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Garden phlox 'David'

Phlox paniculata 'David' · Polemoniaceae Popular

Garden phlox 'David' (Phlox paniculata 'David') in flower
Photo: Hardyplants, via Wikimedia Commons (CC0)

Large, domed heads of pure white, scented flowers on tall stems, with foliage that resists the mildew which spoils most phlox.

Size
3½ ft tall, 24 in wide
Zones
4 to 8
Light
Full sun to part sun
Flowers
Mid July to early September
Pets
No toxicity recorded
Job in a bed
Drift

A bed built around garden phlox 'David'

The planner designed this bed around garden phlox 'David' 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 garden phlox 'David' stands where it does.

A 12 × 6 ft (3.7 × 1.8 m) bed at eye level in early August: Garden phlox 'David', Blue moor grass, Stemless gentian, Joe-Pye weed 'Baby Joe', Globe arborvitae 'Danica', Pincushion flower 'Butterfly Blue', Snowdrop.
A 12 × 6 ft (3.7 × 1.8 m) English border in zone 6, full sun, seen from the path in early August.
1. Garden phlox 'David'11. Garden phlox 'David'11. Garden phlox 'David'14. Joe-Pye weed 'Baby Joe'44. Joe-Pye weed 'Baby Joe'44. Joe-Pye weed 'Baby Joe'45. Globe arborvitae 'Danica'52. Blue moor grass22. Blue moor grass22. Blue moor grass23. Stemless gentian33. Stemless gentian33. Stemless gentian32. Blue moor grass22. Blue moor grass22. Blue moor grass22. Blue moor grass22. Blue moor grass23. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian36. Pincushion flower 'Butterfly Blue'66. Pincushion flower 'Butterfly Blue'66. Pincushion flower 'Butterfly Blue'63. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian33. Stemless gentian37. Snowdrop7. Snowdrop7. Snowdrop7. Snowdrop7. Snowdrop7. Snowdrop7. Snowdrop7. Snowdrop7. Snowdrop7. Snowdrop7. Snowdrop7. Snowdrop
From above, to scale. Each circle is one plant, as wide as the room it needs.

The plants

  1. 2 Blue moor grass × 8, purple
  2. 3 Stemless gentian × 29, blue
  3. 4 Joe-Pye weed 'Baby Joe' × 3, pink
  4. 5 Globe arborvitae 'Danica' × 1, green leaves
  5. 6 Pincushion flower 'Butterfly Blue' × 3, lavender
  6. 7 Snowdrop × 12, white

Why this plant

  • Nothing here is unique to it. Its leaf, flower shape and colour are all on the plan already. Its case rests on where it stands and when it performs.

Why here

  • Anchors a back corner. At 3½ ft it is the tallest plant here, and the tallest close the ends of the bed, where they stand in front of nothing.
  • A step in the back row. Next to pincushion flower 'Butterfly Blue' (16 in): no two neighbours there are the same height, so the back steps up and down like a skyline.
  • 3 plants in one group. Massed, one kind reads as a single shape. Scattered, it would look spotty.

Why now

  • In flower for 9 weeks. From mid July to early September.
  • Part of the bed's peak. With joe-Pye weed 'Baby Joe' and pincushion flower 'Butterfly Blue' in late July: 3 kinds at once. No week has more.

Planned as an English border: 6 of the 6 groups (100%) are drifts, longer along the bed than they are deep. The longest in flower is pincushion flower 'Butterfly Blue': 21 weeks, from mid May to early October. Stemless gentian is planted in 7 places along the bed, which gives it rhythm.

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 garden phlox 'David' goes in a border

At 3½ ft it belongs at the back of a bed. In the planner's ten height classes it is moderately tall (3 to 4 ft).

Its job: drift. Planted in a small group of three or five, and repeated further along in the other number.

The white phlox to plant. It flowers for six weeks, longer if deadheaded, and its scent carries on warm evenings. Perennial Plant of the Year in 2002.

  • White for midsummer
  • Evening scent
  • The back of a border

What to plant with garden phlox 'David'

Plants recorded as good partners for it, and what each pairing does:

Questions about garden phlox 'David'

Does garden phlox 'David' need sun or shade?

Garden phlox 'David' grows in full sun (6 or more hours of direct sun a day) and part sun (4 to 6 hours of sun, including some afternoon sun).

It wants soil that stays evenly moist, rich in organic matter, and a good soak in dry spells.

What zones does garden phlox 'David' grow in?

USDA zones 4 to 8. It is hardy to zone 4, which means it survives winter nights down to about −20 °F (−29 °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 garden phlox 'David' flower in my zone?

In zone 5 it flowers mid July to early September. As a summer flower it moves about half a week for every zone: earlier where it is warmer.

Roughly when garden phlox 'David' is in flower
Zone 4Mid July to early September
Zone 5Mid July to early September
Zone 6Mid July to early September
Zone 7Early July to early September
Zone 8Early July to early September

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 garden phlox 'David' be planted?

20 in (50 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 3½ ft (110 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.

How many garden phlox 'David' plants do I need?

At 20 in apart, set out in staggered rows:

  • 4 to fill 10 square feet (about 1 m²)
  • 7 for a single row 10 ft (3 m) long
  • 14 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 three in one group.

Is garden phlox 'David' 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 garden phlox 'David'?

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 garden phlox 'David'?

Garden phlox 'David' is over by early September. These start as it finishes and carry the same spot on, so it never goes flat:

  • Garden chrysanthemum: from mid September to late October, 24 in tall, to stand in front of it and cover its fading stems.
  • Blue mistflower: from late August to mid October, 2½ ft tall, to stand in front of it and cover its fading stems.
  • Blue wood aster: from mid September to mid October, 3 ft tall.

What does garden phlox 'David' look like in winter?

Garden phlox 'David' dies down to the ground and there is nothing to see until spring. The old stems can be cut in autumn, or left until spring as shelter for overwintering insects.

Is garden phlox 'David' good for bees and butterflies?

Garden phlox 'David' is visited by pollinators, bees, butterflies and hummingbirds.

It is native to the United States (this is a named variety of the native plant).

More Phlox

In these guides

Zone guides: Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8

In flower in: July · August · September

Every fact on record

Type
Perennial
Size
3½ ft (110 cm) tall, 24 in (60 cm) wide
Plant
20 in (50 cm) apart
Height class
Moderately tall (3 to 4 ft)
Place in the bed
Back
Flowers
Mid July to early September; dense clusters; white
Leaves
Medium texture, herbaceous; green
Shape
Upright, clumping
Hardy in
USDA zones 4 to 8
Light
Full sun, part sun
Soil
Rich, evenly moist
Water
Moderate
Feeding
Moderate, in spring
Family
Polemoniaceae
Comes from
Eastern United States
Attracts
Pollinators, bees, butterflies, hummingbirds
Stands up to
Black walnut

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.