Stokes' aster (Stokesia laevis 'Blue Danube')

Overview

Stokesia laevis ‘Blue Danube’ is a highly valued herbaceous perennial, celebrated for its striking, fluffy, cornflower-like blooms that appear deep sky blue with crisp white centers. This specific cultivar significantly enhances cottage gardens or border fronts, providing reliable summer color. As an evergreen perennial in warmer climates, Stokes’ aster maintains visual interest even outside the main blooming season.

Native to various wet environments along the coastal plain, this plant possesses surprising resilience once established. The key to success with Stokesia laevis ‘Blue Danube’ lies in ensuring excellent soil drainage, as wet feet, especially in winter, are detrimental. Its low maintenance needs and extended bloom time make it an essential addition for gardeners seeking consistent, vibrant blue hues.

Fast Facts

• Plant Family: Asteraceae
• Plant Type: Herbaceous perennial
• Hardiness Zones: USDA Zones 5-9
• Size at Maturity:
  • Height: 1-1.5 ft
  • Spread: 1-1.5 ft
• Bloom Time: June to September
• Bloom Description: Blue with white center
• Sun Exposure: Full sun
• Water Needs: Medium
• Maintenance Level: Low

How to Grow

Plant these perennials in the spring or fall, ensuring they receive full sun for the best flowering performance. While Stokesia laevis ‘Blue Danube’ tolerates filtered sunlight, maximum light exposure is crucial. The most critical cultural requirement is excellently drained soil; average, medium-moisture conditions are ideal, but sandy soils are particularly favored. Wet soil during the winter months must be avoided, as this frequently leads to plant death.

Water moderately and consistently, especially during dry spells, although once established, the plant exhibits good drought tolerance. Fertilization is usually unnecessary if the soil is adequate. Deadheading individual spent flowers encourages the plant to continue producing blooms through September. Remove entire spent flowering stems once blooming slows to tidy the habit.

In the northern reaches of its range (USDA Zone 5), providing a layer of winter mulch helps protect the root system from freeze-thaw cycles. In early spring, cut back any dead basal foliage to refresh the plant’s appearance before new growth emerges.

Landscape Uses

Stokes’ aster, particularly the attractive Stokesia laevis ‘Blue Danube’, excels when used toward the fronts of borders where its unique flower structure can be appreciated up close. They are perfectly suited for traditional cottage garden settings, blending well with Shasta daisies or silver-leaved companions. These plants also thrive near moist areas such as pond edges or stream banks, provided the soil remains well-drained and does not become waterlogged.

For a relaxed, naturalistic look, plant Stokesia laevis ‘Blue Danube’ in small groupings or mass plantings. This technique maximizes the visual impact of the vibrant blue flowers later in the season. Their moderate height makes them excellent transitional plants between low groundcovers and taller background specimens that may require staking.

Standout Features

Flower Qualities

• Showy

Noteworthy Characteristics

Stokesia laevis, commonly known as Stokes’ aster, is native to wetlands, bottomlands, wet pinewoods, savannas and ditches mostly along the coastal plain from North Carolina to Florida to Louisiana. It is an evergreen perennial that typically grows to 1-2’ tall. It features fluffy, cornflower-like, violet blue flowers (to 2 1/2” across), each with notched rays surrounding a pincushion center of feathery disk florets. The cultivar ‘Blue Danube’ specifically showcases fluffy, cornflower-like, deep sky blue flowers spanning 2-3” across, held on erect stems reaching 12-18” tall.

Tolerances

• Rabbit
• Drought

Potential Problems

Flower stems of Stokes’ aster can sometimes develop a tendency to flop, especially after heavy rain or strong winds, although this cultivar is often noted for better stem strength than older types. To manage this, ensure sharp drainage and avoid excessive nitrogen fertilization which can promote weak, lush growth. If flopping is severe, provide very light support early in the season.

In terms of pests, there are generally few serious insect or disease challenges for this species. Gardeners should remain observant for caterpillars, which can defoliate leaves quickly. Maintaining good air circulation and avoiding overly damp winter conditions helps prevent fungal issues.

Frequently Asked Questions

What hardiness zones is Stokes’ aster suitable for?

Stokesia laevis ‘Blue Danube’ is suitable for USDA Hardiness Zones 5 through 9.

How large does Stokes’ aster grow?

This herbaceous perennial typically reaches a mature height between 1 and 1.5 feet tall, with an equivalent spread of 1 to 1.5 feet wide.

When does Stokes’ aster bloom?

Stokesia laevis ‘Blue Danube’ produces its vibrant blue flowers from June all the way through September.

What sun exposure does Stokes’ aster need?

For optimal growth and maximum blooms, Stokesia laevis ‘Blue Danube’ requires full sun exposure in the garden.

Conclusion

The combination of low maintenance, evergreen foliage, and spectacular flowering makes Stokes’ aster an indispensable addition to perennial beds. If you are seeking reliable, vibrant blue color that resists damage from rabbits and tolerates periods of dryness, Stokesia laevis ‘Blue Danube’ is an excellent choice. Always confirm your garden’s hardiness zone compatibility before planting this superb specimen.

Companion Planting

When selecting companions for Stokesia laevis ‘Blue Danube’, focus on plants that share its preference for full sun and excellent drainage. Consider pairing it with silver-leaved perennials like Lamb’s Ears (Stachys byzantina) to contrast its deep blue color and accentuate its airy texture. Plants with fine, airy textures, such as certain ornamental grasses or slender spike flowers like Salvia, will play nicely against the bold, aster-like blooms of Stokes’ aster.

Consider plants that thrive in slightly drier soils once established, such as Lavender or Yarrow (Achillea). This mimics the varied conditions often found in its native habitat while ensuring no companion plant demands excessively wet feet around the base of the Stokes’ aster.

Design Ideas

Stokes’ aster is highly versatile in landscape design due to its manageable size (1 to 1.5 feet tall). It shines when used as an edging plant along pathways, providing a soft, continuous blue line throughout the summer. For a classic English garden feel, intersperse clumps throughout mixed perennial borders, allowing them to intermingle naturally with spikier flowers.

Mass plantings of Stokesia laevis ‘Blue Danube’ create a stunning visual statement, particularly when viewed from a distance across a lawn area. Since the plant has good drought tolerance, it is an excellent choice for sunny, slightly elevated areas where drainage is naturally superior and where conservation of water is a priority.