How To Divide Asters : Tips For Spitting Aster Plants In The Garden
By: Bonnie L. Grant, Certified Urban Agriculturist
Autumn wouldn’t be the same without the rich tones of aster plants. These fall perennial darlings grow vigorously into small, stout bushes decorated with many daisy-like flowers. Over time, asters can become leggy and flower production will minimize. This is normal but can be corrected by splitting aster plants. Dividing asters will help create a more dense plant with sturdier stems and a full crown of blooms. Read on to learn how to divide aster and what time of year it is appropriate to do so.
When to Divide Aster
Like many perennials, asters benefit from division. You will need to be careful about when to divide asters, as doing so in the wrong season can affect flower production.
Whether you have New England or New York varieties, asters have a long bloom period and lovely, lacy notched foliage. They brighten up fall, when most other blooming plants have ceased to flower. Asters are long lived in pots or in ground, but after two to three years, you may notice the centers dying out and the stems flopping. This means it is time to divide Aster.
Separating asters is best done in early spring. The plant will just be leaving its winter dormancy and new shoots form but no buds will be evident yet. Dividing aster plants in spring will allow the new plants time to establish and even bloom before the end of summer without sacrificing flowers or any new growth.
How to Divide Asters
Perennial division is relatively straightforward. With asters, the root mass spreads so you will be planting the outer growth and discarding the old center roots. Dig around the root base of your aster and down under it carefully to remove the root ball.
Use a sharp soil saw or edge of a shovel for splitting asters. It is important the implement be sharp to avoid damaging the roots as you cut the mass apart. Depending on the size of the plant, either divide into two pieces or three if the plant is established and has not been divided in a while.
Take the edges of the root mass, not the center, which has pretty much done its work. Make sure each piece has plenty of healthy root and stems. Then it is time to plant.
What to Do After Separating Asters
Aster plants that have been divided develop into new bushes, which means the process actually gives you free plants. Once each piece has been inspected for disease or pest problems, it is time to plant. You may either pot up the divisions or put them into the ground.
The soil should be well draining, preferably in an area with at least six hours of sun. Once the roots have been buried to the level at which they were previously growing, water well to settle the soil. Plants should grow just as the parent did, and will need to be fed in early spring with an organic product.
It is a good idea to mulch around the new plants to protect them during winter and prevent competitive weed growth. Your new plants will usually bloom the first year, doubling or even tripling your original investment.
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How to Transplant an Aster
Aster flowers are available in both annual and perennial varieties and come in many beautiful colors such as blue, purple, white, red and an assortment of pinks. While there are many colors of the aster flower, the center of all asters is yellow. These beautiful flowers make a great addition to any garden or landscape, and are easily propagated and transplanted. So, here is a step-by-step guide on how to transplant aster flowers.
Step 1 - When to Transplant
As with many varieties of annuals and perennials, aster flowers should be divided and transplanted in the early spring. You should wait until the last frost before division because young asters are very susceptible to cold weather or frost.
Step 2 - Digging up the Plants
Use a small garden spade to gently dig out the aster plant. Try to remove as much of the root system as possible. If you must cut roots, make sure that you make clean, sharp cuts as far away from the root ball as possible.
Step 3 - Dividing the Aster Plant
Once you remove the aster flower from the soil, divide the plant's root ball into three or four sections. You may be able to separate the roots by hand or you may need to use a pair of scissors to accomplish this. Once you separate the roots, gently shake off any loose dirt or soil that clings to the clump.
Step 4 - Choose a New Location
When choosing a new location for your aster divisions, make sure that you choose a spot that gets direct sunlight for at least 6 to 8 hours a day. Some varieties of aster will grow in the shade, but won't have as many flowers.
Step 5 - Prepare the Soil at the New Location
Prepare the soil for your new aster divisions by turning it with compost and animal manure. If you do not have animal manure available, you can choose to use super phosphate, which can be purchased at home improvement stores and garden nurseries.
Step 6 - Plant the Divisions
Dig holes that are the same depth as those that were used with the parent aster plant and insert your new aster divisions. Gently pack soil around the divisions so that the plants stand upright, but do not pack them too tight that you damage the stems of the plant. Also, make sure to space the plants about 6 to 8 inches apart for smaller varieties and 18 inches to 24 inches apart for a giant sized asters.
Step 7 - Fertilize the Divisions
Apply a quality all-purpose fertilizer to the soil of your new plant divisions. It is also a good idea to add mulch at this time to help protect the new seedlings from insects and pests.
Step 8 - Water the Aster Divisions
Water the new aster plants thoroughly, but make sure not to water them too much. Give them enough water to keep the root system moist, but not too wet. After the asters are established, you will generally only have to water them if there is an extended drought.
Step 9 - Second Fertilization
You should apply a more all-purpose fertilizer about three or four weeks after you plant your aster divisions.
How to lift and divide perennials
Perennial plants that grow in a clump are easy to propagate by division. The clump can be teased apart or chopped up using a sharp knife or a spade. It may look brutal, but it helps rejuvenate plants and increase the vigour of the original plant – as well as giving you new plants for free.