October 13, 2016
We finally had the soaking rain that our plants have desperately needed. Let’s hope that we get a few more soaking rains without it being caused by a hurricane.
There have been a few questions about cutting back perennials in the fall. As an example, someone asked if they could cut back their hosta leaves. Leafy plants, such as hosta, will lose their leaves to the first frost. For some of you, early Tuesday morning brought the first frost. At this point in time, you should cut back the leaves that have been killed by the frost. At this point in the year, you can cut back the leaves even if the frost hasn’t killed the leaves. Once you have cut back the leaves and stems of your perennials, make sure to clean up the debris. This will help to prevent the spread of diseases and it will help to eliminate a winter home for over wintering insects. Once the plants are cut back, an application of superphosphate can be applied to your perennial beds. This type of fertilizer will help to stimulate new root growth. After the summer we had, you can be pretty sure that the roots of your plants suffered some damage. The superphosphate will also remain in the soil to a certain degree. Along with stimulating root growth, come the spring, the phosphorous will also help in flower production on your flowering perennials.
The next most popular question this fall has concerned pruning back flowering shrubs. In some cases, the plant is very overgrown and the customer wants to “rein in “ the growth. If the plant is a spring flowering shrub, the flower buds for Spring 2017 have already set on the plant. If you prune back the spring flowering shrubs now, you will be removing the flowers that you would have in the spring. If you can live with that to make the plant smaller, then it would be OK to prune back now. Otherwise, spring flowering shrubs should be cut back as soon as they are done flowering in the spring. Summer flowering shrubs, such as butterfly bushes can be pruned in the fall once the frost has knocked back the leaves. You can prune them in the spring if you prefer. A pruning in the spring will increase the amount of new branches, which in turn will mean more flowers being produced. After pruning, an application of superphosphate will help to repair the root system and also help with flower bud production come the spring.
As a rule of thumb, you do not prune back your hydrangeas in the fall. There are exceptions to this rule, but if you have the blue hydrangeas, the majority of them produce their flower buds on the growth that formed this summer. The flowers then open in 2017. For this reason, you would not prune back in the fall. You also want to take steps to protect those hydrangeas from the drying winter wind. Hydrangeas don’t have a thick bark. It is very easy for winter winds to pull moisture out of the branches and to ultimately kill those branches. You can wrap the plant with burlap or you can apply an anti-desiccant spray to the canes once the leaves fall off the plant.
Well, that is some information to help you through the pruning process. I hope it has cleared up some questions you may have had.
Well, that’s all for this week. I’ll talk to you again next week.