Shrubs for Summer Color
by Dennis Patton, horticulture agent
It will not be long before we hear the crack of the bats at Kaufman Stadium. The “boys of summer” will be returning for another exciting season at The K. Will this year lead to another return to the World Series? Baseball is America’s summer sport. Just like sports have their seasons for taking center stage, so do our landscape-worthy shrubs.
Summer is a fun time in Kansas City. But as we all know it can be hot and dry. We long for color to help get us through these more uncomfortable weeks of the year. Nothing puts a smile quicker on our face than colorful flowers to freshen up summer. If you think shrubs are just for spring color then think again. Here are four outstanding summer shrubs to help you hit a grand slam.
Caryopteris, or Blue Mist Spirea, is a wonderful addition to the garden. This plant, while called a spirea, is not closely related to our traditional spring blooming plant. Instead, this shrub is an extremely heat and drought tolerant plant which will thrive in full sun and less than desirable soil conditions. The plant is also smaller, around 3 feet by 3 feet.
Care for Caryopteris is simple, even for novice gardeners. This is considered a “cutback” shrub. Each spring prune back to about 6 inches from the ground. This encourages a flush of new growth on which the bluish flowers will be borne in July and August. The foliage is a nice dusty gray that adds interest to the landscape, as this color pops in the garden. Another great feature of this plant is that it is a good nectar source for butterflies and beneficial insects.
There are several varieties available on the market including ‘Dark Knight,’ ‘First Choice,’ and ‘Petit Bleu.’ There are a couple of varieties that have a golden hue to the foliage, such as ‘Worcester Gold’ and ‘Jason.’ These tend to have nice foliage but less flowers.
When you first hear the word hydrangea you probably immediately get this image of a big mophead covered in pink or blue flowers. That image would be the more fussy and difficult to grow species, Hydrangea macrophylla. But the hydrangea of summer is Hydrangea paniculata, or the Panicle Hydrangea. The Panicle Hydrangeas are much more forgiving and better adapted to the Kansas City climate. These plants will thrive in full sun to light shade. The one downside to this plant is that it will require supplemental watering during the hot, dry parts of summer to thrive.
Panicle hydrangeas have white flowers and a long bloom season that starts in June. Depending on the variety, they will still be putting on their summer color well into August or September. This group of hydrangeas bloom on new, current season’s growth, which means you prune in the early spring. The flowers are produced at the tips of the new growth. Supplemental moisture is all that will be needed for the summer color.
There are a number of varieties of panicle hydrangeas on the market and range in size from a few feet to 6 feet or more. Some of the tried and true varieties for our area include ‘Little Lamb,’ ‘Tardiva,’ ‘Pinky Winky,’ ‘Limelight,’ and ‘Quickfire.’ Newer varieties coming onto our local market are 'BoBo' and 'Phantom'. Once the peak bloom is past many of the flowers will fade to a nice chartreuse green. Its rusty fall color will provide interest well into the fall.
Rose of Sharon
Rose of Sharon, or Althea, is an old time favorite. Many of us can remember this summer shrub growing in Grandmother’s garden. What’s new is that breeding programs have now selected strains that are seedless and have improved flower color. One of the issues with the plant is it can be large. There is a simple fix to controlling size and that is to prune hard each spring. Rose of Sharon blooms on the new growth so a hard prune in the spring will reduce size but not decrease the floral impact.
Althea will flower best in full sun and will tolerate a little shade. Once established the plant is extremely drought tolerant. In fact, it could probably survive with no supplemental summer watering. Timely watering will improve growth and summer flowering.
Flower colors range from rich shades of white, purple, lavender, blues and pure whites, so there is something for just about anyone’s taste. Common varieties include ‘Aphrodite’ which is pink, ‘Minerva’ a shade of lavender, and ‘White Chiffon’ and ‘Diana’ that flower in white. New to the market this spring is ‘Blueberry Smoothie’, a bluish purple double flowering Althea.
A staple of the South, crape myrtles are now right at home in local gardens. This plant loves the heat and is in its prime during the dog days of summer. Crape myrtle will thrive in blazing hot sun and is highly drought tolerant.
Being a southern plant, this shrub can have problems with colder winter conditions. Oftentimes the growth will be killed back to the ground. But the good news is that the roots are hardy and new growth will appear. Like the other shrubs of summer, this plant also blooms on new growth, so if the plant does winter-kill the flowers will still appear.
Since the plant can dieback, one issue is gauging how tall the shrub will grow. There are numerous varieties on the market in a range of heights. A few good selections include: ‘Rhapsody in Pink’; ‘Siren Red’ and ‘Muskogee’, red; ‘Velma’s Royal Delight’, purple; and ‘Acoma’, white.
Let’s not forget the classic shrub of summer for Kansas City, the butterfly bush. This plant has long been a favorite for its range of flower color and ability to provide nectar for our butterflies. This plant is a cutback shrub and blooms on new growth. So treat it like the Caryopteris each spring.
What’s new in butterfly bushes are the number of newer varieties and flower colors. The Flutterby Series and Lo and Behold Series are smaller in size and offer nice shades of lavender, purple and pinks. ‘Miss Molly’ and ‘Miss Ruby’ offer more intense colors never seen before in butterfly bushes. So don’t overlook this standby plant as a source of color during the heat of summer.
There you have it, the shrubs to add a much needed splash of color to the landscape. By adding any of these selections to your landscape you will be sure to hit a home run, even a grand slam. These durable and heat loving plants will soon become an all-star performer in your garden.