Creeping phlox (Phlox subulata) does not bloom all summer. This low-growing, mat-forming perennial is highly valued for its dense, needle-like, semi-evergreen foliage that remains attractive throughout the year. The plant’s primary feature is a massive, short-lived spring display that creates a vibrant, carpet-like cover over the ground.
Understanding the Single Spring Bloom
The bloom cycle of creeping phlox is a concentrated event that lasts for only three to four weeks. This profuse flowering usually occurs between mid-April and late May, depending on the specific climate and geographic location. During this period, the plants are so completely covered in tiny, five-petaled flowers that the underlying foliage is often barely visible.
Warmer regions may see the blooms appear earlier, sometimes starting in March, while cooler zones might not experience the display until late May or early June. This intense flowering expends a large amount of stored energy. Once the flowers fade, the plant’s energy shifts toward strengthening its root system and maintaining its dense, green groundcover.
Essential Care After Flowering Ends
Once the brilliant spring color fades, post-bloom care is important for maintaining the plant’s health. The most beneficial action is shearing, which involves lightly pruning the plant to remove spent flower heads and a small amount of foliage. Using hedge shears or a string trimmer to cut back the plant by about one-third encourages denser, healthier growth and prevents the stems from becoming woody or sparse.
This light pruning redirects the plant’s energy away from setting seed and into developing new lateral shoots, ensuring the phlox maintains its tight, mat-like form. After shearing, a light application of a balanced, slow-release fertilizer or compost can help replenish nutrients. While creeping phlox is drought-tolerant once established, supplemental water during prolonged summer dry spells will keep the foliage looking its best.
Why Creeping Phlox Is Not a Continuous Summer Bloomer
The expectation of summer flowers often arises from confusion between Phlox subulata and other members of the Phlox genus. Creeping phlox is genetically programmed to flower once in the spring as soon as weather conditions permit. Its growth habit is low-lying and spreading, which makes it an excellent choice for rock gardens and slopes.
Many people mistakenly associate it with Tall Garden Phlox (Phlox paniculata), which is an entirely different species. Tall Garden Phlox has an upright growth habit, reaching two to four feet, and is a true summer bloomer, producing large flower clusters from mid- to late summer. Woodland Phlox (Phlox stolonifera) is another low-growing variety, but it prefers shade over the sun enjoyed by creeping phlox and has a different bloom schedule.