Cecelia Alexander, no rights reserved (CC0) · iNaturalist
Noccaea spp.
pennycress
Temperate and montane Northern Hemisphere
Overview
Noccaea is a genus of roughly 80 small annual to perennial herbs in the cabbage family (Brassicaceae), found across temperate and mountain regions of Eurasia and North America, many segregated from the older genus Thlaspi. Plants form a basal rosette of smooth, often blue-green leaves and send up slender stems 5-40 cm (2-16 in) tall clasped by arrow-shaped stem leaves. Short racemes of small four-petalled flowers, usually white and sometimes flushed pink or lilac, open from spring into summer and are followed by flattened, winged, heart- to disc-shaped seed pods typical of the family. Several species grow on metal-rich and limestone soils, and N. caerulescens, alpine pennycress, is studied as a hyperaccumulator that draws high levels of zinc and cadmium into its tissues, a trait used in research on cleaning contaminated land. Most species occupy rocky slopes, screes, grassland, and alpine turf, often on calcareous ground. Plants are generally low and short-lived, with annual species completing their cycle in a single season.
Native Range
Noccaea is native across the temperate and montane Northern Hemisphere, through Europe, the Mediterranean, temperate Asia, and parts of North America. Species favour rocky slopes, screes, alpine meadows, and grassland, frequently on limestone or metal-rich soils. Several have narrow ranges tied to particular mountain systems or soil types.Suggested Uses
Grown in rock gardens, alpine troughs, scree beds, and gravel plantings, spaced 10-20 cm (4-8 in) apart. The early white flowers suit naturalistic alpine and wildflower settings, and several species are grown for research into metal-rich soils rather than ornament.How to Identify
Appearance
Size & Dimensions
Height2" - 1'4"
Width/Spread4" - 8"
Bloom Information
Flowering runs from spring into early summer, mainly April to June, with alpine species opening later as snow clears. The small white flowers are held in short clusters that lengthen as the flattened seed pods develop. Annual species flower and set seed quickly within a single season.
Detailed Descriptions
Flower Description
White, sometimes pink-tingedFoliage Description
Blue-greenGrowing Conditions
Sun Requirements
Requires 6-10 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