To Prune or Not to Prune

by Charlene Burgi

Can you believe we are in the thick of pruning season? Now is the perfect time to check for plants’ structure! Shed leaves allow us to more closely examine and assess our plants’ growing habits, determining what plants need redirection; removal of dead, crossed or broken branches; or general thinning. Some of our plants require proper pruning for better fruit production.

Last year I listed ten rules to follow when pruning. However, there was one factor I didn’t mention or even consider while planning for this task: I have learned when pruning that temperatures can play a critical role in the health and safety of the plant.

“The best laid plans of mice and men often go astray”*

The weather played a huge role in the plans I outlined for this blog. I envisioned taking before and after pictures of either our apple or peach tree so you could see the outcome of proper pruning. Mother Nature had other plans. For over a month temperatures dropped below zero at night and remained well below 32 during the daytime. Ten days of above-freezing weather is needed to avoid potential harm to my trees, but that would put Marin gardeners way behind the curve by the time I could share those pictures. Prolonged frigid temperatures are not a factor you need to worry about in Marin. But it sure wreaked havoc with my plans!

I contemplated the timeliness of this blog and decided to share some good news. Did you know that some plants never need to be pruned? Many evergreen shrubs like daphne, holly and rhododendrons fall into this category and require only an occasional snip for shape.

Other plants such as azaleas, crabapple, lilacs, Philadelphus (mock orange) and flowering plums produce on old wood. Every two or three years they will require your discerning eye and pruning shears, in addition to the annual removal of sucker growth. If you are not certain what flowers on old wood, follow this simple rule of thumb: Most flowering shrubs and trees that bloom in the spring require old wood to produce flowers, and thus annual pruning would eliminate the spring color.

This ninebark requires annual pruning for more intense leaf color.

However, most fruit trees, berries, grapes, roses, crepe myrtle, hydrangeas and other summer-blooming shrubs in our gardens require annual pruning to stimulate new wood growth to produce a bounty of fruit and flowers.

Alas, for every rule there is an exception. Apples, sour cherries, pears and plums do better if pruned for fruit production every other year as they typically develop their bounty on the fruit spurs of old wood.

Pruning. There is so much to be said about techniques, grafting and production for bigger leaves, brighter color, heavier fruit and bigger blooms. Whew! As I mentioned last year—it takes a book to cover it all. And then there is the internet!

* Scotsman Robert Burns, poet and farmer