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longleaf phlox

Phlox longifolia · Polemoniaceae

longleaf phlox (Phlox longifolia)
Photo: (c) Daughter Dad, some rights reserved (CC BY) · CC BY · via iNaturalist

longleaf phlox (Phlox longifolia) is a perennial herbaceous plant in the Polemoniaceae family. It is native to North America. USDA records it as hardy in zone 5 and warmer, down to about -13°F.

At a glance

Typeforb-herb Derived
Lifecycleperennial USDA
Native statusnative USDA
Mature height1.2 ft USDA
Lightpart-shade USDA
Water needlow USDA
Growth rateslow USDA
Soil pH6.5–8.5 USDA
BloomMay–June USDA
Flower colorPurple USDA
Hardiness zones5 and warmer USDA
Guild layerground-cover Derived
Nursery availabilityNo Known Source USDA

USDA quoted from the USDA PLANTS database · Derived computed by a fixed rule from those columns. No value on this page is estimated.

Growing conditions

It grows in partial shade. USDA rates it as having low water needs once established. Its drought tolerance is rated high. It will not tolerate waterlogged soil — USDA rates its anaerobic tolerance as none. It is recorded on soils from pH 6.5 to 8.5 — a broad range that spans acidic through mildly alkaline ground. Its cold limit is zone 5.

Size and growth

At maturity it reaches about 1.2 ft, making it a low, mat-forming plant. It grows slowly.

Bloom period

USDA records a bloom period of May through June. Flowers are purple.

A flowering date, not a pollinator rating.

Foliage, flower and season

Summer foliage is green, coarse in texture. Its flowers are conspicuous. Its active growth period is spring and summer. USDA rates its lifespan as long.

What the site needs to provide

USDA records it across sites receiving 20 to 40 inches of annual precipitation. It needs at least 120 frost-free days to finish its season. It roots to at least 15 inches. Fertility requirement: low — no feeding needed on ordinary garden soil.

Propagating it

Propagate it from seed, bare root and container stock. Seed needs cold stratification — a period of moist chilling — before it will germinate, so sow in autumn or chill it artificially before a spring sowing. Its seed spreads at a slow rate. It does not spread vegetatively, so it will stay where you put it.

Resilience and wildlife

Browsing animals find it moderately palatable, so expect deer and rabbits to take an interest. Its fire tolerance is rated medium. Its growth form is recorded as multiple stem.

Role in a guild

Ground cover. In a layered planting this is the lowest layer — it shades soil, holds moisture, and suppresses weeds. The layer is derived by a fixed rule from growth habit and mature height.

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Tags

deciduousdrought-tolerantsandy-soilnativeslow-growingground-cover

Related plants

Others in Phlox

Similar role and hardiness

Where this data comes from

Every value on this page comes from the USDA PLANTS database record for symbol PHLO2, or is computed from those values by a fixed rule. Nothing here is estimated or model-generated. Where USDA publishes no value, this page omits the claim rather than filling the gap.

Read our full data sources and methodology.

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