Perennial
Garden phlox
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Flowers | Flowers in July | Flowers in August | Flowers in September | |||||||||
| Plant | Plant in March | Plant in April | Plant in September | Plant in October | ||||||||
| Prune | Prune in May | Prune in October | ||||||||||
| Looks good | Looks good in July | Looks good in August | Looks good in September |
Overview
Upright stems carry large, rounded heads of flat, five-petalled flowers with a sweet, peppery scent that is strongest in the evening. Colours run from white through pink and lavender to deep magenta, many with a contrasting eye. The pure white 'David' has an excellent reputation for shrugging off mildew, 'Blue Paradise' shifts from blue to violet as the light changes, and 'Bright Eyes' is pale pink with a crimson centre. Moths and butterflies visit at dusk.
Where to grow garden phlox
Phlox wants fertile, moisture-retentive soil and dislikes drying out. Full sun works in the north and in damp gardens; elsewhere, a spot with afternoon shade keeps it fresher. Avoid hot, dry corners against walls, where mildew thrives.
Planting
Dig in plenty of compost and plant 45–60 cm apart in spring or autumn, giving each clump space for air to move between stems. Water well until established.
Care through the year
Spring
Mulch thickly with compost once the soil has warmed and is moist.
Summer
Water deeply in dry spells and deadhead faded heads for side-shoot flowers.
Autumn
Cut stems down once they brown; divide congested plants.
Winter
Nothing to do; plants are fully hardy.
Pruning
In late May, cut the front third of stems back by half; they flower later and shorter, extending the season. Thinning a clump to five or six strong shoots in spring also improves air flow.
Propagation
Divide every three or four years in autumn or spring. Root cuttings taken in winter avoid passing on stem eelworm.
Common problems
Powdery mildew is the main issue, usually triggered by dry roots; mulching and watering help more than anything. Stem eelworm causes twisted, swollen shoots; dig up and bin affected plants. Slugs nibble young spring growth.
Guides to the problems most likely to affect garden phlox:
Something else wrong? Diagnose it by symptom.
Month-by-month reminders
Jobs for this plant come round in March, April, May, September and October. Each month page lists everything else worth doing in the garden at the same time.
Related plants
Sources
Botanical names follow Kew's Plants of the World Online; growing attributes were checked against the references below. Text is our own. See our editorial policy.