Creeping phlox (Phlox subulata) is a popular spring-blooming perennial loved for its mats of bright, colorful flowers. This low-growing phlox, also known as moss phlox, produces flowers in shades of white, pink, red, purple, orange and blue in spring and thrives in full sun and well-drained soil. But sometimes creeping phlox fails to bloom as expected, leaving gardeners scratching their heads.
If your creeping phlox isn’t blooming, don’t despair! With a little detective work, you can get your phlox flowering again Here are some of the most common reasons creeping phlox doesn’t bloom and what to do about it
Not Enough Sunlight
Creeping phlox needs at least 6 hours of direct sunlight per day to bloom well. While partial shade is okay, too much shade will result in weak, leggy growth and few or no flowers. Evaluate your phlox’s location. Is it getting sunshine most of the day? Keep in mind the amount of sun changes with the seasons as the sun moves across the sky. If your phlox isn’t getting enough light now, it may need to be moved to a new spot. South, east or west-facing sites are ideal. Morning sun is better than afternoon sun.
Improper Growing Conditions
In addition to ample sunlight, creeping phlox requires well-drained soil and consistent moisture. Poor, heavy soil or overly wet conditions can lead to root rot and other problems. Make sure your phlox isn’t planted in an area where water collects. Improve drainage by mixing in compost or small gravel. Mulch around plants to maintain consistent moisture. Let the soil dry slightly between waterings.
Hot, dry sites can also inhibit flowering. Creeping phlox thrives in zones 3-8 and appreciates afternoon shade in warmer climates. Ensure plants get at least 1-2 inches of water per week if rainfall is inadequate.
Pay attention to soil pH as well Creeping phlox does best in slightly acidic to neutral soil with a pH of 60-7.0. Use an at-home soil testing kit to check pH and amend accordingly.
Lack of Fertilization
Like most flowering plants, creeping phlox needs nutrients to bloom its best. Fertilize plants once a year in early spring with a balanced fertilizer such as 10-10-10. Organic options like compost or bone meal also add nutrients. Avoid high-nitrogen fertilizers which promote leafy growth over flowers.
If you’re not sure when your phlox was last fertilized, go ahead and add an all-purpose fertilizer now. It’s not too late to get blooms this year with the right nutrition.
Overcrowding
After several years, creeping phlox may stop blooming well due to overcrowding. The plants grow together in thick mats and become rootbound, preventing new shoots and flowers from emerging. Every 2-3 years, lift and divide congested clumps in early spring. Replant divisions 12-18 inches apart. This allows air circulation and stimulates new growth.
You can also propagate creeping phlox by taking cuttings in summer. Clip off healthy stem tips, remove lower leaves, dip in rooting hormone and stick in potting mix. Keep cuttings watered until rooted then transplant outdoors.
Improper Pruning
Hold off on pruning creeping phlox until after it blooms. Deadheading or cutting plants back too early can remove flower buds and delay blooming. To maximize flowers, wait to trim phlox until early summer after the initial flush of blooms is finished. Then cut back stems by about one third to encourage reblooming and a flush of new growth. Avoid cutting old growth too far down which can weaken plants.
Pests or Diseases
Sometimes failure to thrive and bloom is due to damage from pests or diseases. Powdery mildew is a common phlox problem, coating leaves and flowers with white fungal growth. Spider mites, thrips and leafminers may chew on foliage.
Check phlox closely for signs of infestation. Remove affected parts immediately. Use insecticidal soap, neem oil or horticultural oil to control small insect pests. Apply fungicides labeled for powdery mildew. Improve air circulation between plants to discourage diseases.
Age of Plants
Like all perennials, creeping phlox slows down as it ages. Optimum flowering is during the first 2-4 years. Gradually flowers decline and the plants become woody and spread out. After 4-6 years, it’s best to replace overgrown patches of phlox with freshly propagated new plants to ensure abundant blooms.
Harsh Winter Damage
Extreme winter cold can injure or kill creeping phlox. Dieback, browning of foliage and failure to bloom can be signs cold damage. Unfortunately, there isn’t much you can do except cut back spent stems and hope for renewed growth when warmer weather arrives. Provide winter mulch in future years for added protection.
Improper Variety
Some varieties of creeping phlox bloom more prolifically than others. ‘Red Wings’, ‘Emerald Blue’, ‘Crimson Beauty’ and ‘Candy Stripes’ are excellent repeat bloomers. Make sure you haven’t mistakenly purchased Garden Phlox (Phlox paniculata) which flowers in summer rather than spring. Check plant tags to ensure you have a highly floriferous creeping phlox variety.
Give it Time
Patience is key when plants underperform. Continue providing creeping phlox with proper care and growing conditions. Bloom time can vary year to year depending on weather. It may take a season or two for your interventions to solve the problem and get the phlox flowering abundantly again.
With the right location, soil, moisture, nutrition and maintenance, you can get your creeping phlox to bloom once again. Take time to evaluate its needs and make cultural improvements. If necessary, replace older plants with young, healthy ones. With proper care, this colorful, flower-carpeting phlox will brighten up your garden for years to come.
More Than Just Flowers…
Even when not in bloom, this mat-forming groundcover still looks pleasing in the landscape, maintaining a fresh green hue that remains attractive until it dies back in winter. Its awl-shaped (a tool commonly used for working with leather) leaves form a cushion and often resembles moss; hence, its common name: moss phlox. Another wonderful quality of creeping phlox is it can tolerate light foot traffic. Consider adding creeping phlox to pathways or between patio pavers.
Low Maintenance, Weed Smotherer
Creeping phlox is not only durable, but it’s also remarkably easy to care for. Not only does it tolerate a wide range of climates and tricky soils, but it doesn’t seem to be plagued by powdery mildew as harshly as many other phlox does. On top of its ease of care, it can also take away an often dull and time-consuming garden task: weeding. Creeping phlox’s dense mat-like habit makes it great for suppressing weeds, giving you more time to enjoy your garden.
You’re in luck if you came here to learn how to grow creeping phlox! Phlox subulata does best in full sun and well-drained soil. Even though it can grow in dappled light, like a sunny spot in a woodland garden, or in very hot and humid places, it usually flowers best where it gets full sun. With a little care, creeping phlox will thrive in your landscape.
Creeping phlox likes well-drained soil enriched with organic matter. Plants prefer soil with a slightly acid to neutral pH.
Creeping phlox grows best in full sun (or partial shade in the South). For best flower production, avoid too much shade.
Low to Average. Mature, established creeping phlox can tolerate some drought. Generally needs watering weekly, especially during hot summers or periods without rain.
Phlox only needs a general-purpose slow-acting granular fertilizer worked into the soil around the plants in the spring. This will take care of them for the season.
No special care is needed to protect creeping phlox in the winter. Leave its standing in winter, and clean up spent foliage in spring before bloom.
While pruning is optional for creeping phlox, it can help encourage rebloom. To do so, cut back stems after flowering has finished by half. This will promote dense growth and attractive habit for the summer months, making it a more attractive groundcover. This will also encourage some fall rebloom, though deadheading is not required.
How Long Does Creeping Phlox Bloom
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