You may be driving along the highway and see a field of yellow, white, and pink asters just growing wildly in the middle of nowhere. Actually, these are the Northern Hemisphere native Boltonia, which can be found across the mid- to eastern United States. Also called false aster (Boltonia asteroides), this perennial flower produces ray-like flowers surrounding a yellow center. The cheery flowers last well into early fall and grow well in sandy or gravely moist areas.
I. Appearance and Characteristics
Boltonia asteroides, the white doll’s daisy, false chamomile, or false aster, is a species of plant native to the United States and Canada. It is found primarily in the Mississippi Valley and Great Plains from Saskatchewan south to Texas and Florida, with isolated populations in the eastern United States. Reports of the species in New England, New York, and the Pacific Northwest appear to be introductions.
Boltonia asteroides is a robust, 16″ to 78″ tall (40.6cm to 198.1cm), perennial. It spreads by stolons (horizontal stems running along the surface of the ground). It has many daisy-like flower heads with white or lavender ray florets and yellow disc florets.
The species is sometimes cultivated as an ornamental plant because of its attractive flowers.
Varieties
- Boltonia asteroides var. asteroides – coastal regions
- Boltonia asteroides var. latisquama (A.Gray) Cronquist – Great Plains, Mississippi Valley
- Boltonia asteroides var. recognita (Fernald & Griscom) Cronquist – Great Plains, Mississippi Valley, Ohio Valley, Canadian Prairie Provinces; introduced in New England + Pacific Northwest
II. How to Grow and Care
Sunlight
Boltonia can be planted in partial shade but blooms best in full sun.
Temperature and Humidity
As a native to a wide geographical area, boltonia is highly adaptable to both hot and cold climates. The plant is winter-hardy and is not bothered by high humidity in the summer.
Soil and Water
Boltonia is not fussy about soil; it grows in a wide range of soil types, including clay and areas of seasonal flooding. A soil pH between 5.5 and 7.0 is ideal.
Regular watering is important during the first growing season; once the plant is established, it can tolerate periods of drought but blooms better in medium wet to wet soil.
Fertilizing
Boltonia does not need much fertilizer and too much nitrogen can lead to excessive foliage and no flowers. Usually a one-time application in the spring when the new growth starts is sufficient. Use a bloom-boosting high-phosphorus fertilizer such as 5-10-5, following product label instructions.
Planting Instructions
Plant boltonia in full sun with a slightly acidic to neutral pH. Ideally, the soil should be on the wet side. In its natural habitat, the plant grows in wet meadows, marshes, and along stream banks.
You can plant nursery-grown potted boltonia any time in the spring after the last frost or in the early summer. Dig a hole about twice the diameter of the pot and about the same depth. Place the plant in the hole and fill in original soil to the top of the root ball. Gently tamp down the soil and water it well. Water it regularly during the first growing season to encourage young plants to develop a strong root system.
Space tall varieties 3 to 4 feet apart and dwarf varieties 1 to 2 feet apart.
Pruning
The plants, especially the tall varieties, tend to get leggy and need to be staked when it is blooming in the fall. Cut the stems back by one-third of the length in late spring or early summer to encourage a dense, bushier growth.
Propagation
Boltonia can be propagated by division or from seed. Note that the seeds collected from a cultivar won’t be true to type so you are better off with seeds from a seed company. The seeds need 60 days of cold stratification. In the late winter, plant seeds in pots filled with potting medium and barely cover them, as they need light to germinate. Leave the pots outdoors and keep the soil evenly moist. Alternatively, you can subject the seeds to a 60-day cold stratification in the fridge at 33 to 38 degrees F before planting them outdoors in the early spring.
Potting and Repotting
Boltonia can be grown in pots with large drainage holes and well-draining potting soil. Keep in mind that container plants need more frequent watering and fertilization than plants in the landscape.
In locations with subzero winters, however, growing the plant in pots requires some winterization as the pot exposes the roots to the cold. Keep the plant outdoors during the winter but sink the pot into the ground, wrap it with a thick layer of burlap or bubble wrap, or place the pot in a second, larger pot to create a planting silo.
Pests and Diseases
Boltonia is free of any serious pest and disease issues. It is susceptible to powdery mildew. Boltonia is deer-resistant.
Plants grown in part shade and moist, rich soil tend to develop weak stems and need staking as they mature.
III. Types of Boltonia
- ‘Snowbank’
Boltonia asteroides var. latisquama ‘Snowbank’ is a compact cultivar that only grows 3 to 4 feet tall. It has tiny white daisy-like flowers.
- ‘Pink Beauty’
This tall boltonia cultivar blooms profusely in August and September. The flowers are pale pink with a golden center.
- ‘Nana’
Boltonia asteroides var. latisquama ‘Nana’ is a dwarf cultivar that only grows 2 to 3 feet tall. The flowers are rose-lilac in color with yellow center disks.
IV. Uses and Benefits
There are many landscaping options for this native perennial: at the back of a flower border, in an easy-care native plant or meadow garden, or among shrubs for a burst of late-season flower color. It is also a great choice for a rain garden.
Combine it with other late summer bloomers such as purple coneflower, black-eyed Susan, New England aster, or Japanese anemone. Boltonia looks best when planting in drifts or groups.
V. Boltonia Companion Plants
- Sedum
A fall-blooming sedum such as ‘Autumn Charm’ or ‘Autumn Joy’ is not only a great companion in the landscape but also an addition to the late summer and fall cutting garden. Like boltonia, sedum grows in a wide zone range. Zone 3-10
- Goldenrod
Goldenrod begins displaying its yellow blossoms beginning in late summer and continuing into fall. The goldenrod species vary in their growing conditions so make sure to pick a type that is adapted to your location. Zone 4-8
- Perennial Sunflower
Unlike annual sunflowers, perennial sunflowers don’t branch. They come in varying shades of gold and a softer lemon yellow and make attractive cutting flowers. Despite their extremely soft and airy texture, these are tough plants that are well-adapted to a wide range of conditions. Zone 4-9