The last week in August is time to harvest squash, tomatoes and beans, cut back perennials such as daisies and daylilies that have past their prime and continue to water and fertilize potted plants and annuals in the garden.
This is also the time to celebrate the shrubs that offer late summer color.
Hardy Hibiscus or Rose of Sharon
Hibiscus is an old fashioned favorite that is enjoying a new popularity due to the improvement in hardiness and the size of the blooms. August is when this heat tolerant shrub puts on a spectacular show of color just when the rest of the garden may be winding down for the season.
Your grandmother probably called this shrub the Rose of Sharon but nurseries now know it as Hibiscus moecheutos or perennial hibiscus. The compact Luna series grows just 3 feet tall with huge blooms that can be six inches wide. The Disco series of hardy hibiscus grows even more compact at two feet tall and is perfect for patio pots. These shrubby dwarf hibiscus plants will survive our winters in Western Washington.
There is also a tall shrub form of hardy hibiscus or hibiscus mutabilis called the Confederate Rose in the south. This shrub can become a small tree and in my garden it has survived the wind and cold of Enumclaw for more than 20 years and has grown to 15 feet tall and 8 feet wide.
I grow a purple clematis through the branches of this huge hibiscus so that the white and red hibiscus blooms can co-mingle with the violet blooms of the Etoile Violette clematis. The garden gossip about all the hardy hibiscus is how naked this plant can be for six months out of the year. It will be the first of your shrubs to drop leaves in the fall and the last to sprout new foliage in the spring, sometimes waiting until May to show signs of life. Allowing a vine like clematis to use hibiscus as a lattice helps to clothe these bare branches in spring.
These are the hydrangeas native to the Eastern United States from north to New York and South to Florida. This means they can handle the cold and the heat better than the more traditional big leaf hydrangea macrophylla that have blue balls of bloom.
The Smooth hydrangeas have smaller leaves that are a gray green color and some varieties like the creamy white ‘Incrediball’ and the ‘Annabelle’ hybrids have gigantic blooms that can be one foot wide and have held up better in hot weather than other hydrangeas, but you need to prune these shrubs in early spring to keep the stems short enough to support the super-size flowers.
There is also a variety of smooth hydrangea that always flowers in the pink no matter how acid the soil. The Invicibelle Spirit II is an adaptable native shrub with blooms that not only look great at the end of summer and into the autumn season but also can be snipped for long lasting cut flowers. A Proven Winners award plant, when you buy the Invicibelle Spirit smooth hydrangeas there is $1 from every plant sold donated to the Breast Cancer Research foundation.
These small leaf maples from Japan are called Acer palmatum to describe the palm-shaped leaves with five separate lobes. Many choices in leaf color, growth habit and foliage texture make the Japanese Maple one of the most beloved plants to use in Western Washington landscapes.
Near the end of August when many plants are looking tired and seedy, the Japanese maples will be starting to color up and put on their annual fall show. This is the month to search out the most attractive varieties and shapes for a new or newly improved landscape.
If you plant a Japanese maple near ornamental grasses or sedum ‘Autumn Joy’ you’ll have a late summer display that will look great into the fall season even if you forget to water.