Aruncus
Aruncus dioicus
Cream-colored froth on a frame the size of a shrub — one of the few things that will properly fill a damp, shaded corner.
- Type
- Flower · Perennial
- Botanical family
- Mixed / other
- Foliage color
- Green
- Flower color
- White
- Sunlight
- Partial to full shade.
- Watering
- Keep it consistently moist.
- Feeding
- An annual mulch in spring is enough.
- Frost tolerant
- Yes
- Flowering
- June
- Pruning
- Cut it back twice — once after flowering, again in autumn.
- Overwintering
- Hardy; mulch the crown anyway for good measure.
- Mar–Jun Spring Growth
- Jun–Aug Flowering
- Aug–Nov Growing
- Nov–Dec Leaf Fall
- Jan–Mar Leaf Fall
- Plant spacing
- 3 ft 11 in
- In-row spacing
- 3 ft 11 in
- Between rows
- 4 ft 11 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
- 4–6 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 crown becomes tough and woody with age, so dividing an old plant is a job for a saw rather than two forks.
The habit is Aruncus’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.
Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. companion plant
- Parasitic wasps Braconidae & TrichogrammaHunts Sawfly
Tiny, stingless wasps that lay eggs in or on caterpillars, aphids, and moth eggs — the white cocoons riding a hornworm are their calling card, so leave that caterpillar be. Umbel flowers with shallow nectar keep the adults fuelled.
- Spined soldier bug Podisus maculiventrisHunts Sawfly
A predatory stink bug — same shield outline as the pest, but with a sharp spine at each shoulder and a beak it uses to spear caterpillars and beetle grubs. Learn the spines before you squash a shield bug, because this one is on your side.
- Tachinid fly TachinidaeHunts Sawfly
Bristly, house-fly-lookalike parasitoids that lay eggs on caterpillars, beetle grubs, and earwigs — the maggot consumes the host from within. Adults sip nectar from shallow umbels and daisies.
Green-leaved flowers, like this one.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com