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)
Flowers are in rounded clusters averaging ½ inch across at the top of the plant and at the end of branching stems. Individual flowers are white to greenish, tiny with 4 petals but these are typically 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 in groups of 13 or more, to 6 inches long. Leaflets are generally lance to arrowhead-shaped, about 1 inch long with asymetrical bases; the edges may be smooth, jagged or sharply toothed.
![[photo of leaf auricle]](/udata/r9ndp23q/white/narrow-leaf-bittercress_0523_162442.jpg)
Where the leaf joins the stem are a pair of narrow, pointed lobes (auricles). When the leaf is detached from the stem the auricles remain.
![[photo of basal leaves]](/udata/r9ndp23q/white/narrow-leaf-bittercress_0501_154759.jpg)
Basal leaves are compound in groups of 3 to 11, with rounded lobes that may be further notched or lobed, and asymetrical bases. Leaves and stems are hairless. 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, erect to spreading, up to about 1 inch long. Ripened pods burst open and can shoot seed several feet from the mother plant, thus it can form dense colonies fairly quickly and crowd out native plants.
Notes:
Narrow-leaf Bittercress may resemble some other Cardamine species, most notably Pennsylvania Bittercress, but the latter has larger and better defined flowers while the former has the distinct auricles at the leaf base. This is a new exotic species in Minnesota, and highly 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. So far it has been found mostly in the Mississippi River Valley, and probably spreads via the river. At Battle Creek Park in St. Paul, it has been found along the dirt bike trails throughout wooded areas. It is very likely that weed seed is transported by bikers and dog walkers when they travel 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 targeted Early Detection 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. If you have spotted this plant anywhere in MN, please post a comment below so new infestations can be dealt with as quickly as possible.
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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 at 7802 Horizon Drive, Shakopee, MN 55379.
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