Grevillea
Grevillea spp.
Ordinary fertilizer is what kills it — phosphorus is the poison here, and lean, free-draining acid soil the cure.
- Type
- Shrub · Perennial
- Botanical family
- Mixed / other
- Foliage color
- Green · Silver and gray
- Flower color
- Red
- Sunlight
- Full sun; it will take partial shade but flowers less for it.
- Watering
- Water weekly while it establishes, then leave it be — drought-tolerant once settled.
- Feeding
- A low-phosphorus native plant fertilizer, in spring only.
- Frost tolerant
- Yes
- Flowering
- March
- Pruning
- Tip-prune lightly after each flush of flower.
- Mar–Mar Bud Break
- Mar–Dec Flowering
- Dec–Dec Dormancy
- Jan–Mar Dormancy
- 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
- Root system
- Woody and fibrous
- Working depth
- 12–24 in
- Can reach
- 3 ft down where the soil allows
- Spread
- 10–13 ft across, about 1.5–2× the width of the plant
- Shallowest pot
- 20 in of soil
A shallow woody framework with the fine feeding roots in the leaf litter above it. Those feeders are mostly under the outer half of the canopy rather than against the stem, which is where water and feed should go.
Proteoid roots, dense mats of fine rootlets in the surface litter, let it mine phosphorus from soils that carry almost none. Ordinary fertilizer overwhelms that machinery and kills the plant, so feed it a native mix or nothing.
The habit is Grevillea’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.
- Cabbage looper Grevillea looper caterpillar
- Scale insects Immobile brown or white bumps fixed to stems and leaf undersides, sucking sap and weakening growth. Wipe off with a damp cloth or dab with horticultural soap; watch for the sooty mold that follows.
- Phytophthora root and foot rot Phytophthora root rot, brought on by overwatering or waterlogged soil
- Phosphorus deficiency Phosphorus toxicity from standard fertilizers
Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. companion plant
- Hoverfly SyrphidaeHunts 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.
- Ladybird (lady beetle) CoccinellidaeHunts 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.
- Parasitic wasps Braconidae & TrichogrammaHunts Cabbage looper
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 Cabbage looper
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.
Lavender, Rosemary, Agapanthus, Westringia, Kangaroo Paw
Shrubs, like this one.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com