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Cardamine bulbosa

bulbous cress

Brassicaceae eastern North America

Attracts Pollinators Attracts Butterflies

Native to North America

SunPart Shade – Full Shade

WaterHigh

HardinessZones 3–8

Overview

Cardamine bulbosa is a herbaceous perennial in the mustard family (Brassicaceae), growing from a small rounded tuber to 6–20 inches (15–50 cm) tall. It forms a rosette of long-stalked, rounded to heart-shaped basal leaves, while the upright flowering stem carries smaller, oblong, shallowly toothed leaves. In spring the stem ends in a compact raceme of white flowers, each with four petals and measuring about 0.4–0.6 inch (10–15 mm) across. Slender erect seedpods 0.8–1.2 inches (20–30 mm) long follow, splitting to release small seeds. The plant grows in consistently moist to wet ground — wet woodlands, spring seeps, streambanks, wet meadows, and calcareous fens — across eastern North America. Foliage emerges early and flowers before the tree canopy closes, then the plant often goes dormant by midsummer as soils dry, leaving a gap in the planting later in the season. The tuber, leaves, and stems have a peppery, cress-like flavor and have been eaten raw. It spreads slowly by seed and by offsets from the tuber, forming loose colonies in suitable wet habitat.

Native Range

Cardamine bulbosa is native to eastern North America, ranging from southern Quebec and Ontario south to Florida and Texas and west to the Great Plains. It is most frequent in moist, base-rich soils of the eastern deciduous forest region.

Suggested Uses

Cardamine bulbosa is used in woodland gardens, rain gardens, and the moist margins of ponds and streams as a spring-flowering native. It supplies early nectar and pollen and serves as a larval host for the falcate orangetip butterfly. It naturalizes into loose colonies where soils remain reliably moist.

How to Identify

Look for a low rosette of rounded, long-petioled basal leaves and an erect stem 6–20 inches (15–50 cm) tall bearing smaller oblong leaves. The terminal cluster of four-petaled white flowers, each 0.4–0.6 inch (10–15 mm) across, appears in spring above the foliage. The thickened underground tuber and the peppery taste of the crushed foliage separate it from the smaller-flowered, fibrous-rooted bittercresses such as C. pensylvanica.

Appearance

Size & Dimensions

Height6" - 1'8"

Width/Spread6" - 1'

Colors

Flower Colors

white

Foliage Colors

green

Fall Foliage Colors

no change

Bloom Information

Bloom Period

~5 weeks

Spring

Flowers open from April through June, earliest in southern populations and in warm springs. Bloom on a colony lasts about 4–5 weeks, with white racemes carried just above the basal leaves. Pollination is by early-season bees and flies, after which the upright pods mature and the plant begins to die back.

Detailed Descriptions

Foliage Description

green

Growing Conditions

Sun Requirements

SunPartial Shade SunFull Shade

Requires 2-6 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 7.0(Neutral)

357912

Soil Types

loam silt clay

Drainagewet

Water & Climate

Water Needs

High

Frost Tolerance

hardy

Time to Maturity

2-3 years from seed to flowering

Care & Maintenance

Care Guide

Cardamine bulbosa grows in part shade to full shade in soils that stay moist to wet through spring, including heavy loam, silt, and seasonally flooded ground. It tolerates standing water in early spring but needs steady moisture rather than drought. In cultivation it suits the edges of ponds, rain gardens, and woodland seeps where the soil does not bake dry. Because it goes summer-dormant, it is combined with later-emerging perennials that fill the space it vacates. It needs no fertilizer in fertile woodland soil and self-sows where conditions stay damp.

Pruning

No pruning is required. Spent flowering stems can be left to ripen and drop seed or removed once pods brown if self-seeding is not wanted. Foliage yellows and disappears on its own as the plant enters summer dormancy.