Garden phlox (Phlox paniculata 'Robert Poore')

Overview

Phlox paniculata ‘Robert Poore’, commonly known as Garden phlox, is an upright herbaceous perennial prized for its long-lasting, fragrant summer color. This cultivar delivers showy, violet-pink flowers densely packed into impressive terminal clusters, making it a visual highlight late in the season, often extending into the early fall. Garden phlox provides significant visual impact in mixed borders due to its bold habit and vibrant blooms.

Though a staple in the perennial garden, achieving success with Phlox paniculata ‘Robert Poore’ requires attention to its cultural needs, particularly good air circulation to avoid common fungal issues. Its height, reaching 3 to 5 feet, allows it to serve as a strong vertical element in the landscape. Butterflies and hummingbirds are frequently drawn to the nectar-rich flowers of this striking perennial phlox.

Fast Facts

• Plant Family: Polemoniaceae
• Plant Type: Herbaceous perennial
• Hardiness Zones: USDA Zones 5-9
• Size at Maturity:
  • Height: 3-5 ft
  • Spread: 2-3 ft
• Bloom Time: August to September
• Bloom Description: Violet-pink
• Sun Exposure: Full sun to part shade
• Water Needs: Medium
• Maintenance Level: Medium

How to Grow

Plant Phlox paniculata ‘Robert Poore’ in the spring or fall, ensuring it receives full sun for the most robust flowering, although it tolerates light shade. It thrives in moderately fertile, medium moisture, well-drained soils, preferring locations rich in organic matter. Optimal performance occurs in areas with mild summer climates; in hotter regions, ensure ample moisture and afternoon shade.

Water regularly throughout the growing season, as this Garden phlox is intolerant of drought and needs consistent moisture, especially during dry spells. Avoid overhead watering to minimize wetting the foliage, which can encourage disease. Applying a summer mulch helps keep the root zone cool and retains necessary soil moisture.

Maintenance for this perennial phlox involves ensuring good air circulation; space plants properly or thin out stems as needed to combat potential powdery mildew. Deadheading faded flower panicles will prolong the bloom period and prevent unwanted self-seeding. For winter preparation, cut the plants completely to the ground after frost and thoroughly clean up all plant debris to reduce overwintering fungal spores for the next growing season.

Landscape Uses

Garden phlox is a true backbone plant for the perennial border, blending beautifully with later-blooming companions to ensure continuous interest. Its height allows it to anchor the middle or back of a border, mixing well with grasses, asters, or Rudbeckia. Phlox paniculata ‘Robert Poore’ is also highly attractive to beneficial wildlife, making it an excellent choice for inclusion in a dedicated bird or pollinator garden design.

Consider using the strong vertical lines of this cultivar to provide structure against lower-growing groundcovers or mounding perennials. Since it provides long summer bloom, plan companions that offer contrasting textures or bloom times to create dynamic visual layers throughout the season.

Standout Features

Flower Qualities

• Showy
• Fragrant
• Good Cut

Noteworthy Characteristics

Phlox paniculata, commonly known as garden phlox, is native from New York to Iowa south to Georgia, Mississippi and Arkansas. It has escaped gardens and naturalized into areas beyond its original native range. This is an upright perennial that grows in a clump on stiff stems clad with conspicuously veined, opposite, pointed, elliptic, deep green leaves. Fragrant, tubular, pink-purple to white florets are densely packed in large, tiered, domed terminal clusters over a long July to September bloom period. ‘Robert Poore’ is a garden phlox cultivar that typically grows in an upright clump to 3-4’ tall with violet-pink flowers densely arranged in large, terminal, pyramidal clusters in summer atop stiff, upright stems which seldom need staking.

Tolerances

• Deer
• Clay Soil
• Black Walnut

Potential Problems

Phlox is not always an easy plant to grow well, with specific issues demanding preventative care. Powdery mildew is perhaps the most common issue, appearing as dusty white patches on the leaves, especially in high humidity or poor air circulation. To manage this, ensure adequate spacing between plants and avoid overhead watering.

Pests like Phlox bugs and spider mites can also pose challenges, particularly during hot, dry spells. Regular inspection of the foliage can help catch infestations early. Taller stems may require staking if the plant is grown in windy locations or if it is particularly vigorous.

Frequently Asked Questions

What hardiness zones is Garden phlox suitable for?

Phlox paniculata ‘Robert Poore’ is suitable for USDA Hardiness Zones 5 through 9, providing reliable perennial performance across a wide range of climates.

How large does Phlox paniculata ‘Robert Poore’ grow?

This Garden phlox typically reaches a mature height between 3 and 5 feet, with a spread generally ranging from 2 to 3 feet wide.

When does Garden phlox bloom?

This variety reliably blooms from August into September, offering showy, violet-pink flowers that extend the summer color palette.

What sun exposure does Garden phlox need?

For the best results, plant Phlox paniculata ‘Robert Poore’ where it receives full sun, though it can tolerate partial shade, especially in the hottest afternoon hours.

Conclusion

Phlox paniculata ‘Robert Poore’ remains a highly valuable addition to the summer garden, delivering intense fragrance and vibrant violet-pink color atop sturdy, upright stems. By providing rich soil, medium moisture, and excellent air circulation, you can maximize the beauty of this classic Garden phlox and minimize common cultural challenges. Check your local USDA zone compatibility before planning your purchase and planting this season to ensure a magnificent summertime display.

Companion Planting

To create a thriving border around your Phlox paniculata ‘Robert Poore’, select companions that share its need for moist, rich soil and similar sun exposure. Great partners include plants that bloom before or after the phlox peak, such as Baptisia (false indigo) or various ornamental grasses like Panicum. Avoid crowding, as this increases mildew risk; ensure space for air to move around the foliage of your Garden phlox.

Consider plants with contrasting foliage textures, like the fine leaves of Lady’s Mantle or the broader leaves of Hostas if placed in the light shade areas of its acceptable range. These companions help maintain visual interest even when the violet-pink blooms of Phlox paniculata ‘Robert Poore’ are fading.

Wildlife Benefits

The long corolla tubes of the phlox flowers are specifically adapted to attract long-tongued pollinators. Phlox paniculata ‘Robert Poore’ is a reliable source of nectar for both hummingbirds and various species of butterflies throughout its blooming period. Plant this fragrant perennial phlox near seating areas to enjoy both the visual display and the constant activity of visiting pollinators.

The structure of the plant itself, with its dense clump habit, can also offer some shelter or nesting material late in the season, although the primary ecological benefit comes from its nectar offerings. Planting a mass of this Garden phlox creates a significant beacon for migratory species.