Phlox

Frilly simple-petaled flowers with white and purple stripes

Intensia® 'Star Brite' phlox in UF's Fifield Garden.

Roadside stands of wild phlox blend in with the grass most of the year, but in late winter and spring these plants burst forth with color. The flowers are a favorite of both pollinators and gardeners. Although they are now less common in nurseries, phlox is still worth adding to your garden and perhaps passing along to a friend.

Characteristics

Depending on the species, phlox foliage can be oblong to linear in shape. The leaves are relatively lackluster, but the flowers truly are a show. The small blooms appear singularly or in clusters that are held loftily above the plant. Many colors are available, and some cultivars are even bicolored. There are three main varieties: annual phlox, garden phlox, and creeping phlox. Annual and creeping phlox are native to North America, while garden phlox is native to the Eastern US. Phlox thrives in North Florida and can grow as far south as zone 10.

Annual phlox (Phlox drummondii) tends to reach heights of six inches to a foot and a half tall, with sweet-smelling flowers that come in shades of red, lavender, and white. Choose this species if you intend to use the plant as a groundcover, edging, or in a container. Garden phlox (Phlox paniculata) gets a bit taller, reaching three to five feet. The clusters of magenta blooms are quite showy and proliferate through the summer.

Creeping phlox plants covered in small pale lavender flowers growing on and over a garden wall

Creeping phlox provides a cascade of blooms over the edge of containers or walls.

Creeping phlox (Phlox subulata) can typically be found in big box stores. They can be up to a foot tall and are ideal as a groundcover or cascading plant. They also can help stabilize sloping landscapes. Cultivars include 'Crimson Beauty' (red flowers), 'Emerald Cushion' (pink flowers), 'Millstream' (white flowers with a crimson eye), 'Millstream Daphne' (dark blue flowers), and 'White Delight' (white flowers). These are all cultivated varieties, but wild phlox also comes in a number of colors.

Planting and Care

If you live in a colder part of the state, plant phlox during the spring. Plant phlox in the fall if freezes are rare where you live, or if you want to grow it from seed. Choose a planting location with full sun or partial shade, and soil that is rich but well drained. Just expect fewer flowers in shady areas. Phlox can tolerate some drought but will decline in areas that are consistently wet.

Supplemental irrigation is only necessary if a dry spell occurs during the growing season. Plants will also benefit from the application of a general-use fertilizer in the spring once they awaken from winter dormancy. Remove spent blossoms to achieve the most blooming. Since phlox typically reseeds on its own, you'll likely only need to plant it once.

The main issues to scout for with phlox are powdery mildew and crown rot. Both can be avoided by keeping foliage as dry as possible. Other less common issues include mites and leaf spots.

A bed of phlox with small purple flowers in round clusters atop a single stem

The blooms of garden phlox are perfect for cut flowers.

Phlox produces excellent flowers for cutting since they're colorful, pleasantly scented, and held on long stems. Phlox also makes a great passalong plant, especially since the old-garden varieties are hard to find. Propagate by division in the early spring or from stem cuttings in the summer and fall.

Don't worry if you have any questions as you add phlox to your garden. The experts at your county Extension office are available and happy to advise.

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