Volcano® Phlox



Volcano phlox are compact, low-growing with sturdy stems.  They’re exceptionally tolerant of the powdery mildew which plagues most other phlox varieties and produce an astonishing number of flowers from June through to September.  Unlike most varieties of phlox paniculata,Volcano are heat tolerant, performing well even in USDA Zones 8-10.

Volcano was selected the Perennial of the Year as part of the “Oklahoma Proven” promotion program coordinated by faculty in the Department of Horticulture and Landscape Architecture at Oklahoma State University.

 Suggested Uses

  • Great in garden beds and borders
  • Can be used in larger containers
  • Lovely as a cut-flower

Planting Information

  • Growth Habit: Compact, branching. Basal growth, branching habit. Upright clump with strong upright stems that don’t require staking
  • Spacing:  plant 12-16 inches apart (30-40cm) to help natural tolerance to mildew
  • Mature size: up to 24 inches wide (50cm) and 36 inches tall (90cm)
  • Hardiness: USDA Zones 4-10; more heat tolerant than most other garden phlox (phlox paniculata)
  • Light needs:  Performs best in full sun (six hours of sun daily), but will tolerate partial shade (minimum four hours of sun daily). Best in partial or full shade in hot climate zones.
  • Soil requirements: will tolerate a range of soils but performs best in well worked fertile soil.
  • Water needs: Will tolerate moderately dry conditions but performs best when well-watered at the base by soaker hose or low watering tool.
  • Temperature needs: Phlox perform best with warm day temperatures and cool night temperatures.
  • Disease tolerance: Very tolerant but not entirely impervious to mildew
  • Flowering Period: June through early frost if deadheaded after first set of blooms fade.
  • Maintenance: because they’re very heavy bloomers, Volcano phlox should be fed several times throughout the season.  Divide Volcano Phlox every 3 to 5 years or when the plant looses vigor or the center of the clump starts to die. Divide in early spring for best results.


Key Features

  • Masses of large, fragrant flower clusters
  • Compact and low-growing with sturdy stems
  • Flowers from June through September
  • Grow in full sun or partial shade
  • Superior mildew tolerance
  • Hardy in USDA Zones 4-10
  • More heat tolerant than most other phlox paniculata varieties


Varieties Available

Download a print-friendly plant fact sheet PDF here: Volcano® Phlox 1.6MB
Download a print-friendly plant photo gallery PDF here: Volcano® Phlox 6.8MB






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