Garden phlox Phlox paniculata
Garden phlox (Phlox paniculata) is a deciduous perennial flowering plant in the Polemoniaceae family, native to Eastern and central United States. It grows 60 cm–1.2 m (24 in–3.9 ft) tall and 50–90 cm (20–35 in) wide, wants full sun and moderate water, and is hardy to about -34 °C (-29 °F). Space plants about 60 cm (24 in) apart.
Plan Garden phlox in your garden →
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Garden phlox at a glance
| Type | Perennial flowering plant, deciduous |
|---|---|
| Family | Polemoniaceae |
| Mature height | 60 cm–1.2 m (24 in–3.9 ft) |
| Mature spread | 50–90 cm (20–35 in) |
| Spacing | 60 cm (24 in) centre to centre |
| Sun | Full sun, at least 6 h of direct sun a day |
| Water | Moderate; drought tolerance low, waterlogging tolerance low |
| Soil pH | 6–7.5 |
| Cold hardiness | About -34 °C (-29 °F) once established (roughly USDA zone 4) |
| Heat stress | Likely above about 30 °C (86 °F) |
| Flowering | from about July for 6–9 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 |
| Common in gardens of | 🇺🇸 United States, 🇬🇧 United Kingdom, 🇩🇪 Germany, 🇷🇺 Russia |
Is Garden phlox toxic?
- People: not known to be toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
Not listed as toxic by ASPCA; no significant toxicity reported for Phlox.
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 Garden phlox
No well-documented helpful pairing. Group it with plants that like full sun and moderate water.
Keep apart or take care
- caution With Bee balm: Both garden phlox and bee balm are very prone to powdery mildew; planting them together in a humid, crowded spot raises disease pressure, so give them good air circulation. Evidence B
Questions about Garden phlox
- How far apart should I plant Garden phlox?
- About 60 cm (24 in) apart, centre to centre. A mature plant spreads 50–90 cm (20–35 in).
- Does Garden phlox need full sun?
- Full sun: at least 6 hours of direct sun a day.
- How much water does Garden phlox need?
- Moderate water. Drought tolerance is low and waterlogging tolerance low.
- How cold-hardy is Garden phlox?
- It tolerates about -34 °C (-29 °F) once established, roughly USDA zone 4.
- When does Garden phlox flower?
- From about July for 6–9 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Garden 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. Not listed as toxic by ASPCA; no significant toxicity reported for Phlox.
- What grows well with Garden phlox?
- There is no well-documented companion pairing for Garden phlox. Group it with plants that like the same sun (full sun) and water (moderate).
Sources and evidence
Evidence grade B (B: extension service or peer-reviewed).
- Missouri Botanical Garden Plant Finder, Missouri Botanical Garden
- RHS Plant Finder, Royal Horticultural Society
- University extension gardening guides (general), Various land-grant university extensions
- ASPCA Toxic and Non-Toxic Plant List, ASPCA
Notes and assumptions
- Typical garden-form values; cultivars and local conditions differ.
- Prone to powdery mildew in humid, crowded sites; good airflow and mildew-resistant cultivars help.
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
- Moss phlox (creeping phlox) Phlox subulata
- 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
- Sunflower Helianthus annuus
- French marigold Tagetes patula
- English lavender Lavandula angustifolia