Boltonia [bol-TO-nee-uh] is a genus of plants mostly native to North America, including the Great Plains and the Mississippi Valley.
These plants belong to the Asteraceae family, which also includes the chamomile plant.
The Boltonia genus only includes a handful of native plant species, including the popular Boltonia asteroides, also known as:
- False chamomile
- False aster
- White doll’s daisy
It’s a robust perennial plant with stems reaching several feet tall.
It produces many daisy-like flowers and is often grown as an ornamental plant.
Boltonia Asteroides Care
Size and Growth
Most varieties of Boltonia grow to about 5’ – 6’ feet tall with branching stems covered in lance-shaped leaves.
The leaves often measure 5” inches long and the foliage isn’t dense.
The stems are sometimes too thin to handle strong winds.
When grown in open areas, plants often require stakes for support.
Flowering and Fragrance
The flowers are the main reason why people cultivate false aster plants.
Boltonia aster is the most popular choice, producing white daisy-like flowers with large yellow centers.
Some varieties also produce yellow center disks tinged with pink, violet, or purple.
Most Boltonia plants are late bloomers with bloom time from late summer to early fall.
Light and Temperature
Boltonia plants grow well under full sun to partial shade.
However, if conditions get too shady, the stems may not grow thick enough to support the plant.
Due to its height and spread, it’s rarely grown indoors.
It’s best suited for use in gardens where it can remain year-round.
Suitable for growth in USDA hardiness zones 3 to 9, false chamomile can survive freezing temperatures in the winter.
Watering and Feeding
Boltonia plants are typically easy to care for and only require occasional watering, especially when grown in garden beds.
It tolerates moist soil, and high humidity levels, so overwatering is rarely a problem.
Feed the plant every two weeks during the growing season using a liquid fertilizer. Don’t fertilize during the winter.
Soil and Transplanting
Sow seeds in well-drained soil or near wet, marshy areas.
As mentioned, people rarely grow Boltonia plants in containers, but it’s possible.
Repot when plants outgrow their container. Frequent handling may damage the thin stems.
Pinching helps produce thicker growth and provides a way to keep tall plants from collapsing from strong winds.
If the plant can’t support itself or produces leggy growth, cut back the stems in late Spring or early Summer.
Never trim the stems back more than one-third of their current size.
How To Propagate False Aster?
Propagate Boltonia plants by seed or division.
Propagating by Division
- Separate the plant in the spring or fall.
- Dividing the plant every two to four years helps control the spread of the plant and maintain fuller growth.
- Carefully remove the plant from the soil.
- Use caution to avoid breaking or bending the stems.
- Cut the root system into two or three sections.
- Plant in a rich, well-drained potting mix using the same plant care tips as for mature plants.
Propagating by Seed
- Sow seeds in the fall using a propagating tray.
- Cover the tray with plastic and place it in a bright spot.
- The seeds should germinate within two to three weeks.
- After the seedlings appear, remove the plastic cover and water occasionally.
- By the following spring, the seeds should be ready for planting in the garden or a large container.
False Aster Pest or Disease Problems
Boltonia plants may develop powdery mildew caused by dry conditions.
This mildew is a type of fungal infection that may spread without treatment.
- The mildew resembles dirt or dust on the tops and bottoms of the leaves.
- If it appears, make sure the potting mix isn’t draining too fast.
- Add clay or sand to the mixture to limit drainage and give the plant enough moisture.
- After checking the mix, use a homemade solution to wash away the mildew.
- Mix baking soda with liquid soap and water.
- Spray the mixture on the leaves.
- If this does not remove the mildew, try using a combination of milk and water.
- Combine one part milk with three parts water and spray the leaves.
- The milk acts as an antiseptic and fungicide.
- If the homemade solutions don’t work, use a commercial organic fungicide.
Other than the mildew, Boltonia varieties don’t have any serious pest or disease problems.
When these pests arrive, move the plant outdoors and shower it with cold water.
Adding dish soap to the water may also help remove the critters.
If the pests remain, use an insecticide (organic neem oil) but avoid bringing the plant back indoors until the infestation is gone.
Outdoor plants may attract insects and butterflies. However, they rarely pose a threat.
Suggested Boltonia Uses
Deer-resistant false aster plants, help add color to any garden.
Consider pairing it with shorter flowering plants blooming earlier in the season to enjoy more color throughout the year.