Illustration
David
Phlox paniculata 'David'
Also called tall garden phlox
David blooms from July through September.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing David
Plant it in full sun. It prefers moderate water. It is hardy in USDA zones 4–8. Expect it to reach about 3.5 ft tall and 2 ft wide at maturity, in roughly 2 years (not yet checked).
No toxicity note is on file for David. That is not a clearance: check its safety for people and pets before planting.
What was checked
Mature height and spread, hardiness zones, sun and the trait tags were checked against named botanical sources for this plant. The bloom months and water need on this page were not, and each fact above says which. The planting, spacing and size sections are derived from these checked facts by a fixed rule, not checked separately, and the plant type is the library's own classification.
When to plant David
Plant David in early spring as soon as the soil is workable, or in early fall at least six weeks before your first frost, so roots establish in cool weather. In zone 6, the middle of its hardy zones 4 to 8, spring means March to May and fall means August or September. Once settled, it blooms from July to September.
Month-by-month timing for your zone is on the planting calendar; if you garden near zone 6, the middle of this plant's hardy range, start with zone 6 in March. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does David get?
3.5 fttall5 ft 7 inan adult2 ftwideSee David in a garden plan: the planner shows it in 3D beside everything else you add, growing toward this size over the years.
How far apart to plant David
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space David about 2 ft apart, center to center, so each plant has room to reach its full width.
Add David to a garden plan and the planner draws it at its full width, so you see the spacing before you buy.
Where these facts come from
David's height, spread, hardiness zones, sun and trait tags were checked against 12 published sources on August 1, 2026. Each one is linked below with every fact it carried, which can include a fact this page still marks as not yet checked, because a source carrying a value is not the same as the value being held to the standard. Facts not in that list, and the planting, spacing and size sections, are not covered by these sources.
- NC State ExtensionPlant Toolboxheight, spread, hardiness zones, sun, years to mature size and trait tags
- gilberthwild.comGilbert H. Wild & Sonheight, spread, hardiness zones, sun and trait tags
- High Country Gardensheight, spread, hardiness zones, sun and trait tags
- Missouri Botanical GardenPlant Finderheight, spread, hardiness zones, sun and trait tags
- Clemson Home and Garden Information CenterClemson Cooperative Extension Home & Garden Information Centerheight, sun, years to mature size and trait tags
- Plant Delights Nurseryheight, hardiness zones, sun and trait tags
- RHSRoyal Horticultural Societyheight, spread, sun and trait tags
- Mt. Cuba CenterPhlox for Sun trialheight, spread and trait tags
- University of Illinois ExtensionHort Answersheight, hardiness zones and sun
- Penn State Extensionhardiness zones and sun
- University of Illinois ExtensionFlowershardiness zones and sun
- University of Minnesota Extensionsun and trait tags
How the checking works, and what each standard covers, is on the verified plants page.
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Design a garden with this
Drop this plant onto a 3D plan, see how it fills in, and watch your whole garden bloom across the year.