Fact Sheet

Introduction

As with other members of the Volcano® phlox series, Volcano Ruby is cold hardy to zone 4, but performs equally well up to zone 10 as well, is compact with shorter sturdy stems and very tolerant of powdery mildew that plagues other Phlox paniculata cultivars.

This cultivar grows to 24-28 inches and has a burgundy/purple flower. Compact plants on sturdy upright stems suitable for garden and commercial landscapes.

Key Features

Spectacular burgundy / purple color
Masses of large, fragrant flower clusters
Compact and low-growing with sturdy stems
Flowers from June through September
Ideal in garden beds, borders and containers
Grow in full sun or partial shade
Superior mildew tolerance

Suggested Uses

Ideal summer color for planting in garden beds and borders and container plantings. Excellent in commercial landscapes.

Growth Habit

Compact, branching. Basal growth, branching habit. Upright clump with strong upright stems that don’t require staking.

Plant Size

When mature, 24- to 28-inches tall, up to 24-inches wide.

Flower Size

Up to 1-inch in diameter.

Mature Height

24-28 inches high.

Mature Width

24 inches wide.

Spacing

Plant 12- to 16-inches apart to help natural tolerance to mildew.

Hardiness

Hardy in USDA zones 4 through 10.

Flowering Period

Flowers early Summer until Fall. To prolong blooming, cut back by ⅔ after first flowering.

Number Of Flowers

Large, multi-branched flower clusters, comprised of up to 125 flowers or more per stem.

Flower Color

Burgundy / purple flower.

Fragrance

Pleasant fragrance.

Foliage

Narrow, pointed lance-shaped leaves up to 5-inches long.

Pruning/Pinching

No pinching or pruning necessary in the home garden.

Temperature

Phlox performs best with warm day temperatures and cool night temperatures. Optimal day temperatures range from 75-80°F. Optimal night temperatures range from 50-60°F.

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 Needs

Volcano phlox will tolerate a range of soils but will perform best in a well-worked fertile soil.

Water Needs

Will tolerate moderately dry conditions. Performs best when well-watered. Watering at the base with a soaker hose is encouraged. Overhead watering, or watering at night can promote conditions conducive to mildew.

Fertilizer

In Spring, use a slow release balanced plant food suitable for flowering plants.

Disease Tolerance

Very tolerant but not entirely impervious to mildew.

Pest Issues

Phlox can be affected by spider mites and thrips.

Special Care

Volcano phlox are very mildew tolerant, but it’s good gardening practice in general to take steps to avoid conditions that can promote mildew. Follow spacing recommendations when planting. Crowded plantings can reduce air circulation and promote mildew. Water phlox at the base of the plant and not from above. Soaker hoses are great. Never water your garden at night, as this promotes mildew and other diseases in all plants in your garden. Morning is the best time to water the garden. In zones 4 - 9 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.

Parentage

Selection of Phlox paniculata.