© RHS/Joanna Kossak


Specialist phlox

Often diminutive, these phlox fall into two groups with specific needs, preferring either a sunny rock garden or a bed in cool dappled shade. In a nutshell, they like either alpine conditions or woodlands.


Often forming low, sometimes evergreen, cushions of foliage or tumbling cascades, these phlox have sheets of flowers. These are rounded white, pink or purple, often scented, and appear in loose clusters that can cover the plant. Heights range between 7.5-30cm (3in-1ft).


The plants in this group need either gritty, sharply-drained soil in full sun (including Phlox adsurgens, P. caespitosa and  P. douglasii) and or cool, moist soil in light shade (P. divaricata).


The pholx that like well-draining soils, resent their roots being waterlogged in winter. Several species, like P. stolonifera that like moist conditions also need a soil with acidic pH (so typically pH5.5-6.5).

Did you know?

Many rock garden phlox, such as P. caespitosa like sharp drainage and can be successfully grown in containers in an unheated greenhouse, which shelters them from excessive rainfall.

Growing guide

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Useful advice

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Rock gardens: plants

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Sink and trough gardening

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