Product Field NotesCompanion Plants
Riptide Stokes' Aster: Periwinkle Blooms After Lavender Peaks
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Riptide Stokes' aster is a Stokesia with strong basal branching, which means far more stems and far more flowers than older types. The flat, cornflower-like blooms are 2.5 to 3 inches across, periwinkle blue with a fringed outer ring and a finely cut purplish center. It is reported to produce up to about 400 flowers in a season, and at peak the dark green mound nearly disappears under them.
Riptide at a glance
| Trait | What to expect |
|---|---|
| Botanical name | Stokesia laevis 'Riptide' |
| Flowers | Periwinkle blue with purplish-blue centers, 2.5 to 3 inches |
| Foliage | Rich dark green, smooth and lance-shaped |
| Size | 24 to 26 inches tall, 32 to 36 inches wide |
| Bloom | Starts mid-July, peaks early August, continues into fall with deadheading |
| Hardiness | USDA zones 5 to 9 |
| Light | Full sun |
| Wildlife | Great for pollinators and butterflies |
Carrying the color past harvest
On a lavender farm, mid-July is when the bundles come in and the plants get their summer trim. That is right when Riptide gets going. Its blue-purple flowers are close enough to lavender's palette that the bed still looks like a lavender planting in August, just with bigger, flatter blooms. Plant it at the front of a lavender bed or between groups of plants, leaving room for its 3-foot spread.
The growing conditions line up well: full sun and soil that drains, with some dryness tolerated once it is established. It adapts to poor or fertile ground, so it will not need special treatment in a lean lavender bed. Sketch the layout in the Companion Plant Planner.
Planting and care
- Site: full sun in well-drained soil, poor or fertile.
- Water: regularly the first season, then during long dry spells.
- Heat: very heat tolerant; a southeastern native that keeps blooming through hot summers.
- Deadheading: snip spent flowers to keep new buds coming into early fall.
- Airflow: it handles humidity well, though foliage stays cleaner with room around it.
Winter in Michigan
Riptide is hardy in zone 5 Michigan gardens when the soil drains well. Wet winter soil, not cold, is what causes crown rot. Leave the low basal rosette of leaves in place over winter, add a light mulch after the ground freezes in colder spots and tidy dead leaves in spring. Confirm your zone with the USDA Zone Finder.
Cutting and containers
The flowers rate good for cutting and look lovely with late lavender stems or white phlox. Riptide also does well in a large container in full sun with a fast-draining mix.
Frequently asked questions
Is Stokes' aster a true aster?
No. It is a separate plant, Stokesia, that looks a bit like a cornflower and blooms earlier than most fall asters.
How is it offered?
As a full 72-cell plug tray, good for mass plantings and growers. See the product page for current availability.
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