The New York aster is an important border perennial for the autumnal bed and is – from a horticultural point of view – one of the most valuable asters ever. Here you will find the most recommended varieties and how to properly plant and care for the pretty autumn flowers.
Profile of New York aster:
Scientific name: Symphyotrichum novi-belgii
Plant family: aster, daisy, composite, or sunflower family (Asteraceae)
Other names: Michaelmas daisy
Planting time: spring or autumn
Flowering period: August to November
Soil quality: loamy, nutrient rich, humus rich, calcipholous
These information are for temperate climate!
Use in: flower beds, bouquets, single position, group planting, planters, borders, cottage garden, flower garden, prairie garden
Winter hardiness: hardy, USDA Plant Hardiness Zones: 2 (-43 °C / -45 °F)
Bee and insect friendly: Yes
Plant characteristics and classification of New York aster
Plant order, origin and occurrence of New York aster
The New York aster (Aster novi-belgii) originally comes from North America and is widespread from Newfoundland to Quebec and south to Georgia. There it naturally grows in damp places, on river banks, on railway embankments and in swamps in the coastal areas. It was introduced to Europe as a garden plant in the 18th century. It is often – based on its botanical name – also known as the New Belgian Aster. How it got this name is a bit strange, as there has never been a place or region called New Belgium. It was created by a German botanist named Paul Herrmann in 1687, who wanted to name this aster “New Holland”, the former name for the east coast areas between Philadelphia and the Canadian border. When translating into Latin, the unusual name “novi-belgii” came into being, which still exists today. Because of the genetic peculiarity of North American aster species, the genus classification is discussed and changed again and again, which is why the New York aster is botanically considered to be the Symphyotrichum genus today. So far, this name has not prevailed in trade and especially among amateur gardeners and this species is still listed as Aster novi-belgii.
It is also known as “Michaelmas daisy” because it blooms around September 29 which is St. Michael’s Day.
The New York aster belongs to the aster family (Asteraceae).
Characteristics of New York aster
The New York aster grows up to 1.5 meters (5 ft) high and has an upright, round stem. In addition, it is bald in all parts, grows bushy and forms short runners. Genetically, it is almost identical to rice button aster (Aster dumosus), which is why there are always problems with classification. In the meantime it has been agreed to assign all varieties under 50 centimeters (20 in) in height to Aster dumosus, all higher varieties are counted as Aster novi-belgii. Because of the numerous cultivations, the line is blurry here.
The medium green leaves of the New York aster are between 5 and 15 centimeters (2 and 6 in) long and are lanceolate. The leaves are between four and ten times as wide as they are long. Some also have a serrated edge, but most varieties have entire edges. They have no stem and cover the stem half.
The 2 to 4 centimeter (0.8 to 1.6 in) ligulate flowers are arranged in large corymbs and appear from September to October. The flowers of the New York asters are usually purple, but they can occasionally also be bluish, pink or white. During the flowering period, the perennial is covered with flowers all over.
New York aster – cultivation and care
The New York aster thrives best in sunny, cool and airy locations.
The New York aster prefers a nutrient-rich, loamy-humic and freshly moist soil, because the large bushes need plenty of nutrients for their annual growth. It is important that the soil does not dry out even in summer, otherwise the flower development will suffer and the risk of mildew infestation will increase.
Because of their height, the New York asters are best planted in the middle and back area of a bed and combined with low shrubs. In order to prevent powdery mildew, the plants should not be planted too densely.
Care / Watering / Fertilization /
Since the risk of mildew infestation is generally very high and increases further if the location and the nutrient supply are not optimal, regular watering in dry conditions and annual fertilization in spring with a long-acting perennial fertilizer are very important.
Higher varieties should also be supported.
Pruning should be done after flowering in late autumn or in spring before budding. If you cut back in late autumn, you should also cover your New York asters with a nutrient-enriched compost. So they start the new season well supplied and at the same time have additional protection in winter. Especially with tall shrubs it is advisable to shorten the tips of the shoots before flowering. But be careful: the flowering time is postponed by about 20 days.
You should regularly dig the plants out of the soil, divide and replant them again in order to maintain the blooming over the years and to promote the vitality of the plants. Older plants are best only replanted in small subplants or cuttings with three to five basic shoots elsewhere in the spring. In the same year they produce very vigorous, healthy and abundantly flowering plants.
The easiest way to propagate New York asters is to split them after flowering or in spring.
Diseases and pests
Most New York asters are very susceptible to mildew. The risk of mildew infestation can be reduced by consistent soil moisture and an adequate supply of nutrients. The susceptibility is strongly dependent on the variety, so when purchasing a New York aster you should definitely pay attention to variety recommendations and the results of examine the perennial.
The New York aster is very hardy down to -43 °C / -45 °F. So there is no further winter protection necessary.
Use in the garden
New York asters not only look good in a sunny bed, but are also good as cut flowers that can be beautifully tied to autumnal bouquets. Suitable planting partners include other aster species, such as button asters, which can be placed directly in front of the New York asters, low-growing perennials such as catnip (Nepeta) or dog daisies (Leucanthemum). Particularly attractive combinations arise with ornamental grasses such as the foxtail fountain grass (Pennisetum alopecuroides) or switchgrass (Panicum virgatum), the blades of which play around and loosen up the rather stiff shape of the aster.