Flowering rush (Butomus umbellatus)

Flowering Rush (Butomus umbellatus) is a striking British native marginal aquatic plant featuring upright, slightly twisted grassy leaves that start bronze-purple before maturing to dark green. From June to July, it produces beautiful umbrella-like clusters of fragrant, rosy-pink flowers, each about 2cm wide, adding delicate charm to any pond or wetland area.

A fantastic choice for wildlife, it provides essential egg-laying sites for dragonflies, perching spots for adults, and sturdy stems for larvae to climb out of the water. Happy in full sun, this nutrient-hungry plant thrives in shallow water (with its crown at least 10cm below the surface) or can adapt to boggy ground.

To keep it flourishing, avoid overcrowding – divide every few years and feed with slow-release fertiliser in spring.

Also known as Grass Rush, it spreads by rhizomes but may stop flowering if pot-bound, so give it plenty of room to grow.

Details

• Native: Yes
• Sun: Full Sun
• Depth: 5 – 45
• Height max: 120cm
• Spread max: 60cm
• RHS PFP: Yes
• Other: Great for Dragonfly

Care Instructions

Cut back after flowering and divide every couple of years to prevent overcrowding and encourage healthy blooms. For best growth, plant in shallow water (at least 10cm deep) and feed with slow-release fertiliser in early spring. Avoid letting it become pot-bound to ensure continuous flowering.

Repotting Instructions

Can also be planted in very wet soil – do not allow to dry out.

9cm marginal plants require potting into a mesh basket. Place in a pond no deeper than 1/3 maximum recommended planting depth to allow the plants to establish.

1ltr marginal plants do not require repotting but will benefit from a bigger basket, there is no need to remove the mesh basket. Place in pond no deeper than 1/2 maximum recommended planting depth to allow the plants to establish. Plants over 60cm height growth will benefit from repotting into a larger mesh basket or should be planted in gravel to prevent them from falling over in a breeze.

3ltr and 5ltr plants do not require repotting; there is no need to remove the mesh basket. Place on the shelf of the pond at the required depth.