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little western bittercress

Cardamine oligosperma · Brassicaceae

little western bittercress (Cardamine oligosperma)
Photo: (c) Alex Abair, some rights reserved (CC BY) · CC BY · via iNaturalist

little western bittercress (Cardamine oligosperma) is a perennial herbaceous plant in the Brassicaceae family. It is native to North America. USDA records it as hardy in zone 4 and warmer, down to about -23°F.

At a glance

Typeforb-herb USDA
Lifecycleperennial USDA
Native statusnative USDA
Mature height1.7 ft USDA
Lightshade USDA
Water needmedium USDA
Growth raterapid USDA
Soil pH5.5–7 USDA
BloomMarch–April USDA
Flower colorWhite USDA
Hardiness zones4 and warmer USDA
Guild layerherb-layer Derived
Nursery availabilityNo Known Source USDA

USDA quoted from the USDA PLANTS database · Derived computed by a fixed rule from those columns. No value on this page is estimated.

Growing conditions

It tolerates full shade. USDA rates it as having moderate water needs. Its drought tolerance is rated low. It will not tolerate waterlogged soil — USDA rates its anaerobic tolerance as none. It is recorded on soils from pH 5.5 to 7 — a broad range that spans acidic through mildly alkaline ground. Its cold limit is zone 4.

Size and growth

At maturity it reaches about 1.7 ft, making it about knee height. It grows quickly.

Bloom period

USDA records a bloom period of March through April. Flowers are white.

A flowering date, not a pollinator rating.

Foliage, flower and season

Summer foliage is green, fine in texture. Its flowers are not conspicuous — a plant for form and foliage. Its active growth period is spring. USDA rates its lifespan as short, so plan on replacing or resowing it rather than treating it as permanent structure.

What the site needs to provide

USDA records it across sites receiving 14 to 50 inches of annual precipitation. The low end of that band is genuinely arid, so it has a wide tolerance for dry country. It needs at least 60 frost-free days to finish its season. It roots to at least 6 inches. Fertility requirement: high.

Propagating it

Seed is the only propagation method USDA lists. Division and cuttings are not listed as options. USDA records no cold-stratification requirement, so seed should germinate without a chilling period. Its seed spreads at a moderate rate. It does not spread vegetatively, so it will stay where you put it.

Resilience and wildlife

Browsing animals rate it barely palatable — the sourced basis for calling it deer-resistant. Its fire tolerance is rated none. Its growth form is recorded as single crown.

Role in a guild

Herb layer. In a layered planting this is the herbaceous middle — perennials and grasses that fill the space between ground cover and shrubs. The layer is derived by a fixed rule from growth habit and mature height.

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Tags

deciduousdeer-resistantnativeshade-tolerantfast-growing

Related plants

Others in Cardamine

Similar role and hardiness

Where this data comes from

Every value on this page comes from the USDA PLANTS database record for symbol CAOL, or is computed from those values by a fixed rule. Nothing here is estimated or model-generated. Where USDA publishes no value, this page omits the claim rather than filling the gap.

Read our full data sources and methodology.

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