Butterfly bush
Buddleja davidii
also called buddleja, buddleia
Cut to knee height every March and it repays you by July — the harder the prune, the better the flowering.
- Type
- Shrub · Perennial
- Botanical family
- Mixed / other
- Foliage color
- Silver and gray
- Flower color
- Purple and violet
- Sunlight
- Full sun, if you want flowers worth having.
- Watering
- Drought-tolerant; only newly planted shrubs need watering.
- Feeding
- A compost mulch after the spring cut; it rarely asks for feed.
- Frost tolerant
- Yes
- Flowering
- July
- Pruning
- Cut hard back to 30-60cm in March, and deadhead as the flowers go over.
- Mar–Jul Bud Break
- Jul–Sep Flowering
- Sep–Oct Growing
- Oct–Dec Leaf Fall
- Jan–Mar Leaf Fall
- Plant spacing
- 8 ft 2 in
- In-row spacing
- 8 ft 2 in
- Between rows
- 10 ft 3 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
- 12–16 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.
The habit is Butterfly bush’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.
- Generally trouble-free No notable pest or disease problems when grown in the right conditions — one of the easy ones.
Lavender, Verbena, Echinacea, Sedum
Shrubs, like this one.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com