When to divide asters is a common question for gardeners. Like most perennials, aesters require division in order to grow properly. One of the biggest things division does is stimulate new root growth which will form new shoots into the next year. The new shoot fills in weak areas, an often repeated complaint in aeds that haven’t been divided.
Asters that are properly divided produce huge blooms. Fall perennial or biennials will produce big beautiful flowers in the spring and summer. Many a times it’s easy to miss the big clusters of tulips, daisies or daffodils because they grow so small. These smaller flowers are highly prolific producers. Fall bulbs, though small, have big and very colorful flowers that are perfect for any garden.
When to divide aster plants for best results is in the early spring. Division will give your asters more time for producing new shoots, improving flower production. When you plant them apart they can compete with each other for nutrients and water, causing the plants to weaken and to die.
A good rule of thumb for dividing your aster planting should be about half the width of the container. That’s about half the width of your pot or container. When you divide asters, leave one-third of the roots intact. That’s where the roots are deepest and they will be ready for new shoot growth when you plant them in the fall. The other third of the roots can go in a variety of directions. They can wind up on the ground, through the dirt, or hang down in a tangled mass of roots.
Some species will also produce new leaves from underground stems. So divide your plants if you see this. The main stem and the one-third of the roots should remain attached together. If you see one stem breaking off, remove it and any young roots it was holding down below. Take a new pot and place it in the spot.
Some asters like to grow in soil that has a lot of clay. If you want to divide them, then you will want to plant your divisions in an area with a lot of loose soil. Clay soil holds moisture better than loose soil and can help your plant root system stay healthy. It can also help your aster plant root system hang down more easily, keeping the roots from being so tightly compacted together. You should divide your plant in the late summer or early fall, when the soil is warm and the humidity has begun to dip into single digits.
When to divide asters also depends on how many new shoots you will be getting from your perennials. Asters with a whole series of new shoots (canes or pseudobulb) are going to be easier to get rid of than a plant that just started growing out new shoots. If you need a lot of asters with new shoots you might want to divide the plant during the late summer or early fall before new shoots have set up shop.
Finally, make sure your asters are not growing on stems already broken off by other plants. Asters with stems already broken off will only be more difficult to get rid of. If you notice that your aster plant has stems sticking out of the ground, divide the plant and dig up all of the broken stems and keep them away from your plant. That is the best way to keep a plant from growing on stems already broken off by other plants.
When to divide asters depends a great deal on how long the asters have been in your garden. Asters that have just come out of their last bloom are a bit harder to get rid of than plants that have been around for awhile. If your asters are new to your area, you can divide them right after the bloom period has ended and before the plants start dying back. If your asters have been around for a while and are ready to be divided, remove the whole bunch of them. Blow them off the ground and move them to an open area where they can continue to grow and bloom. That way you can be sure to get the most out of your asters and to ensure that they will bloom again next year.
If your asters are not ready to be divided then do not panic. Just remove the majority of the plants, cut their roots back to about a half inch and move them into a small space that has the proper amount of sunlight, drainage and other requirements for new plants. Just be sure to remove any decaying or damaged roots that may be on the soil.
When to divide asters is something you will know only when you are ready to try it. Springtime can be a wonderful time if you take the time to make sure that you have enough space and properly nourish your asters. If you are not ready to divide your asters during spring, wait until the soil is warm and welcoming. It is a better choice for your gardeners in spring than to attempt to get your plants healthy while the cold weather approaches.