How to Grow Phlox: The Complete Phlox Flower Guide

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Phlox
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Planting, Growing, and Caring for Phlox Flowers

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If you spot low-growing blankets of flowers in bright pink in springtime, it’s often Creeping Phlox! But there are medium and tall varieties of phlox as well, which grow in late spring and summer; these perennials are the cornerstone of many perennial flower beds. Learn all about growing phlox.

About Phlox

“Phlox is a genus with a great diversity in growth form, with a height varying between 3 to 6 inches for Phlox subulata to 5 feet tall for Phlox. paniculata. They may grow in a low, mounding form, a spreading woodland phlox or tall, upright phlox,” explains the North Carolina Cooperative Extension.

These perennials sport copious star-shaped, colorful flowers from spring through summer, depending on the variety. Because there are so many types (many of which are native to North America), you can find a phlox for almost any garden. Truly, their versatility can’t be overstated. 

  • Low-growing Creeping Phlox works great as ground cover in sunny yards.
  • Ankle-high Woodland Phlox is perfect for dappled, shady beds.
  • Medium-height Garden Phlox is often the ‘backbone’ of the perennial garden, providing a layer of color midway through the garden and filling in gaps.
  • Tall Garden Phlox are excellent as a colorful backdrop with large flower clusters, and they are often fragrant. 

Bees, butterflies, and pollinators also belove Phlox. And fortunately, phlox is deer-resistant, as deer do NOT like smelly flowers!

Planting

Because there are so many different types of phlox, sunlight requirements vary. Tall garden phlox do best in full sun, while woodland species thrive in partial shade. (See Recommended Varieties, below, for more information!)

In general, phlox prefer soil that is nutrient rich and evenly moist. They do not like to sit in wet soil, however. Use a garden fork or tiller to prepare your garden bed prior to planting. Loosen the soil to about 12 to 15 inches deep, then mix in a 2- to 4-inch layer of compost to improve soil consistency and fertility.

When to Plant Phlox

How to Plant Phlox

  • It is easier to grow phlox from cuttings/transplants than from seeds, although established plants will readily spread by seed in the garden.
  • Space plants according to their mature size.
  • If you are transplanting a plant from a pot, dig a hole about twice the size of the pot’s diameter and place the plant so that the top of the root ball is even with the soil’s surface. Fill in around the root ball, and remember to water it thoroughly.

Phlox

Growing

  • If you receive less than 1 inch of rain a week, remember to regularly water your plants throughout the summer.
  • Each spring, put a thin layer of compost and a 2-inch layer of mulch around the plants to help keep the soil moist and control weeds.
  • Remember to remove the dead/faded flowers so that your plants can rebloom. Try out the Chelsea Chop!
  • If you have tall phlox, cut the stems back to about 1 to 2 inches above the soil after the first killing frost in the fall. (See local frost dates.) Divide tall garden phlox every 2 to 3 years to ensure healthy and disease-free plants.
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Wit and Wisdom

  • April’s full Moon has traditionally been called the “Full Pink Moon” because it heralded the appearance of the “moss pink,” or wild ground phlox—one of the first spring flowers.
  • Medium and tall phlox are good companions for summer perennials such as lilies, bee balm, rudbeckia, Shasta daisies, yarrow, and clematis.

 

Pests/Diseases

  • Powdery mildew is common; keep proper air circulation in mind when spacing out plants and avoid getting excess water on the foliage. Cutting back stems after flowering can also help to reduce the spread of powdery mildew, as can choosing mildew-resistant varieties.
  • Stem canker
  • Rust
  • Southern blight
  • Stem nematodes
  • Leaf spots
  • Leaf miners
  • Caterpillars
About The Author

Catherine Boeckmann

Catherine Boeckmann loves nature, stargazing, and gardening so it’s not surprising that she and The Old Farmer’s Almanac found each other. She leads digital content for the Almanac website, and is also a certified master gardener in the state of Indiana. Read More from Catherine Boeckmann