Description of Caltha palustris var. alba (White Marsh Marigold)

Caltha palustris var. alba is the white form of marsh marigold. You may see it sold as Caltha palustris 'Alba'. It is a small plant that flowers early, so it earns its keep when most pond-edge plants are still slow.

Appearance

Caltha palustris var. alba makes a low mound of rounded, glossy leaves. New growth looks fresh and bright in late winter. Flowers open on short stems above the foliage. The blooms are simple and open, with clean white petals and a yellow centre. In the UK you can see flowers from March into April, and it can carry on longer in a cool spring. Mature height is usually 20 to 30cm, with a similar spread. After flowering, the leaves bulk up and form a tidy patch of green that fills a gap at the pond edge.

It pairs well with forget-me-nots, Japanese primroses, and low ferns. It also looks good at the front of taller marginals because it does not hide other plants.

Care Guide

Grow Caltha palustris var. alba in rich soil that stays wet. It thrives where water drains slowly or where the soil is kept damp by a pond liner. Sun gives the best flowering, but light shade is fine, especially near shrubs or a hedge. The main job is keeping the roots wet through spring and early summer.

• Planting spot: Bog garden, pond margin, or a container sat in a shallow tray of water.
• Water: Do not let it dry out. In a raised bog, water little and often in warm spells.
• Feeding: A mulch of compost in late winter supports strong growth. You can add a small handful of slow-release feed in spring if the soil is poor.
• After flowering: Remove tired stems if you want a tidier look. Leave foliage to feed the plant.
• Division: Lift and split every few years in early autumn or early spring if the clump gets crowded.

Suitability for Bog Garden

Caltha palustris var. alba is made for bog gardens. It likes wet feet and it copes with cool, heavy soil. It also suits wildlife ponds because it provides early cover and early nectar when insects first start moving. Plant it where you can see it from the house, as it is one of the first pond-edge plants to look alive each year. Keep it out of the driest rim of a bog planter, and it will repay you for years.

FAQ

How early does white marsh marigold flower?
It often starts in late winter or early spring, with peak flowering in March and April in the UK.

Can it sit in shallow water?
Yes. It copes with wet soil and shallow water at the edge, as long as the crown is not buried too deep.

Will it spread?
It forms a clump and can self-seed in wet ground. Lift and divide if you want to keep it in bounds.