Creeping phlox 'Emerald Blue'
Phlox subulata 'Emerald Blue' · Polemoniaceae Popular
A dense, needle-leaved, evergreen mat that disappears in spring under a sheet of lavender-blue flowers.
- Size
- 5 in tall, 24 in wide
- Zones
- 3 to 9
- Light
- Full sun
- Flowers
- Mid April to mid May
- Pets
- No toxicity recorded
- Job in a bed
- Carpet
A bed built around creeping phlox 'Emerald Blue'
The planner designed this bed around creeping phlox 'Emerald Blue' when this page was made: a 12 × 6 ft (3.7 × 1.8 m) English border in zone 6, full sun. It chose the other plants from the 966 that suit those conditions, and says below why creeping phlox 'Emerald Blue' stands where it does.
The plants
- 1 Creeping phlox 'Emerald Blue' × 7, blue
- 2 Bloody cranesbill × 3, pink
- 3 Brown-eyed Susan × 3, yellow
- 4 Switchgrass 'Cheyenne Sky' × 8, purple
- 5 Globe arborvitae 'Danica' × 1, green leaves
- 6 Ornamental onion 'Purple Sensation' × 4, purple
- 7 Spring starflower × 12, white
Why this plant
- The only blue.
Why here
- On the front edge. At 5 in it frames the bed without hiding it, and it is in leaf all season. It finishes 52% of the edge.
- 7 plants in 2 runs (4 and 3). Runs of different lengths make the edge a frame, not a ruled line.
Why now
- In flower for five weeks. From mid April to mid May.
- Fills a gap. For one of those weeks nothing else on the plan is in flower.
- One of two evergreens. They are what the bed has to show from November to March.
Planned as an English border: 4 of the 5 groups (80%) are drifts, longer along the bed than they are deep. Cool colours (blue, pink and purple) with yellow as the warm note, and white to calm things between them. The front edge is finished with bloody cranesbill and creeping phlox 'Emerald Blue'.
The planner's own design check: 12 Excellent, 5 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 creeping phlox 'Emerald Blue' goes in a border
At 5 in it belongs at the front of a bed. In the planner's ten height classes it is ground-hugging (up to 6 in).
Its job: carpet. A groundcover planted in threes and fives to cover the soil: along the front, and just behind it.
The most widely planted creeping phlox. Let it pour over a wall or bank. Shear it by half after flowering to keep the mat tight.
- Spilling over walls and banks
- Spring colour with bulbs
- Evergreen edging
What to plant with creeping phlox 'Emerald Blue'
Plants recorded as good partners for it, and what each pairing does:
- Candytuft: in flower together for five weeks, from mid April; tall enough (10 in) to stand behind it.
- Basket-of-gold: blue against yellow, opposite each other on the colour wheel, in flower together for five weeks; tall enough (10 in) to stand behind it.
- Tulip: blue against orange, opposite each other on the colour wheel, if you choose those colours, in flower together for four weeks; tall enough (18 in) to stand behind it.
Questions about creeping phlox 'Emerald Blue'
Does creeping phlox 'Emerald Blue' need sun or shade?
Creeping phlox 'Emerald Blue' grows in full sun (6 or more hours of direct sun a day).
It wants ordinary well-drained soil, of average fertility, and little watering once settled. Once settled in, it stands drought.
What zones does creeping phlox 'Emerald Blue' grow in?
USDA zones 3 to 9. It is hardy to zone 3, which means it survives winter nights down to about −30 °F (−34 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does creeping phlox 'Emerald Blue' flower in my zone?
In zone 5 it flowers mid April to mid 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 late May |
|---|---|
| Zone 4 | Late April to late May |
| Zone 5 | Mid April to mid May |
| Zone 6 | Mid April to early May |
| Zone 7 | Early April to early May |
| Zone 8 | Late March to late April |
| Zone 9 | Late March to mid April |
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 creeping phlox 'Emerald Blue' be planted?
18 in (45 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 24 in (60 cm), so a group knits into one patch.
It grows 5 in (12 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many creeping phlox 'Emerald Blue' plants do I need?
At 18 in apart, set out in staggered rows:
- 5 to fill 10 square feet (about 1 m²)
- 7 for a single row 10 ft (3 m) long
- 17 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as threes and fives, along the front and just behind it.
In the bed above, the planner used seven in two groups.
Is creeping phlox 'Emerald Blue' poisonous to dogs and cats?
No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension and the ASPCA.
"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.
Do deer eat creeping phlox 'Emerald Blue'?
Mostly not. NC State lists it as resistant to deer. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.
What flowers after creeping phlox 'Emerald Blue'?
Creeping phlox 'Emerald Blue' is over by mid May. These start as it finishes and carry the same spot on, so it never goes flat:
- Creeping thyme: from early June to mid July, 3 in tall, to stand in front of it and cover its fading stems.
- Lady's mantle: from late May to early July, 18 in tall.
- Catmint 'Walker's Low': from mid May to mid September, 24 in tall.
What does creeping phlox 'Emerald Blue' look like in winter?
Creeping phlox 'Emerald Blue' keeps its green leaves all winter, so it is one of the plants that hold a bed together from November to March, when the perennials have gone.
Is creeping phlox 'Emerald Blue' good for bees and butterflies?
Creeping phlox 'Emerald Blue' is visited by pollinators, bees, butterflies and hummingbirds.
It is native to the United States and Canada (this is a named variety of the native plant).
More Phlox
- Creeping phlox Phlox subulata
- Creeping phlox 'Candy Stripe' Phlox subulata 'Candy Stripe'
- 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 Phlox divaricata
- Woodland phlox 'Blue Moon' Phlox divaricata 'Blue Moon'
In these guides
- Salt-tolerant plants for roadsides and coasts
- Plants for slopes and banks
- Deer-resistant perennials for full sun
- Drought-tolerant perennials for full sun
- Pet-safe plants for a sunny border
- Native perennials for pollinators
- Garden plants native to Canada
- Plants for hummingbirds
- Plants for butterflies
- Plants for bees
- Low plants for the front of a border
- Groundcover plants
- Evergreen perennials, ferns and grasses
- Plants with blue flowers
Zone guides: Zone 3 · Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8 · Zone 9
Every fact on record
- Type
- Perennial (groundcover)
- Size
- 5 in (12 cm) tall, 24 in (60 cm) wide
- Plant
- 18 in (45 cm) apart
- Height class
- Ground-hugging (up to 6 in)
- Place in the bed
- Front
- Flowers
- Mid April to mid May; open bowls; blue, lavender
- Leaves
- Fine texture, evergreen; green
- Shape
- Mat-forming, spreading
- Hardy in
- USDA zones 3 to 9
- Light
- Full sun
- Soil
- Average, well-drained
- Water
- Low
- Feeding
- None needed
- Family
- Polemoniaceae
- Comes from
- Central and Eastern Canada and Central and Eastern United States
- Attracts
- Pollinators, bees, butterflies, hummingbirds
- Stands up to
- Deer, drought, salt, poor soil, pollution, erosion
Checked against NC State Extension, ASPCA poison lists 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.