dry creek flows.
on: 2017-05-03 21:48:45
We saw this today in large numbers along the edge of the backwaters and seeps at the base of the bluff just below the Mississippi River National Wildlife Refuge visitor center in Bloomington.
on: 2017-05-19 17:14:24
I just pulled what I believe is cardamine impatiens out of the edge of my lawn today. I live in the woods, Shakopee, MN.
on: 2017-06-27 12:31:46
If anyone finds this in Wisconsin, please contact us at invasive.species@wi.gov and send photos and the location. We only know of a few sites in WI so far and want to keep it that way. It is regulated as a prohibited invasive in WI. Thanks!
on: 2020-06-05 11:56:41
I believe this is growing at the base of the buckthorn on my neighbor's property and started invading our adjacent gardens--Pheasant Ridge Road, Medina MN 55391.
on: 2022-05-17 12:21:29
Numerous narrow-leaf bittercress plants in the forest, visible near trails, among bedstraw plants. This is at least partially state-owned and managed.
on: 2022-06-26 14:00:50
Found it in my backyard. My neighbor recognized it and advised me to pull it, immediately
on: 2022-06-27 14:52:34
Found it in my backyard. My neighbor recognized it and advised me to pull it, immediately
on: 2023-04-29 21:08:49
Fairly abundant in seeps below the goat prairie. Cohabiting with skunk cabbage (lovely) and way too much garlic mustard (evil).
on: 2023-05-24 20:22:55
We are constantly fighting weeds in our yard that come from the ditch that is uncontrolled by MnDot along Hwy 51 (Snelling). Buckthorn, garlic mustard, now this.
on: 2023-06-04 20:55:56
Several plants spotted.
on: 2023-06-28 18:12:08
I just found roughly a few hundred plants on a shady hillside in the woods behind my house. They've mostly released their seeds already, so there's gonna be a whole lot more. I'll pull the plants that are there currently, and continue pulling young ones as they come up to prevent them from setting seed. I'm hoping that it'll be outcompeted eventually, as the surrounding vegetation is extremely dense and made up of a diverse mix of aggressive native species that should be able to compete against it with continuous pulling.