Garden Phlox
Phlox paniculata
Garden Phlox blooms from July through September.
Mature size, hardiness zones, sun and the trait tags were checked against named botanical sources for this plant. The bloom months and water need on this page were not.
Growing Garden Phlox
Plant it in full sun. It prefers moderate water. It is hardy in USDA zones 4–8. Expect it to reach about 3.3 ft tall and 2 ft wide at maturity, in roughly 2 years.
When to plant Garden Phlox
Plant Garden Phlox in early spring as soon as the soil is workable, or in early fall at least six weeks before your first frost, so roots establish in cool weather. For the middle of its hardy zones 4 to 8 range, spring means March to May and fall means August or September. Once settled, it blooms from July to September.
Month-by-month timing for your zone is on the planting calendar: for the middle of its range, start with zone 6 in March.
Comes in 12 varieties across 5 colors
Same plant, same care - pick the color you are growing.
Good to know about Garden Phlox
Curated from university extensions, botanic gardens and other primary sources, with the source named on every note.
Worth knowing
Water is not the way to fight powdery mildew: free water on the leaf actually kills the spores. The fixes are about light and air: full sun, spacing, airflow. per UC ANR
When it stops blooming
Sources split on the end date. The natural flush is July to August; reaching September depends on regular deadheading and summer heat that stays moderate. per North Carolina Extension and Penn State
Resistant cultivars matter most
Cultivar choice is the biggest lever against powdery mildew. 'David' (white), 'Jeana' (lavender-pink) and 'Robert Poore' (rosy-red) are the widely recommended mildew-resistant selections. per Clemson and Mt. Cuba
Seedlings revert to magenta
Left to set seed, named phlox reverts: the seedlings come up a washy pale magenta and can crowd out and swamp your chosen cultivar. Deadhead to prevent it. per University of Minnesota and Penn State
A butterfly magnet
A strong butterfly and hummingbird plant. In a Mt. Cuba trial, 'Jeana' drew far more butterflies than any other cultivar, at 539 recorded visits over two years. per North Carolina Extension and Mt. Cuba
Not deer-resistant
Unlike low creeping phlox, garden phlox is not deer-resistant, and cottontail rabbits will browse it. Site it where deer and rabbit pressure is low. per North Carolina Extension
What pairs well with Garden Phlox
Good companions share its growing conditions and add something it lacks: an earlier or later bloom, a lower carpet in front, or structure through winter.
Sea Thrift
Shares full sun and low to moderate water; blooms in mid spring, before this one opens; lower at 8 in, for the front of the border; both offer pollinator forage, in different months.
English Daisy
Shares full sun and moderate water; blooms in mid spring, before this one opens; low at 6 in, to carpet the ground beneath; both offer pollinator forage, in different months.
Aster
Shares full sun and moderate water; overlaps, then carries the display into mid fall; both are strong pollinator plants; its seed heads stand through winter, for structure and the birds.
Chives
Shares full sun and moderate water; blooms in late spring, before this one opens; both are strong pollinator plants, and they feed in different months; lower at 12 in, for the front of the border.
Pansy
Takes full sun to part sun and moderate water; blooms in early spring, before this one opens; lower at 8 in, for the front of the border; both offer pollinator forage, in different months.
Thyme
Shares full sun and low to moderate water; opens in late spring and overlaps into this one's season; low at 6 in, to carpet the ground beneath; both are strong pollinator plants.
African Daisy
Shares full sun and moderate water; blooms in mid spring, before this one opens; both offer pollinator forage, in different months; lower at 12 in, for the front of the border.
Stock
Shares full sun and moderate water; blooms in mid spring, before this one opens; both offer pollinator forage, in different months; lower at 1.6 ft, for the front of the border.
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