Friday, July 26, 2013

Pruning Mid-Summer

Judging from the calls on the radio (“The Garden Clinic”, Saturdays from noon to 1:00 on WTMA) many people are thinking about doing some pruning.

Pruning in August gets a little tricky, if you are pruning plants that you grow to enjoy their flowers. If a podocarpus, ligustrum, pittosporum or a plant that is grown for foliage not flowers is blocking your walk or driveway, go ahead and prune. The tricky part is camellias and azaleas. Do I prune them?

For the most part camellias have set their flower buds for the fall and azaleas have set their buds for the spring, so you would not want to prune them. However, if you have to do some light pruning for safety or a limb is being a nuisance, go ahead and prune realizing that you might be removing some of your flowers.

A general rule of thumb that has served me well throughout the years is to prune a plant or a fruit bearing tree or shrub right after it flowers or fruits. Of course, there are a few exceptions. Say your camellias and azaleas finish blooming in May, prune heavy enough that they will not need pruning again until next year. If these plants need constant pruning, you may consider transplanting them to another area of the yard that has more room. A general date that would vary with variety is to have all your azaleas pruned by the Fourth of July.

The tricky ones are the plants that bloom on 2 year old wood. Hydrangeas and bananas are the most common plants around here that bloom on 2 year old wood, so you can not remove all the wood to the ground every year or you will not have flowers. In the case of bananas, you have to protect that wood from freezing so they will flower and produce bananas. There is a new variety of hydrangea that blooms on new wood.

When pruning, try to reach into the middle of the plant and open it up.  Take some of the oldest canes down to the base of the plant so it can send out young new shoots from the bottom.  Remove any wood that looks old and unproductive.  Remove any rubbing, sick or diseased looking limbs. Encouraging growth from the middle will also reduce lichen growth. If you have a lot of diseased limbs, consider sterilizing your pruners with a 1% mix of bleach. 

Try not to remove more than 25% of the total plant at one time.  If it is an eight foot plant, don’t hedge it off down to six feet and figure you have removed 25% of the plant.  It is best to use hand pruners and make your pruning cuts where another branch is coming off the limb that you are cutting.   Don’t make cuts along the stem where there is not a branch coming out or you will get two limbs coming out at this point and will create the “shell effect” if done repeatedly. 

The “shell effect” is when you have a veneer of green foliage on the outside of the plant and the middle of the plant has no foliage at all.  This “shell effect” does not allow light and air movement inside the plant making it a haven for disease and insects.  A plant should have layers of green foliage from the top to the bottom, inside the plant and out. 

When you are pruning your azaleas or any other plant at this time of year, make sure you have plenty of mulch and maintain adequate moisture by a good watering schedule.  When you prune the plant, you will be removing leaves that were shading the ground and the root system of the plant will be much hotter, causing it to dry out faster. 

Fleas? Yellowing grass? Sick plants? Keep reading the “Horticulture Hotline”!