Narrowleaf bittercress is a small Eurasian mustard-family plant that has become an invasive weed in parts of the northeastern U.S., where its ripe seed pods snap open and fling seeds in a shower. Look for the tiny ear-shaped lobes that clasp the stem at the base of each stem leaf.
Appearance
- Growth form
- An annual or herb, about 4 in–3 ft (10–90 cm) tall. Biennial plants make a leafy rosette the first year and flowering stems the next.
- Leaves
- Compound leaves with 5–17 toothed or lobed leaflets; lower leaves are larger. Small pointed ear-like lobes () clasp the stem at each stem-leaf base.
- Flowers
- Tiny white to greenish flowers in small rounded clusters at the stem tips. The four petals are often tiny or missing.
- Flowering time
- May to July in Wisconsin.
- Fruit
- A narrow, flat, hairless pod 0.4–1.4 in (10–35 mm) long.
Look-alikes
Pennsylvania bittercressCardamine pensylvanica
Pennsylvania bittercress has no auricles where the leaf meets the stem, and its flowers have four clear white petals in longer clusters. It blooms earlier, April to June.
Why they get mixed upBoth have divided basal leaves with rounded leaflets and narrower leaflets on the stem leaves.
| Flowers | Auricles at leaf base | Bloom time | |
|---|---|---|---|
| Narrowleaf bittercress | Tiny, petals missing or indistinct, rounded clusters | Yes, a pair clasping the stem | May–July |
| Pennsylvania bittercress | 1/8–1/4 in, 4 white petals, long clusters | No | April–June |
| Small-flowered bittercress | 1/8 in, 4 white petals, long clusters | No | April–June |
| Cuckooflower | 1/2 in, 4 white petals, loose clusters | No | May–June |
Where it lives
- Typical habitats
- Disturbed woods
- Forest edges
- Roadsides
- Lawns and gardens
- Range
- Native to temperate Eurasia, including Japan and Korea. Introduced to North America; in New England it grows in Connecticut, Maine, Massachusetts, New Hampshire, and Vermont, and it is also found in Wisconsin.
- Preferred conditions
- Shady, somewhat moist ground, often in forests disturbed by people. It grows in both wetland and upland spots.
- Flowering
Flowers May–Jul
Flowers May–Jul
Life cycle
- Seed dispersal
- Dry pods split suddenly and throw out their seeds in a shower, which helps it spread quickly.
Conservation
- IUCN Red List
- NENot EvaluatedNot yet assessed
- Status
- It is listed as invasive in Connecticut, Maine, and Massachusetts, and is prohibited in Connecticut and Massachusetts.
More species to explore
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