Woodland phlox
Phlox divaricata · Polemoniaceae
Loose clusters of fragrant, lavender-blue flowers float over the woodland floor in spring. It spreads gently into loose mats.
- Size
- 12 in tall, 12 in wide
- Zones
- 3 to 8
- Light
- Part sun to shade
- Flowers
- Late April to late May
- Pets
- No toxicity recorded
- Job in a bed
- Drift
A bed built around woodland phlox
The planner designed this bed around woodland phlox when this page was made: a 12 × 6 ft (3.7 × 1.8 m) naturalistic planting in zone 6, part shade. It chose the other plants from the 513 that suit those conditions, and says below why woodland phlox stands where it does.
The plants
- 1 Woodland phlox × 8, blue
- 2 Moor grass 'Greenlee' × 3, tan
- 3 Turtlehead 'Hot Lips' × 3, pink
- 4 Japanese meadowsweet × 3, pink
- 5 Inkberry 'Gem Box' × 1, dark green leaves
- 6 Golden ragwort × 17, yellow
- 7 Yellow trout lily × 12, yellow
- 8 Winter cyclamen × 5, white
Why this plant
- The only dense clusters. The others are spires, plumes, daisies and others. Shape reads at a distance, where colours blur.
- A classic partner for golden ragwort. Both are on this plan. A pairing gardeners have proved outranks a general rule.
- The only blue.
Why here
- On the front edge. At 12 in it frames the bed without hiding it, and it is in leaf all season. It finishes 62% of the edge.
- 8 plants in 2 runs (5 and 3). Runs of different lengths make the edge a frame, not a ruled line.
- Beside golden ragwort. A recognised partner: the planner puts such plants together where it can.
Why now
- In flower for five weeks. From late April to late May.
- Part of the bed's peak. With golden ragwort and yellow trout lily in late April: 3 kinds at once. No week has more.
Planned as a naturalistic planting: low grasses and groundcovers, the matrix, make up 42% of the planted ground. The longest in flower is moor grass 'Greenlee': 15 weeks, from mid May to late August. The bed is tied together by its repeats: two kinds come round again along it, golden ragwort and woodland phlox.
The planner's own design check: 11 Excellent, 6 Good. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where woodland phlox goes in a border
At 12 in it belongs at the front of a bed. In the planner's ten height classes it is low (6 to 12 in).
Its job: drift. Planted in a small group of three or five, and repeated further along in the other number.
The best blue for the spring woodland, flowering with tulips, foamflower and wild geranium. Shear it after flowering to keep it dense.
- Blue under deciduous trees in spring
- Native woodland gardens
- Planting with spring bulbs
What to plant with woodland phlox
Plants recorded as good partners for it, and what each pairing does:
- Foamflower: in flower together for five weeks, from late April; spires rising out of its mound; happy in the same moist soil.
- Virginia bluebells: in flower together for three weeks, from late April; tall enough (20 in) to stand behind it; happy in the same moist soil.
- Christmas fern: its dark green leaves are a setting for the flowers, before and after; tall enough (20 in) to stand behind it.
Questions about woodland phlox
Does woodland phlox need sun or shade?
Woodland phlox grows in part sun (4 to 6 hours of sun, including some afternoon sun), part shade (2 to 4 hours of sun, mostly in the morning) and shade (less than 2 hours of direct sun, or bright dappled light).
It wants soil that stays evenly moist, rich in organic matter, and a good soak in dry spells. Once settled in, it stands drought.
What zones does woodland phlox grow in?
USDA zones 3 to 8. It is hardy to zone 3, which means it survives winter nights down to about −30 °F (−34 °C).
Above zone 8 it struggles: the zones measure winter cold, but a plant's top zone usually means the summers are too hot or the winters too mild for it to rest.
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does woodland phlox flower in my zone?
In zone 5 it flowers late April to late May. As a spring flower it moves about a week for every zone: earlier where it is warmer, later where it is colder.
| Zone 3 | Early May to early June |
|---|---|
| Zone 4 | Early May to late May |
| Zone 5 | Late April to late May |
| Zone 6 | Mid April to mid May |
| Zone 7 | Mid April to early May |
| Zone 8 | Early April to early May |
Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.
How far apart should woodland phlox be planted?
12 in (30 cm) apart, from the middle of one plant to the middle of the next. That is about its full width, so each plant keeps its own outline.
It grows 12 in (30 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many woodland phlox plants do I need?
At 12 in apart, set out in staggered rows:
- 12 to fill 10 square feet (about 1 m²)
- 11 for a single row 10 ft (3 m) long
- 38 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as a group of three or five, with a second group further along in the other number.
In the bed above, the planner used eight in two groups.
Is woodland phlox poisonous to dogs and cats?
No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension.
"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.
Do deer eat woodland phlox?
They may. NC State does not list it as resistant to deer or rabbits. Where they visit, protect it, or plant it among ones they avoid.
What flowers after woodland phlox?
Woodland phlox is over by late May. These start as it finishes and carry the same spot on, so it never goes flat:
- Lady's mantle: from late May to early July, 18 in tall.
- Astilbe: from late June to mid July, 24 in tall.
- Carpathian bellflower 'Blue Clips': from late June to late August, 8 in tall, to stand in front of it and cover its fading stems.
What does woodland phlox look like in winter?
Woodland phlox holds some of its leaves into winter, more in a mild year or a sheltered spot, and they look tired by March. Cut the old ones off as new growth starts.
Is woodland phlox good for bees and butterflies?
Woodland phlox is visited by bees, butterflies and hummingbirds.
It is native to the United States and Canada.
More Phlox
- Creeping phlox Phlox subulata
- Creeping phlox 'Candy Stripe' Phlox subulata 'Candy Stripe'
- Creeping phlox 'Emerald Blue' Phlox subulata 'Emerald Blue'
- Creeping phlox 'Sherwood Purple' Phlox stolonifera 'Sherwood Purple'
- Creeping woodland phlox Phlox stolonifera
- Garden phlox Phlox paniculata
- Garden phlox 'Bright Eyes' Phlox paniculata 'Bright Eyes'
- Garden phlox 'David' Phlox paniculata 'David'
- Garden phlox 'Jeana' Phlox paniculata 'Jeana'
- Garden phlox 'Laura' Phlox paniculata 'Laura'
- Woodland phlox 'Blue Moon' Phlox divaricata 'Blue Moon'
In these guides
- Plants for dry shade
- Pet-safe plants for shade
- Native perennials for pollinators
- Native plants for shade
- Garden plants native to Canada
- Plants for hummingbirds
- Plants for butterflies
- Plants for bees
- Low plants for the front of a border
- Plants with blue flowers
- Plants for a white garden
Zone guides: Zone 3 · Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8
Every fact on record
- Type
- Perennial
- Size
- 12 in (30 cm) tall, 12 in (30 cm) wide
- Plant
- 12 in (30 cm) apart
- Height class
- Low (6 to 12 in)
- Place in the bed
- Front
- Flowers
- Late April to late May; dense clusters; blue, lavender, white
- Leaves
- Medium texture, semi-evergreen; green
- Shape
- Mounding, spreading
- Hardy in
- USDA zones 3 to 8
- Light
- Part sun, part shade, shade
- Soil
- Rich, evenly moist
- Water
- Moderate
- Feeding
- Light, in spring
- Family
- Polemoniaceae
- Comes from
- Eastern North America
- Attracts
- Bees, butterflies, hummingbirds
- Stands up to
- Drought
Checked against NC State Extension and VASCAN (plants of Canada). Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.