Dwarf phlox is among my all-time favourite rockery plants, its petite colourful starry flowers cascading over walls, filling in gaps in the scree bed or brightening up alpine troughs in an array of colours, from white to deep pinks and purples. If you give it a good trim after flowering it will return again the following year in all its glory.

Good varieties include P. Chattahoochee', a low-growing lilac variety with a central reddish-purple eye, flowering in clusters in early summer. P subulata is in abundance at garden centres, a carpeting plant flowering in April and May, while P. douglasii (alpine phlox) blooms a little later. Other named varieties include Temiscaming' (red) and GF Wilson' (pale purple).