With such a wide range of phlox available, there’s one for most garden situations, from dry to moist soils, in full sun to full shade. Whether groundcover or towering perennial, evergreen or deciduous, phlox comes in an overwhelming array of colours, heights, forms and bloom times, too. Perhaps best of all, it’s a terrific companion plant. In shades of blue, white and pink, for example, they tone down hot yellows and oranges and buddy up to other cool-coloured perennials.
Low, spring-flowering groundcovers such as woodland phlox combine exceptionally well with early bulbs, including the dwarf narcissus ‘Tête-à-Tête’, as well as native wildflowers.
Leading the parade of summer- and early-fall-flowering plants is garden phlox, a classic back-of-the-border specimen.
Many phloxes are sweetly scented, despite the genetic tinkering that’s produced the newer cultivars. (In Britain, some are called summer lilacs because of their heady fragrance.) Before purchasing, give them the sniff test—some are more fragrant than others. They also make great cut flowers.
- Ensure good drainage for groundcover types, such as Phlox subulata, growing in full sun.
- Mulch young plants with shredded bark or small wood chips to suppress weeds, help retain soil moisture and moderate soil temperatures; water during drought in full-sun situations.
- Improve air circulation, especially around older varieties, which are susceptible to powdery mildew; thin out a few shoots in spring to increase air movement or replace them with newer, mildew-resistant varieties, such as ‘Natascha’.
- Deadhead to prolong bloom time and prevent self-seeding.
- Keep spring-blooming groundcover types compact by shearing after flowering.
- Pinch back stems of very tall cultivars in early summer to encourage the formation of flowering side shoots.
- Divide in early fall.