This fall we've been getting lots of shrub related questions ranging from transplanting to pruning to protecting them in the winter. These were all great questions so I thought I'd make this month's tip all about fall shrub care.
In general, the best time to move or transplant shrubs is when they are dormant. Depending on where you live, this can be any time from late fall through early spring as long as the ground is not frozen or overly wet.
It's easy enough to tell when deciduous shrubs like hydrangea are dormant because they lose their leaves but for broadleaf evergreens, like rhododendron, holly, and boxwood, it's not as clear cut.
Normally, evergreens enter dormancy in the late fall around the same time as deciduous shrubs, however, since they don't lose their leaves, they continue to function physiologically but at a reduced rate. Because of this, some experts recommend that evergreen shrubs should not be moved until late winter or early spring. Why? Evergreens continue to lose water through their leaves during the winter and since many of the small water absorbing roots are removed or damaged when a shrub is dug, the remaining root system may not be able to absorb enough water to replace the water that is lost. This leaves the shrub prone to winter burn.
If you DO need to move an evergreen in the fall, water it well after planting and then spray with Bonide Wilt Stop to help reduce water loss from the leaves and reduce transplant shock. Always follow the label directions.
Before you dig your shrub to move it, be sure to first prepare the new planting hole. Select the new location keeping in mind the cultural requirements of the shrub and its size at maturity.
Give it plenty of space, you don't want to have to move it again!
Once you have prepared the new planting hole, you are ready to dig up the shrub you are going to move. It is very important to dig as large a root ball as you can handle, but the size will depend upon the size of the plant.
Sometimes, especially for evergreens, it is beneficial to root prune before digging the shrub. If you have time to wait before transplanting, this increases the rate of success . It encourages the formation of new feeder roots and reduces transplant shock. Root pruning can be done in the early fall in preparation for moving the shrub the following spring.
Hybrid Tea Roses
Often during a hard winter, the stems of hybrid tea roses can break at the base due to snow or ice build-up on the plant. Late October and November is a great time to tip back these roses.
- Prune hybrid tea roses back to about 30" from the ground. This should help prevent damage from the weight of ice and snow.
- In the spring, after the danger of cold weather, is the time to do the main pruning of these roses.
Boxwood and Holly for the Holidays!
Pruning of boxwood and holly is done mainly to control size and shape, and to improve the health of the shrub. Annual thinning with hand shears is recognized as one of the best pruning methods for maintaining the health of the shrub. Happily, you can do this type of thinning in early winter when the trimmings can be used for holiday decorating!
Click for tips on thinning boxwood. Holly can be cut for holiday greens in the same way.
Do not prune spring blooming shrubs like azalea, forsythia, and rhododendron in the fall or you will be cutting off all the blooms. The time to prune spring bloomers is right after they finish blooming in the spring.
In colder zones, fig trees and certain shrubs like Hydrangea macrophylla, miniature roses, and newly planted roses may need to be provided with some sort of winter protection.
A good way to accomplish this is to surround the shrub with black roofing paper and carefully pack straw or oak leaves inside around the branches and stems. Use stakes to hold the cylinder of roofing paper in place. If the shrub is very wide, you can carefully draw the branches together with twine before making your enclosure of roofing paper.
The black roofing paper is ideal because it not only provides a wind screen, but it also absorbs heat from the sun and keeps the shrub warmer in the winter. You can use burlap in the same way but it doesn't absorb heat the way the roofing paper does.
Oak leaves are the best type of leaves to use as an insulator because they are more resistant to rot and seem to drain better. Maple leaves, sweet gum, and tulip leaves mat easily and get mushy when they get wet. They also breakdown faster than oak leaves. Pine needles are also an excellent choice for insulation.