Stoke’s Aster

(Stokesia laevis)

• Common Name(s): Cornflower Aster, Stokes’ Aster

• Recommended Use: Herbaceous perennial, landscape, containers

• Exposure: Full sun

• Size: 1-2 feet tall, 18 inches wide

• Habit: Mounded, clumping

• Bloom Time: Mid-spring to late-summer

• Maintenance Category: Low

• Water Use: Average

• Highlights: Native perennial, pollinator attractor, deer and rabbit resistant

Long-lasting flowers extend above the foliage on tall stems. Photo by Ashley Hickman

Summary

Stokesia, or Stokes’ aster, is a low-growing herbaceous perennial in the daisy family (Asteraceae). Stokesia is native to the southeastern part of the United States, and thrives in the warm, humid conditions of southeastern Louisiana. Stokes’ aster has a clumping habit, which means mature plants can be divided in the springtime to expand plantings.

Clumps are formed out of individual rosettes of smooth-margined, thin, pointed leaves ranging from blue-green to bright green. The leaves of Stokesia persist throughout the cold temperatures of winter, making it a good choice for adding visual interest to gardens during months of otherwise barren landscapes. During the summer months, long-lasting flowers extend above the foliage on tall stems. Blooms start opening as early as May and continue through September. Each flower boasts numerous straplike petals in shades of purple surrounding the lighter, central floret disks. Multiple flowers spring up from each clump and remain on the plant after blooms have faded. Though commonly found in shades of purples and blues, white and even yellow, many varieties of Stokesia are available on the market for landscape use. Popular cultivars include purple-flowered Mel’s Blue, Peachie’s Pick and Honeysong Purple; white-flowered Divinity; and yellow-flowered Mary Gregory. A unique cultivar, Colorwheel, sports flowers that start out white and change to lavender before finally deepening into purple. It is not uncommon to find all shades of flowers on one plant as new flowers of Colorwheel open in the summer.

Stokesia performs well in the landscape as a border plant or as a mass planting but can also be used in container plantings as a filler in the thriller-filler-spiller combination. The long flowering stems make them a great choice for cut flowers. These durable perennial plants grow best in full sun with well-drained soil, but can adapt to dry, moist and shaded conditions. Though resistant to most pest and disease pressures, Stokesia is susceptible to root rot when wet soil and cold winter conditions occur together. To prevent plant loss from rot, make sure to plant in well-draining soil and mulch plants to protect roots during the winter. Additionally, Stokesia is not susceptible to grazing from rabbits and deer, which makes it a good choice in areas where grazing is a problem. The summertime flowers provide ample nectar for pollinators, especially butterflies and bees. Deadheading the flowers once they fade will encourage new blooms. Be sure to cut the flowering stem back to the basal foliage for a clean look.

Louisiana Super Plants are chosen based on their reliable performance throughout the state. This native perennial is worthy of the Louisiana Super Plant distinction due to its durability in the Louisiana landscape and adaptability to environmental conditions. The long-lasting flowers make it attractive to people and pollinators alike and a great addition to the home landscape.

Requirements

• Stokesia performs well in full sun (six to eight hours of direct sunlight).

• Irrigate regularly until established (four to five weeks). After establishment, plants can tolerate drier conditions.

• Plants prefer well-drained soil with a pH of 5.5-6.5.

• Plant in the spring after all danger of frost has passed.

Growth Habit

• Stokesia has a mounded growth habit reaching 1 to 2 feet inches tall and 18 inches wide.

• It is suitable as a landscape plant used as a border or a mass planting as well as a container plant.

• Long flower stems make it an attractive choice for cut flowers.

• Space plants 18-24 inches apart.

Care and Maintenance

• Divide mature clumps every few years to keep the planting in check.

• Deadhead throughout the summer to clean up the look of the plant and encourage more blooms by clipping back spent flowers to the base of the plant.

• A general, balanced slow-release fertilizer may be applied in the spring to support growth. Be careful not to over-fertilize.

• Apply mulch around the base of the plants to retain moisture and suppress weeds.

• Stokesia has no major pest or disease issues and is resistant to deer and rabbit grazing.

• Some landscape preemergence herbicide products, such as those containing pendimethalin (Pendulum 2G), are labeled for use around Stokesia laevis. Limited information exists on the tolerance of Stokesia to other commonly used landscape preemergence herbicides such as those containing dithiopyr or trifluralin. Some products allow for use around unlisted species if the user first tests the product in a small area to ensure there is no injury to desirable plants. Consider performing such a test if preemergence herbicides are needed. It is the applicator’s responsibility to follow all labeled instructions when using herbicides.

• Postemergence herbicides containing caprylic and capric acids (Fireworxx, HomePlate, others) may be used in targeted applications to emerged weeds so long as the spray solution does not contact Stokesia shoots or foliage. Follow all product label directions and restrictions when using herbicides.

Ashley R. Hickman is a contributing author.

For more information on Stokesia and other Louisiana Super Plants, contact your local LSU AgCenter Extension office or visit www.LSUAgCenter.com/SuperPlants

P3707-RR
6/1/26
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