Illustration
Purple Annual Phlox
Phlox drummondii
Purple Annual Phlox blooms from May through September.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Purple Annual Phlox
Plant it in full sun. It prefers moderate water. It is hardy in USDA zones 2–11. Expect it to reach about 12 in tall and 12 in wide at maturity, in roughly 1 year (not yet checked).
No toxicity note is on file for Purple Annual Phlox. That is not a clearance: check its safety for people and pets before planting.
What was checked
Fifteen fields were checked against named botanical sources, each recorded beside the sources that carried it, with every unsettled point written down and decided: mature height and spread, hardiness zones, sun, water, bloom months and color, the trait tags, soil, diseases, pests, toxicity, the plant's own names, and years to mature size, which rests on a recorded house rule where no publisher states one and is marked so. Each fact above carries its own mark. 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 Purple Annual Phlox
Wait until all danger of frost has passed, then plant out Purple Annual Phlox into warm soil; in most zones that means late spring. Planted then, it flowers from May 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 April. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does Purple Annual Phlox get?
12 intall5 ft 7 inan adult12 inwideSee Purple Annual Phlox 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 Purple Annual Phlox
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space Purple Annual Phlox about 12 in apart, center to center, so each plant has room to reach its full width.
Add Purple Annual Phlox 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
Purple Annual Phlox's height, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil, diseases, pests and toxicity were checked against 9 published sources on August 23, 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.
- Missouri Botanical GardenPlant Finderheight, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil, diseases and pests
- NC State ExtensionPlant Toolboxheight, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil, diseases and pests
- Lady Bird Johnson Wildflower Centerheight, sun, water, bloom months and color, trait tags, soil and pests
- RHSRoyal Horticultural Societysun, water, trait tags, soil, diseases and pests
- everwilde.comEverwilde Farmshardiness zones, sun, water and bloom months and color
- vermontwildflowerfarm.comVermont Wildflower Farmhardiness zones, sun, bloom months and color and soil
- US Forest ServiceUSDA Forest Service, Celebrating Wildflowersheight, bloom months and color and soil
- bbbseed.comBBB Seedhardiness zones
- Lady Bird Johnson Wildflower CenterAsk Mr. Smarty Plantstoxicity
How the checking works, and what each standard covers, is on the verified plants page.
Explore similar plants
You might also like
Foliage
Foliage
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.