Luminary Ultraviolet (Phlox paniculata 'Ultraviolet') - purple flowers, illustrated plant cardIllustration

Luminary Ultraviolet

Phlox paniculata 'Ultraviolet'

Also called ultraviolet tall garden phlox and luminary ultraviolet phlox

Luminary Ultraviolet blooms from July through August.

Bloom calendar
Bloom time
Jul–Aug
checked
Hardiness
Zones 3–8
checked
Sun
Full sun
checked
Water
Moderate water
checked
Mature size
2.5 ft × 2.5 ft
checked
Type
Perennial
house classification

Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.

Growing Luminary Ultraviolet

Plant it in full sun. It prefers moderate water. It is hardy in USDA zones 3–8. Expect it to reach about 2.5 ft tall and 2.5 ft wide at maturity, in roughly 2 years (a house reading).

No toxicity note is on file for Luminary Ultraviolet. That is not a clearance: check its safety for people and pets before planting.

Verification
What was checked

Mature height and spread, hardiness zones, sun, water, bloom months and color and the trait tags were checked against named botanical sources for this plant, with what the sources could not settle written down; years to mature size rests on a recorded house rule where no publisher states one, and is marked so; its common name and alternate names have not been checked yet. 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.

See the 11 sources it was checked against

When to plant Luminary Ultraviolet

Plant Luminary Ultraviolet 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 5, the middle of its hardy zones 3 to 8, spring means April to June and fall means August or September. Once settled, it blooms from July to August.

Month-by-month timing for your zone is on the planting calendar; if you garden near zone 5, the middle of this plant's hardy range, start with zone 5 in April. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.

How big does Luminary Ultraviolet get?

Illustration of Luminary Ultraviolet drawn to scale beside an adult2.5 fttall5 ft 7 inan adult2.5 ftwide
About 2.5 ft tall and 2.5 ft wide at maturity: thigh-high beside an adult.

See Luminary Ultraviolet 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 Luminary Ultraviolet

Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.

Space Luminary Ultraviolet about 2.5 ft apart, center to center, so each plant has room to reach its full width.

Plant them
2.5 ft apart
Per 10 sq ft
about 2
4 by 8 ft bed
about 3

Add Luminary Ultraviolet 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

Luminary Ultraviolet's height, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil, diseases, pests and toxicity were checked against 11 published sources on September 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
  • Walters Gardensthe breeder and introducerheight, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil, diseases and pests
  • midwestgroundcovers.comMidwest Groundcovers (a wholesale nursery that grows the plant, St. Ch...height, spread, hardiness zones, sun, water, bloom months and color and diseases
  • US plant patent (Google Patents)US Plant Patent PP33,607 (Hans A. Hansen, assigned to Walters Gardens,...height, spread, hardiness zones, bloom months and color, trait tags, soil and diseases
  • Plant Addictsa nursery that sells the plant; the queue's storeheight, spread, hardiness zones, water, bloom months and color and soil
  • whiteflowerfarm.comWhite Flower Farm (a nursery that sells the plant, Litchfield, Connect...height, spread, hardiness zones, sun, bloom months and color and diseases
  • Proven Winnersthe introducer's brand; one voice with Walters Gardensheight, hardiness zones, sun, bloom months and color and soil
  • agsci.psu.eduPenn State Flower Trials (2021 sun ground trial, Southeast Agricultura...height, spread, bloom months and color and trait tags
  • NC State Extensiontrait tags, soil, diseases, pests and toxicity
  • ASPCAAnimal Poison Control, Toxic and Non-Toxic Plantstoxicity
  • Plant AddictsAre Phlox Poisonous?, a genus-level articletoxicity

How the checking works, and what each standard covers, is on the verified plants page.

The Garden Phlox group

One of 14 in the Garden Phlox group. Same plant, same care.

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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.

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