Phlox is one of the mainstays of the herbaceous border – in late summer it provides waist-high sheets of colour and scent. Each flat-faced flower measures about 1 in. across, nothing very special as individuals but most impressive when seen in large trusses above the narrow, pointed. Prolific flowering is the hallmark of this garden favourite and these days you can buy almost any shade from white to deep purple. It is not a particularly fussy plant – it likes a moist soil (add or peat when planting) and the flower colours are at their best when it is grown in light shade. Mulch in spring and water in summer if the weather is dry. Some form of support should be provided if the site is exposed and the require to be cut down to a couple of inches above ground level in late autumn when flowering is over. No cultural difficulties, but there is one hidden enemy which can cause havoc. The microscopic phlox eelworm shrivels leaves and distorts the stems. Young shoots are killed and older ones are stunted – look for the tell-tale narrow, strap-like foliage. There is nothing you can do but dig up and burn the plants – do not replant with Phlox, Gypsophila nor for at least three years.
VARIETIES: The popular Garden Phlox is P. paniculata (P. decussata) – height 2-4 ft. Spacing W2 ft.
Flowering period: July-October. Large garden centres and comprehensive catalogues offer an abundance of varieties; you will find some or all of the following – ‘Brigadier’ (orange-red), ‘Balmoral’ (rose-lavender), ‘The King’ (violet-purple), ‘White Admiral’ (white), ‘Starfire’ (deep red), ‘Fairy’s Petticoat’ (mauve) and ‘Endurance’ (salmon-orange). For extra brightness you can plant the purple-flowered ‘Harlequin’ which has variegated leaves or you can grow varieties with mirror-imaged blooms -’Graf Zeppelin’(red-eyed white) and’Sweetheart’(white-eyed red ). All these varieties of P. paniculata bear their blooms in rounded clusters – for a different arrangement grow the much less common P. maculata which bears its blooms in long columns. Its basic details are height 2-3 ft. Spacing 1.5 ft.
Flowering period: July-September – the best-known variety is ‘Alpha’(pink).
SITE AND SOIL: Any moisture-retentive garden soil will do – thrives in sun or light shade.
PROPAGATION: Divide clumps in autumn or spring; takein winter.