How to grow phlox

Creeping Phlox (Phlox subulata) is a low-growing, mat-forming perennial that produces a dense carpet of colour in spring, with masses of star-shaped flowers in shades of pink, purple, blue or white. Native to the mountainous regions of North America, it thrives in full sun and well-drained soil, making it a perfect choice for rock gardens, slopes, walls, and the front of sunny borders. Once established, it is drought tolerant and extremely low maintenance, spreading gently without becoming invasive. Fully hardy and evergreen in many areas, Creeping Phlox also offers useful year-round ground cover and is a magnet for early pollinators when in bloom.

This low maintenance perennial is hardy to around -20C and can be left outside all year round without winter protection. Here's how to get your creeping Phlox off to the best start:

How to plant:

Creeping Phlox are supplied as 9cm root balls in autumn and should be planted within a week of delivery.
Your Phlox subulata root ball plant will require water and light as soon as possible after delivery. If you are unable to plant immediately, the root ball can be positioned in shallow water in a bright place so that it can remain hydrated and healthy.
Pot root balls into temporary 10-15cm diameter pots, using a good quality multi-purpose compost. Root balls can also be planted directly into a well-cultivated border with well-drained soil. If planing directly into borders, avoid planting them into a space which will become over-crowded by more established plants because new plants may struggle to compete with large, more established neighbouring plants. Also avoid planting directly into challenging soil types.
Plant Phlox subuluta root balls so that the root system is fully submerged in the compost, leaving any young shoots/leaves, buds or stems exposed above the soil surface. Water well after planting and continue watering regularly whenever the soil feels dry.
Grow them on in a sheltered spot outside, standing pots on a porous surface so that excess water can drain away freely. They can be transplanted to suitable growing positions in spring, or once growth is established and the roots begin to emerge from the bottom of the pots.
If planting Phlox root ball plants directly into a clear space in a border, choose a sheltered position in full sun or partial/light shade on any moist, well-drained soil. Once established, it can tolerate short periods in dry conditions but it's important to maintain regular watering in the first year. If growing as grown cover, space the plants 20-40cm apart to form a group. Add multipurpose compost to each planting hole to help the new roots grow and water well afterwards. Mark with a plant label or cane so you can identify and monitor the new plant in the border, ensure it is hydrated, keep the area clear of competing weeds/plants.
Creeping Phlox is hardy to around -20C and does not require winter protection in most areas.
There should be some buds/shoots visible on the plants when they are supplied. The plants will remain dormant with little growth over winter but will start to grow and produce leaves in spring. Perennials may not flower in the first year.

Aftercare

Creeping Phlox can be slow to establish, and may take 2-3 years to spread out to form a ground cover, depending on how far apart the plants are spaced. It may not flower in the first year, but will develop a mat of creeping leaves.
After flowering, lightly trim back spent blooms and straggly stems to maintain a compact shape and encourage fresh growth.
Creeping Phlox may partially die back in autumn, at which point you remove old stems to tidy up the display. New stems and foliage will emerge from the base in spring.
Older clumps that become woody in the centre can be divided or rejuvenated by lifting and replanting healthy outer sections in early autumn or spring.
Ensure good drainage to prevent root rot, and avoid waterlogging during winter months.