With all the glory going on outside my window at the moment, it's hard to believe this week's topic is about summer flowering shrubs. At a time when the lilacs are just coming into their full bloom, and the sight of the dogwood trees in flower around town are enough to stop traffic, why would anyone in their right mind want to talk about plants whose showy season is so far off? Let me explain why this is such a good idea.
Most gardeners are familiar with the term transplanting shock, which is loosely described as the phenomena of a plant being placed in a stressful state by the rigors of planting. There are many contributing factors to the total amount of stress a plant will have to endure while being transplanted. Lack of water, high temperatures, rough handling and a host of other conditions that add up to greater and greater stresses being heaped upon the plant all lessen the chance that our faithful transplant will survive. As good gardeners, we try to eliminate, or at least lessen, each stress that the plant will face. To do this, we must first identify those conditions.
Summer planting, to be successful, requires recognizing more of those factors than at any other time of the year. To sum it all up in one neat sentence: plant summer flowering shrubs now for the highest percentage of transplant survival. I am a landscape contractor with 30 years of planting experience in the heat of our summers in the Rogue Valley. It can be done. There is a whole set of different rules that come into play at that time of year. Many gardeners wait until a plant comes into flower before they buy it. Or they just have their eye caught by a showy display by a shrub in bloom at the nursery and they make an impulse buy. Let's look at how plants respond to being planted while in bloom.
It is the main mission of most of the life on this planet to reproduce their genes through their progeny. For many plants this accomplished by the formation of flowers, followed by seed. This is the reproductive part of its life cycle. The fewer the number of flowers that a plant is likely to produce, the more seriously it protects each one. During the flowering period there is little energy devoted to the other processes that otherwise occupy the plant. Foliar growth slows or ceases altogether. The same is true of root growth. There are few, if any, advances in growth made at this time. The focus, just like our eye, is on the flower.
How do you think a plant responds to being shaken out of a container, having its roots spread apart, then being slammed into a dry hole and backfilled with hot dust, waiting several hours before being watered in? Then, we try to make it up to the plant by adding some vitamin B1 to the water to lessen transplant shock. Each wrong step adds up quickly in hot weather to equal total failure if you are unaware of the stresses that your transplant will face. We haven't even accounted for triple digit temperatures, drying winds or root-bound plants!
Fortunately, there are many wonderful summer-flowering shrubs tha respond beautifully to being planted now when stresses are much lower. Some of my favorites are: abelia, butterfly bush, summer heathers (calluna and daboecia), blue beard (caryopteris), crape myrtle, escallonia, hebe, and oleander (for warm spots only). All, except the heathers, enjoy a bright sunny spot in the yard, out of competition with trees and lawns. They all have a long bloom season extending through summer into fall. They are not particularly prone to insects or diseases. Watch for earwigs on butterfly bush during the spring months and escallonia may be subject to some leaf spotting caused by fungus during the winter.
It's hard to keep your eye out for plants that are not in bloom when strolling through a nursery. You will be glad you did when you find how easy it is to plant summer-flowering shrubs at this time of year.
Stan Mapolski, aka The Rogue Gardener, can be heard from 9-11 a.m. Sunday mornings on KMED 1440 AM and seen in periodic gardening segments for KTVL Channel 10 News. Reach him at firstname.lastname@example.org.