Butomus umbellatus
Flowering rush
Common names: Grass rush
At a glance
- Light
- Full sun
- Pot size
- from 50 l
- Lifespan
- Perennial
- Flowering
- Jun–Aug
- Hardiness
- Hardy
- Origin
- Native to Germany
Photo: Christian Fischer · CC BY-SA 3.0 · Source
Description
Butomus umbellatus, commonly known as flowering rush, is a native shoreline perennial suited for the shallow-water zone of a garden pond. It produces reed-like, tapering leaves that extend into long stems, which open into panicle-like inflorescences: numerous individual pink to light‑pink flowers cluster together like a small fireworks display. From June to August it reliably attracts bees and hoverflies. The plant grows in dense clumps in shallow water and is winter hardy; its roots survive frost as long as they remain below the ice line.
Care instructions
Plant in baskets filled with loamy pond soil and position 5 to 20 cm below the water surface. It prefers full sun and still to gently flowing water; at shaded sites flowering is noticeably weaker. Trim wilted flower stems just above the waterline to keep the clump compact and encourage new shoots. Divide the plant every three to four years in spring when new growth appears to maintain vigor and prolific blooming. In winter leave it in place as long as the root ball stays frost‑free in the water; no additional protection is needed.
The care notes were machine-translated from German.
Garden year
FloweringJun–Aug
Soil & site
Soil pH
Soil type
moist, nutrient-rich, loamy, clayey
The flowering rush prefers to stand in shallow water or in the permanently wet margin of a pond or stream. It needs a nutrient-rich, loamy to clayey base that holds water for a long time. A sunny to partly shaded spot at the water's edge is ideal, because that is where it develops its most beautiful flower umbels.
Feeding
Medium feeder
Months
Apr–May
In spring the flowering rush welcomes a helping of well-rotted compost, which you work carefully into the bank mud. For potted cultivation in a pond basket, a special slow-release fertiliser for aquatic plants, mixed into the soil, is enough. It needs no further feeding; a nutrient-rich site usually carries it through the year by itself.
Overwintering
The flowering rush is hardy and dies back with its foliage in autumn, while the rootstock survives in the mud. As long as the pond does not freeze to the bottom, it needs no extra protection. In shallow basins or containers, to be safe, move the pot deeper into the water or keep it cool and frost-free.
Propagation
Methods
- Division
- From seed
The easiest way to propagate the flowering rush is to divide the rootstock in spring and set the pieces straight back into shallow water. It tolerates division well and shoots again quickly afterwards. If you want to try seed, sow the ripe seeds straight after harvest in wet soil and keep them constantly moist; germination then takes considerably longer than with division.
For your garden
Grow Flowering rush yourself
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