American yellowrocket is a native wild mustard of northern North America, found across much of Canada and the western U.S. as well as parts of Asia. It has bright yellow four-petaled flowers and slender seed pods that point straight up along the stem.
Appearance
- Appearance
- A biennial or short-lived perennial with stiff, branching stems usually 4–24 in (10–60 cm) tall, sometimes up to about 3 ft (1 m).
- Leaves
- Lower leaves are divided, with a large rounded end lobe. Stem leaves have earlike lobes at the base; on the upper leaves these lobes are fringed with tiny hairs.
- Flowers
- Bright yellow four-petaled flowers in clusters at the branch tips. Petals are mostly 3/16–1/4 in (5–6 mm) long.
- Flowering time
- May to June
- Fruit
- Narrow, straight pods 1–1¾ in (25–45 mm) long that split open when ripe. The leftover at the pod tip is short, under 1/16 in (0.5–1.6 mm).
Look-alikes
Garden yellowrocketBarbarea vulgaris
Garden yellowrocket has slightly bigger petals (1/4–5/16 in, 6–8 mm) and a longer beak at the pod tip (2–3 mm). Its pods are shorter and angle outward instead of hugging the stem, and the earlike lobes on its upper leaves have no fringe of hairs.
Why they get mixed upThis weedy European relative is far more common and looks very similar.
Where it lives
- Typical habitats
- Stream banks
- Wet meadows
- Lake and river shores
- Subalpine slopes
- Range
- Native from Alaska and across much of Canada to the western U.S., with scattered populations in the northern Great Lakes states. In New England it is known only from Maine and New Hampshire, where it is extremely rare.
- Preferred conditions
- Wet places: meadows, riverbanks, rocky shores, and wet rocky slopes in the mountains. It is treated as a wetland plant.
- Flowering
Flowers May–Jun
Flowers May–Jun
Conservation
- IUCN Red List
- NENot EvaluatedNot yet assessed
- Status
- Listed as endangered in New Hampshire, where it has not been seen recently. In Maine it has not been seen in a long time and may be gone.
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