Description of Calla palustris (Bog Arum)

Calla palustris is bog arum, also called water arum. It’s a low marginal with glossy leaves and a white spathe in late spring. It’s a great plant for pond shelves where you want something neat and a bit different from irises.

Appearance

It makes heart-shaped glossy leaves from creeping rhizomes. In spring to early summer it produces a white spathe around a yellow central spike. Height is usually 15 to 30cm, but it can spread into a patch.

Care Guide

It wants cool, wet roots and does best in acidic to neutral conditions.

• Sun: Full sun to part shade.
• Soil: Aquatic compost or peaty mud.
• Water: Shallow water or saturated mud.
• Control: Use a basket to keep the patch tidy.
• Tidy: Remove old leaves in late winter.

It often looks best when allowed to form a small colony rather than a single plant.

Suitability for Bog Garden

This suits bog gardens with a pond shelf or permanently wet hollow. It also works at the edge of an acidic bog, as long as it stays wet.

Avoid dry edges where the rhizomes can stall.

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