Moss phlox (creeping phlox) Phlox subulata
Moss phlox (creeping phlox) (Phlox subulata) is an evergreen perennial groundcover in the Polemoniaceae family, native to Eastern and central United States (dry rocky slopes). It grows 10–15 cm (4–6 in) tall and 40–60 cm (16–24 in) wide, wants full sun and low water, and is hardy to about -37 °C (-35 °F). Space plants about 40 cm (16 in) apart.
Plan Moss phlox (creeping phlox) in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Moss phlox (creeping phlox) at a glance
| Type | Perennial groundcover, evergreen |
|---|---|
| Family | Polemoniaceae |
| Mature height | 10–15 cm (4–6 in) |
| Mature spread | 40–60 cm (16–24 in) |
| Spacing | 40 cm (16 in) centre to centre |
| Sun | Full sun, at least 6 h of direct sun a day |
| Water | Low; drought tolerance moderate, waterlogging tolerance none |
| Soil pH | 5.5–7 |
| Cold hardiness | About -37 °C (-35 °F) once established (roughly USDA zone 3) |
| Heat stress | Likely above about 32 °C (90 °F) |
| Flowering | from about April for 3–5 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Low |
| Pollinator value | High |
| Edible | Not grown as food |
| Native to | Eastern and central United States (dry rocky slopes) |
| Common in gardens of | 🇺🇸 United States, 🇯🇵 Japan |
Is Moss phlox (creeping phlox) toxic?
- People: not known to be toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
No toxicity reported in ASPCA or standard poison references.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Moss phlox (creeping phlox)
No well-documented helpful pairing. Group it with plants that like full sun and low water.
See Moss phlox (creeping phlox) in a botanical garden
It grows in these sample gardens, which you can walk through in 3D:
- Brooklyn Botanic Garden (10 plants)
- Arctic-Alpine Botanic Garden (20 plants)
- Denver Botanic Gardens (20 plants)
- New York Botanical Garden (24 plants)
- Kew: glasshouses and rock garden (5 plants)
Questions about Moss phlox (creeping phlox)
- How far apart should I plant Moss phlox (creeping phlox)?
- About 40 cm (16 in) apart, centre to centre. A mature plant spreads 40–60 cm (16–24 in).
- Does Moss phlox (creeping phlox) need full sun?
- Full sun: at least 6 hours of direct sun a day.
- How much water does Moss phlox (creeping phlox) need?
- Low water. Drought tolerance is moderate and waterlogging tolerance none.
- How cold-hardy is Moss phlox (creeping phlox)?
- It tolerates about -37 °C (-35 °F) once established, roughly USDA zone 3.
- When does Moss phlox (creeping phlox) flower?
- From about April for 3–5 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Moss phlox (creeping phlox) poisonous to cats and dogs?
- For cats it is not known to be toxic; for dogs not known to be toxic; for people not known to be toxic. No toxicity reported in ASPCA or standard poison references.
- What grows well with Moss phlox (creeping phlox)?
- There is no well-documented companion pairing for Moss phlox (creeping phlox). Group it with plants that like the same sun (full sun) and water (low).
Sources and evidence
Evidence grade B (B: extension service or peer-reviewed).
- Missouri Botanical Garden Plant Finder, Missouri Botanical Garden
- Extension Gardener Plant Toolbox, NC State Extension
- RHS Plant Finder, Royal Horticultural Society
Notes and assumptions
- Flower colour varies by cultivar from white and pink to lavender and red.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Garden phlox Phlox paniculata
- Qantu (sacred flower of the Incas) Cantua buxifolia
- Cup-and-saucer vine (cathedral bells) Cobaea scandens
- Woodland phlox (wild blue phlox) Phlox divaricata
- Creeping Jacob’s ladder (spreading Jacob’s ladder) Polemonium reptans
- Creeping thyme Thymus serpyllum
- Hosta Hosta spp.
- Lamb's ear Stachys byzantina