By: Amy Grant
When fall is just around the corner and the last of the summer blossoms are fading, in march the asters, famous for their late season blossoms. Asters are hardy native perennials with daisy-like flowers prized not only for their profuse late season blooms but also as essential pollinators. Asters are available in a slew of hues, but are there asters that are white? Yes, there are an abundance of white aster flowers to be had as well. The following article contains a list of white aster varieties that make lovely additions to your garden.
Types of White Aster
If you want white aster flowers to accent other specimens in the garden or simply like asters that are white, then there are plenty to choose from.
Callistephus chinensis ‘Dwarf Milady White’ is a white aster variety that, although it is a dwarf variety, doesn’t skimp on bloom size. This variety of aster is heat resistant and disease and pest free. It will bloom profusely from summer until the first hard frost. Their smaller size makes them ideal for container gardening.
Callistephus ‘Tall Needle Unicorn White’ is another white aster flower that blooms late into the season. This variety of aster has large flowers with showy, needle-like petals. The plant reaches a couple of feet in height (60 cm.) and makes wonderful sturdy cut flowers.
Another white aster, Callistephus ‘Tall Paeony Duchess White,’ also called peony aster, has large, chrysanthemum-like blooms. ‘Tall Pompon White’ grows to 20 inches (50 cm.) in height with large pompom blooms. This annual attracts butterflies and other pollinators.
White Alpine asters (Aster alpinus var. albus) are covered in a profusion of small white daisies with sunny golden centers. This native to Canada and Alaska will thrive in the rock garden and, unlike other types of asters, blooms in the late spring to late summer. While Alpinus white asters do not bloom for an extensive period of time, they will freely self-sow if not deadheaded.
Flat Top White asters (Doellingeria umbellata) are a tall, up to 7 feet (2 m.), cultivar that thrives in partial shade. A perennial, these asters bloom with daisy-like flowers in late summer through fall and can be grown in USDA zones 3-8.
False aster (Boltonia asteroides) is a perennial white aster flower that also blooms late into the season. A prolific bloomer, false aster will tolerate wet to moist soils and can be planted in USDA zones 3-10.
For the most part, asters are easy to grow. They are not picky about soil but do need full sun to partial shade depending upon the cultivar. Start aster seeds indoors about 6-8 weeks prior to the last frost in your area or, in regions with a longer growing season, direct sow in a prepared bed of well-drained soil amended with organic matter.
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How to Prepare Aster Flowers for Winter
Asters, also known as Michaelmas daisies, are fall-blooming perennials that come in a large variety of colors and sizes, according to the University of Illinois. Asters can range in size from 6 inches to 6 feet tall, although in most cases the taller varieties need to be staked. Asters grow best in full sun with well-drained soil that is kept moist. Even though asters bloom in the fall, they still need winter protection.
Remove the aster blooms as they fade. Pinch them off at the base of the stem with your thumb and fingers.
Divide your asters, if needed, in the fall after they finish blooming. Dig up the established plants and separate them into two different plants. Plant each new aster in a hole as deep as the root ball and twice as wide. Fill the holes with soil.
- Asters, also known as Michaelmas daisies, are fall-blooming perennials that come in a large variety of colors and sizes, according to the University of Illinois.
- Asters can range in size from 6 inches to 6 feet tall, although in most cases the taller varieties need to be staked.
Water the ground around the asters well before it freezes. Make sure the ground is moist but not soaked.
Cut the asters down to the ground after the ground freezes.
Cover the asters with 2 to 3 inches of mulch to protect the roots during the winter.
Where do you want to send Christmas flowers?
Asters are beautiful perennials that are found wild in North America and southern Europe. The genus Aster includes some 600 species of widely distributed flowering plants in the family Asteraceae.
Kingdom Plantae Division Magnoliophyta Class Magnoliopsida Order Asterales Family Asteraceae Genus Aster
Asters are also called as Starworts, Michaelmas Daisies, or Frost Flowers. Asters are found chiefly in North America, with some species extending into South America others are distributed throughout Europe and Asia. The word Aster is of Greek derivation and refers to the Starlike flowers that can be white, red, pink, purple, lavender and blue, mostly with yellow centers.
The genus Aster is now generally restricted to the old world species, with Aster amellus being the type species of the genus (and of the family Asteraceae). The new world species have now been reclassified in the genera Almutaster, Canadanthus, Doellingeria, Eucephalus, Eurybia, Ionactis, Oligoneuron, Oreostemma, Sericocarpus and Symphyotrichum, but still the new world species are also widely referred to as Asters in the horticultural trade.
Asters are actually 1 - 1.5 - inch flowers. Asters are very complicated flowers. An Aster flower is actually a collection of very tiny tubular flowers, grouped together in a central disk, and surrounded by so-called ray flowers or petals, eg., Sunflower. The central disk of flowers on the Asters is surrounded by the ring of ray flowers. In many cases the disk flowers are a different color than the petals so that the entire flower head looks like a single flower with a central disk surrounded by differently colored petals. The ray flowers on the Asters are never yellow. The tubular flowers of the Asters are bisexual, having both a pistil and stamens the ray flowers are usually sterile.
Some popular varieties of Asters are: Lindley's Aster (Aster ciliolatus), New England Aster (Aster novae-angliae), Many-Flowered Aster (Aster ericoides), Western Silvery Aster (Aster sericeus), Willow Aster (Aster hesperius), Flat-Topped White Aster (Aster umbellatus), Smooth Aster (Aster laevis).
Facts About Asters
- Aster plants are mostly coarse-growing, leafy-stemmed plants that are occasionally slightly woody at the base.
- Most of the Asters are perennials, but a few are annuals and biennials.
- All Asters have alternate, simple leaves that are untoothed or toothed but rarely lobed.
- The leaves of the Aster plant are often dark green and, like the flower petals, can also be long, thin and pointed.
- Asters generally bloom in late summer and fall, but Alpine asters (Aster alpinus) flower in May and June.
- The two main groups of Asters are New England Asters (Aster novae anglias) and New York Asters (Aster nova belgii).
- Asters are one of the easiest garden perennials to cultivate.
- Asters' biggest problem is powdery mildew.
- Asters are used as food plants by the larvae of a number of Lepidoptera species.
- Asters are oftentimes a prime target for birds, bees and butterflies because they are fragrant and colorful.
- Many species of Asters are drought resistant.
- Asters depend on insects to pollinate them. Some insects that take pollen from one plant to another include bees, butterflies, and flies.
- The seeds of Bushy Asters are small achenes, and look like parachutes, which usually spread by wind.
- The China Aster (Callistephus cinensis), also a Compositae, a native of China, is related to the true Asters.
Asters may be propagated by dividing or grown from seed sown indoors at about 70 degrees F or may be sown directly into the garden after all danger of frost has passed. Germination takes anywhere from 15 to 30 days, depending on the temperature.
- Asters should be planted in moist well-drained soil in full sun, but they will tolerate light shading.
- Plant Asters at least 18 inches apart so that plants do not form broad bushy clumps.
- Mature clumps should be divided every 3 - 4 years in the early spring, or late fall after the flowering has finished.
- Pinch back the tops by 6-8 inches at least once during the summer, to create a bushier plant and to prolong the fall bloom.
- Pinching must be done prior to mid July, or it will have an opposite effect, and blooming will be reduced.
How to Manage Perennial Asters
To successfully manage asters, you need to accommodate their natural tendencies, but on your terms.
Here are 21 tips for keeping asters in line, broken down into four categories:
There are some excellent ways to keep plants from taking over the yard, including:
1. Grow them in containers. Choose pots with widths that can accommodate mature plant dimensions, with a depth of at least 12 inches.
2. Deadhead after blooming, to prevent seeds from dropping. Cut the flower stems as they finish blooming, or clearcut entire plants just after the last blossoms fall, before the seeds disperse.
3. Plant in a raised bed with a solid bottom to inhibit root spread. Make it an island unto itself, away from other gardens, to reduce the number of self-sown seedlings that pop up.
4. Divide plant clumps in the spring to reduce their size and disrupt root spread.
5. Manually remove any unwanted seedlings, and place them on the compost pile. To prevent seedlings from growing in the lawn, you can apply a pre-emergent herbicide in early spring. Be sure to use one that won’t kill the grass, and follow the package instructions.
6. Plant them in a location bounded by physical barriers, like a foundation bed beside a paved front path or patio, to inhibit root spread and prevent seeds from dropping on soil.
7. Choose a location where plants may spread without taking over gardens or invading lawns. A fenced roadside property perimeter where you can control their spread is a good option.
8. Place landscaping fabric over the soil around your plants to inhibit seedling growth from self-sowing.
9. Choose smaller, more manageable varieties such as the petite Alpine aster, A. alpinus, that tops out at six to 12 inches tall.
10. Select hybrid cultivars. Hybrids have a higher chance of being infertile, so self-sown seed may not germinate.
A “leggy” plant is one with stems that have grown so top-heavy, it can no longer support them on its own.
This creates a split-open appearance in the clump and can cause stems to break, not only making them unsightly, but also rendering them vulnerable to disease.
11. Pinch off growing tips early in the spring to promote a more compact, bushy appearance.
12. Stake tall species and cultivars like the New England Aster, S. novae-angliae, before they begin to flop over. You can use something attractive and natural looking, like twig fencing.
13. Place shorter varieties in front of taller ones, to help those in the rear position to remain upright.
14. Don’t overfertilize, especially native types. This may contribute to leggy growth.
Address Bare Legs
While naturalized flora requires little supplemental water, during a heatwave they can use a little help. Here’s what to do:
15. If hot weather is predicted, water deeply in advance. Plants that begin to dehydrate are likely to conserve water, starting from the bottom. First the lower leaves will wither, then they turn brown and drop, leaving bare stems.
16. You can place shorter varieties in front of taller ones to hide the bare stems of those in the back, which is especially desirable if the lower portions are dry and leafless. And as mentioned, this also provides support for the tall stems.
Inhibit Fungal Growth
A common issue is a fungal condition called powdery mildew. It generally doesn’t spoil the flowers, but gives the leaves a mottled gray appearance.
Here’s how to keep it at bay:
17. When you are planting, check your seed packet and use mature dimensions as your guide. Make sure you provide ample room between plants, to allow for good airflow and reduce the relative humidity.
18. Weed the garden regularly to maintain good airflow and minimize the relative humidity surrounding your plants.
19. Be careful not to overwater while new plants are becoming established, and during dry spells. Moist, damp conditions are ideal conditions for fungal growth.
20. When watering, aim the hose at the base of the plants, and avoid wetting the leaves. Excessive moisture on the foliage may activate fungal spores.
21. Check plants regularly – especially during damp conditions – for signs of fungal infection, and remove affected leaves. You can apply a fungicide to prevent the disease from spreading.