BattenBlooms
PL. —Phlox paniculataBotanical illustration — drop image
Phlox paniculata

Garden Phlox

Summer
4a–8bHardiness zone
Peak bloom windowZone 6b · frost-offset weeks
Winter
Not in bloom
Spring
In bloom
Summer
Peak bloom
Fall
Not in bloom
Peak bloom
In bloom
Background

Garden phlox fills the midsummer garden with large, domed clusters of fragrant flowers in shades of pink, red, white, lavender, and bicolors. The scent — sweet, slightly spicy — carries well and makes it one of the most rewarding cut flowers of high summer. It is reliably perennial in Zone 4–8 and spreads steadily, responding well to division every 2–3 years.

Powdery mildew is the main challenge; choose resistant varieties (most modern cultivars have significantly improved resistance) and plant with adequate spacing for air circulation. Cut when about a quarter of the flowers in the cluster are open — the remaining buds will open over 5–7 days in the vase.

Good companions
Monarda didymaEchinacea purpurea
Care guide
SunFull sun to light shade
WaterRegular; consistent moisture for best performance
SoilRich, moist, well-draining
Spacing18–24 inches
Height3–4 feet
Zone4a – 8b
Native RegionAL, AR, CT, DC, DE, FL, GA, IL, IN, KS, KY, LA, MA, MD, MI, MO, MS, NC, NH, NJ, NY, OH, OK, PA, RI, SC, TN, TX, VA, VT, WI, WV
Frost hardy
Seasonal tasks
spring
cutDivide clumps every 2–3 years in spring to maintain vigour and control size
summer
cutCut when a quarter of cluster flowers are open — buds continue opening in the vase
watchPowdery mildew on lower leaves is common — choose resistant varieties and space well
Common problems

Powdery mildew

Symptoms

White or grey powdery coating on leaves — usually starting on older growth in humid conditions or when nights cool.

Treatment

Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.