Spacing & sowing

Plant spacing

6 ft 7 in

In-row spacing

6 ft 7 in

Between rows

8 ft 2 in

Square-foot density

Not suited to SFG

Growing

Type

Shrub · Perennial

Botanical family

Mixed / other

Sunlight

Morning sun with afternoon shade — keep it off a hot south wall.

Watering

Water deeply and often, and mulch to hold the moisture in.

Feeding

A balanced feed in spring; ericaceous feed for blue flowers.

Frost tolerant

Yes

Flowering

June

Pruning

Prune according to type, and leave the old heads on over winter for protection.

Through the year

• Mar–Jun Bud Break
• Jun–Aug Flowering
• Aug–Oct Growing
• Oct–Dec Leaf Fall
• Jan–Mar Leaf Fall

Companions

Hostas, Ferns, Astilbe, Heuchera

Pests & problems

• Scale insects Hydrangea scale
• Vine weevil Adults notch leaf edges at night; their plump C-shaped grubs devour roots, especially in containers. Hand-pick adults after dark and water in biological nematodes in late summer.
• Honey fungus A fatal root disease of woody plants: white fungal sheets under the bark and honey-colored toadstools at the base. Remove the plant with as much root and stump as possible.
• Powdery mildew A white dusty coating over leaves and shoots when roots are dry but the air is humid. Keep plants watered and mulched, prune for airflow, and remove the worst leaves.
• Frost damage Frost damage to the flower buds

Garden allies

Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. ★ companion plant

• Beneficial nematodes Steinernema & Heterorhabditis spp.
  Hunts Vine weevil

  Microscopic worms watered onto damp soil that hunt down soil-dwelling grubs and release a bacterium that kills them within days. Timing is the whole thing: warm, damp soil and a small target grub, which means late summer for most of what they are used against.

• Frogs & toads Anura
  Hunts Vine weevil

  A resident toad works the beds every night for slugs, cutworms, and weevils. Recruit them with water — even a sunken basin pond — plus damp shade and an upturned-pot toad house; skip the slug pellets that poison their prey.

• Ground beetle Carabidae
  Hunts Vine weevil

  Fast, glossy night hunters that patrol the soil surface for slugs, cutworms, and root-fly larvae. Give them daytime cover — thick perennial edges, stepping stones, a log — and skip the tillage that wrecks their burrows.

  Plant nearby LavenderMintThyme
• Hedgehog Erinaceus europaeus
  Hunts Vine weevil

  A European animal, and worth saying so plainly: there are no hedgehogs in North America, and the ally that does the same night shift here is the toad, the opossum or the ground beetle. Where they do occur, cut a gap in the fence and skip the pellets.

• Hoverfly Syrphidae
  Hunts Scale insects

  Bee-mimicking flies whose legless larvae graze aphid colonies clean while the adults pollinate. A ribbon of shallow, nectar-rich flowers kept in bloom all season recruits wave after wave of them.

  Plant nearby CalendulaChamomileFennelFrench marigoldPhaceliaSweet alyssum
• Ladybird (lady beetle) Coccinellidae
  Hunts Scale insects

  The gardener’s favorite ally: adults and their alligator-shaped larvae each eat thousands of aphids, plus scale, mealybugs, and other soft-bodied sap-suckers. Grow flat, open flowers for the adults and never spray a colony that ladybird larvae are already working.

  Plant nearby CalendulaCilantroCosmosDillFennelYarrow