Some types of shrubs can be divided if it has developed new underground shoots. We refer to these shoots as ‘suckers’. They can be propagated by the process of division. You can have many new shrubs for your yard and garden by dividing your shrubs as they mature.
Division is a method of propagation used to provide the gardener with young, vigorous shrubs. Now, you have many young plants instead of just one plant that is getting old and woody in the center.
Many plants can be divided in this manner. Such shrubs as: spireas, lilacs, siberian dogwoods, oak-leaf hydrangeas, sumacs, kerrias, and many others, respond well to this type of propagation. These are the only shrubs to propagate in this manner. Many shrubs will die if you try to divide them. They require other methods of propagation such as layering and tip and root cuttings.
When To Divide a Shrub
The best time to divide a shrub is in the early spring while the shrub is still dormant, just before new growth begins to appear. To get started, use a long-bladed spade, my favorite, and gloves to protect your hands. Make sure the blade is nice and sharp so that it will cut through the roots easily. It is important to make a clean cut so that the plant can heal sufficiently.
Steps to Divide a Shrub
1. Digging Up the Root Ball- Use your spade to free the shrub by severing its roots. Push the spade down into the soil about 6 inches (15 cm) or so away from the crown, so that the blade is angled to be able to get underneath the plant. Do this all the way around the shrub while levering the root ball upward. Try to get any loose dirt off by shaking the spade a bit.
2. Take the Crown Apart- This part may be a little more difficult, depending on the size of your shrub. You may need some extra tools for this job. Maybe having an ax, and loppers on hand, would be a could idea.
Once you get the root ball free, begin separating it into various pieces. Make sure that each piece has a shoot and roots attached. The best way to get started is to look down over the crown and see where you want to make your divisions with your spade,then make those cuts. If the crown is too woody, you may need to use the ax to break a way through so that the spade can get down into it enough to make divisions.
If you have to use the ax, make sure that you use only the outer pieces, since these are the youngest and more vigorous parts of the plant. Continue to pull apart the pieces you need and discard the woody center.
3. Trimming the New Pieces- You should use pruning shears to cut off any underground shoots or torn roots that you see. If your plant is top heavy or will not fit into the hole properly because of roots that are too long, then you should definitely shorten them.
4. Replanting- Inspect the root system that you have on each of your pieces. If they do not have well developed roots left intact, you may need to nurse them for a year or so before planting. Setting them aside in your weed free vegetable garden is a great place to let them gain new roots. If the roots are intact, then go ahead and plant them.
If you are intending to plant your shrub in the same place, you should make sure that clean the hole out thoroughly.
Planting Your New Shrubs
Your new planting hole should be large enough to allow the roots to have enough growing room. Try not to bend the roots or twist them when planting. If you have roots turning upwards, you will need to clip these off.
Next, place your soil around the shrub and firm them down so the plant is stable and well seated in place. Then, water the soil so that the soil settles down around the roots.
If you follow these steps, you should have some nice, healthy plants by autumn.