Filipendula
Filipendula ulmaria
Wet ground is not a problem here but a requirement — let the soil dry out and mildew follows.
- Type
- Flower · Perennial
- Botanical family
- Mixed / other
- Foliage color
- Green
- Flower color
- White
- Sunlight
- Full sun or partial shade.
- Watering
- Wants soil that stays consistently moist, even wet.
- Feeding
- No feeding needed on moist, fertile ground.
- Frost tolerant
- Yes
- Flowering
- June
- Pruning
- Cut back once the flowers are over.
- Overwintering
- Fully hardy; it dies back to the ground on its own.
- Mar–Jun Spring Growth
- Jun–Aug Flowering
- Aug–Nov Growing
- Nov–Dec Leaf Fall
- Jan–Mar Leaf Fall
- Plant spacing
- 23.6 in
- In-row spacing
- 23.6 in
- Between rows
- 2 ft 6 in
- Square-foot density
- Not suited to SFG
- Root system
- Clumping rhizomes
- Working depth
- 6–16 in
- Can reach
- 24 in down where the soil allows
- Spread
- 24 in–3 ft across, about 1–1.5× the width of the plant
- Shallowest pot
- 10 in of soil
The clump widens a little each year from a shallow rhizome that likes to sit at or just under the surface. When the middle goes bare and woody, lift the whole thing, keep the young outer pieces and throw the centre away.
The habit is Filipendula’s own; the figures are what that habit usually comes to at this size, not a measurement of this species. Roots follow the soil either way: a compacted pan, a high water table or heavy clay stops them well short of any of it, and deep open ground lets them go further.
- Powdery mildew Powdery mildew when the soil dries out — keeping it moist is the fix
- Rhizomes that spread, and may need containing in a small garden
Flowers, like this one.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com