White mountain marsh-marigold - Caltha biflora





"Caltha leptosepala howellii is a PERENNIAL growing to 0.3 m (1ft) by 0.3 m (1ft in). It is hardy to zone (UK) 3. It is in flower from May to June. The flowers are hermaphrodite (have both male and female organs) and are pollinated by Bees, beetles, flies.
Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and can grow in heavy clay soil. Suitable pH: acid and neutral soils. It can grow in semi-shade (light woodland) or no shade. It prefers wet soil and can grow in water." [PFAF]


Two varieties occur in BC:
1. Leaves longer than wide, the margins more sharp-toothed than round-toothed; flowers usually 1 per stem; subalpine and alpine......................... var. leptosepala
1. Leaves nearly as wide as long, the margins subentire to broadly round-toothed; flowers mostly 2 per stem; lowland to subalpine........................... var. biflora (DC.) Lawson [IFBC-E-flora]


Edible Uses



"A plant of boggy soils and shallow pond margins[1], it requires a deep rich slightly acidic soil[200]. It grows well in heavy clay soils. Plants are hardy to about -20°c[187]. A greedy plant, inhibiting the growth of nearby plants, especially legumes[54]. There is some disagreement over the correct name for this species, with some authorities calling it C. howellii." [PFAF]


"Seed - best sown as soon as it is ripe in a cold frame in late summer[200]. Stand the pots in 2 - 3cm of water to keep the soil wet. The seed usually germinates in 1 - 3 months at 15°c[138]. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in a tray of water in a cold frame until they are at least 15cm tall. Plant them out into their permanent positions in the summer. Division in early spring or autumn[200]. Very easy, larger clumps can be replanted direct into their permanent positions, though it is best to pot up smaller clumps and grow them on in a cold frame until they are rooting well. Plant them out in the summer or following spring." [PFAF]


Page last modified on Saturday, July 15, 2017 1:22 PM