Phlox subulata 'Emerald Blue' in Carina Wong's front garden.
Mom always referred to Phlox subulata as Creeping Phlox, but Moss Phlox seems to be the common name I hear more frequently these days. Phlox subulata flowers for a number of weeks in early spring and forms a low mound of green, needle-like foliage. The star-shaped flowers have five petal-like lobes that are notched on the outside edge.
The native form of Phlox subulata can be found on rocky, sandy slopes and open woodlands in Michigan, Ontario and in a large area that runs from New York south to Tennessee. Modern cultivars come in an array of colors including pinks, reds, purples, white and white striped with hot pink.
Moss Phlox is fairly adaptable to a variety of soil types, but the soil must be well-drained. I can't stress this enough. Nothing will kill your Moss Phlox quicker than cold, soggy soil in the wintertime. If your soil isn't free-draining, amend it with fine pebbles, sand and organic material.
Moss Phlox prefers evenly moist conditions, so water young plants until they are established. Even after Moss phlox has settled in, it still may need supplemental watering during periods of prolonged drought.
Full sun will produce the best show of flowers. In southern gardening zones, however, Moss Phlox will appreciate a little respite from the heat of the afternoon sun.
Phlox subulata 'Emerald Blue' in the garden of Marion Jarvie in Thornhill, ON.
A cushion of lavender-pink flowers in Marion Jarvie's garden.
Here pink Moss Phlox mixes with white Arabis in the gravelly soil of the rock garden at the Agricultural Campus of Dalhousie University in Truro, N.S.
The somewhat messy appearance of Phlox subulata after it flowers.
Ongoing Care
After the spring flowers fade and turn brown in late spring, Phlox subulata can look a bit scruffy and untidy. Give your plant a light haircut to remove the spent flowers and promote fresh foliage. If you're lucky, you might even see a little bit of reblooming.
After a few years, the plant's stems can become woody and will produce fewer and fewer flowers. To stimulate fresh growth and more springtime blooms, cut the stems back by half.
If you want to divide your Moss Phlox, do it in early spring just after they have finished flowering.
Cultivars to Collect
In the pictures below, one cultivar may seem pretty much like any other with the exception of the flower color. There are differences:
Some cultivars grow more quickly than others. The needle-like foliage can also be finer and more dense on some cultivars. Finally, the flowers vary in size. When you do your shopping, you'll note these distinctions much better than you will in my pictures.
Phlox subulata 'Emerald Blue' is a popular cultivar for all the right reasons and is a great one to start with.
Phlox subulata 'Violet Pinwheels' has intense violet-purple flowers in early spring. Plant in full sun. Average, well-drained soil. Height: 10-15 cm (4-6 inches), Spread 60-90 cm (23-35 inches). USDA zones:3-9.
Phlox subulata 'Pink Emerald' has pink flowers with a hot pink eye. Plant in full sun. Average, well-drained soil. Height: 15-20 cm (6-8 inches), Spread: 30-45 cm (12-18 inches). USDA zones:3-9.
Phlox subulata 'Purple Beauty' has magenta flowers with a purple flash at the flower centre. Plant in full sun. Average, well-drained soil. Height: 15-20 cm (6-8 inches), Spread 30-45 cm (12-18 inches). USDA zones:3-9.
Phlox subulata 'Crimson Beauty' rose-pink flowers with a magenta flash at the flower centre. Plant in full sun. Average, well-drained soil. Height: 10-15 cm (4-6 inches), Spread 30-45 cm (12-18 inches). USDA zones:3-9.
Phlox subulata 'Emerald Blue' soft lavender colored flowers with a purple flash at the flower centre. Plant in full sun. Average, well-drained soil. Height: 15-20 cm (4-6 inches), Spread 30-60 cm (12-24 inches). USDA zones:3-9.
Phlox subulata 'White Delight' has large white star-shaped flowers in April or May. Full sun. Average, well-drained soil. Height: 15-20 cm (6-8 inches), Spread: 30-60 cm (12-24 inches). USDA zones:3-9.
Other white cultivars: 'Cotton Candy', 'Early White', 'Spring white'
Phlox subulata 'Candy Stripe' has masses of white flowers with a hot pink down the centre of the petal. Full sun. Average, well-drained soil. Height: 20 cm (8 inches), Spread 30-45 cm (12-18 inches). USDA zones:3-9.
Several types of Moss Phlox in the private garden of Marion Jarvie.
Companion Planting
Moss Phlox is most often used in rockeries where it fits in well with other alpine and rock garden plants.
Its low carpet of blooms also makes a great understory for daffodils and tulips. It can also look terrific planted alongside early flowering hellebores.
Plant type: Perennial
Height: 4-8 inches (10-20 cm)
Spread: 12-24 inches (30-60 cm)
Flower: Star-shaped flowers in a variety of colors
Bloom period: Early spring
Leaf: Green, needle-like foliage
Light: Full sun
Soil: Average, but must be well-drained
Moisture conditions: Prefers evenly moist, but free-drained soil
Divide: In spring after flowering
Deer Resistant: Somewhat deer resistant, but rabbits will eat this plant
Problems: Leaf miners, mites and caterpillars can be an issue. Other issues include rust, mildew, blight and stem canker
USDA Zones: 3-9
