Garden phlox
Phlox paniculata
also called border phlox
Worth the trouble in a late border, but only where air moves freely — crowded plants mildew every year.
- Type
- Flower · Perennial
- Botanical family
- Mixed / other
- Foliage color
- Green
- Flower color
- Pink
- Sunlight
- Full sun to light shade, in a spot where air moves freely.
- Watering
- Keep the soil moist, and water at the base so the foliage stays dry.
- Feeding
- A balanced feed in spring, with compost spread over the roots.
- Frost tolerant
- Yes
- Flowering
- July
- Pruning
- Thin each clump to five or six shoots in spring, and cut the stems down in autumn.
- Mar–Jul Spring Growth
- Jul–Sep Flowering
- Sep–Oct Growing
- Oct–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 Garden phlox’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.
Delphiniums, Roses, Grasses, Monarda
Green-leaved flowers, like this one.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com