Phlox alyssifolia subsp. collina
Phlox alyssifolia subsp. collina
Hill phlox is a low-growing Montana native that thrives in partially shaded rock gardens and borders with well-draining, moderately moist soil. Water regularly but avoid waterlogging, as this subspecies dislikes prolonged wet conditions. Deadhead spent flowers to encourage a longer blooming season and divide clumps every 2–3 years to maintain vigor.
Care Level
Moderate
Sun
Partial Shade
Water
Moderate
Growth Rate
Moderate
Mature Height
18″ – 36″
Soil
loam
Life Cycle
Perennial
Spacing
12″
Watering Schedule
Every 7-10 Days • Water Until Soil Is Evenly Moist, Then Allow Top Inch To Dry Before Watering Again
Soil pH
5.8 – 7.7
Temperature
-10° – 85°F
Mature Spread
up to 24″
Root Depth
Medium
Foliage
Coarse
Native to
Attracts
Sources
Data: trefle, usda
No nurseries currently have this species in stock.