Regional Gardening Reports :: National Gardening Association

In the Garden:
Upper South
August, 2012
Regional Report

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Try hydrangea Vanilla Strawberry and other shrubs for weeks of summer garden color. Photo courtesy Bailey Nurseries.

More Flowers -- Easy as One, Two, Three

Do you wonder why your garden isn't filled right now with lots of flowers? Books, magazines, and web sites certainly show us photo after photo of gardens overflowing with flowers. Descriptions of long-blooming perennials say that they bloom from June until frost. But what is the reality? Many a late summer garden is more likely will offer us shades of green rather than a riot of color.

Heat and drought notwithstanding, except for a few late blooming types, daylilies are just a memory. The earliest blooming hydrangeas now have dried flower heads. The dinner-plate blooms of hibiscus are winding down. Even those summer stalwarts, rudbeckias and echinaceas, are only sporting a few bedraggled flowers, depending on whether you've been watering or not.

Certainly, we'll soon have the glorious and colorful flowers of asters and mums, but are there plants that will fill our gardens with blooms from mid to late summer? Three shrubs are the stars of this interim season -- panicle hydrangea, crapemyrtle, and rose-of-Sharon. Each is easy to grow and provides weeks of color.

Panicle Hydrangea
Hydrangeas in general have become one of the darlings of the garden, with many new varieties for each of the species. For years, the sole star in the firmament of Hydrangea paniculata was 'Grandiflora', commonly known as the PeeGee hydrangea. Gardens in decades past would often have a single PeeGee grown as a standard. Today, we're more likely to see other varieties massed along a fence line or in a shrub border. Of the newer varieties, Limelight, with its appropriately lime green flowers, has become one of the stars. Growing to 8 feet tall, this is not for smaller gardens, but Little Lime, growing only 3 to 5 feet tall, may be a better choice. Other popular varieties include Phantom, Pinky-Winky, Silver Dollar, Vanilla Strawberry, Bobo, and Kyushu. One of the highest rated in various trials is Big Ben.

Tree and shrub specialist Michael Dirr has described panicle hydrangeas as "difficult to kill." That said, for best growth, aim for moist, well-drained soil in sun or partial shade. In late winter or early spring, prune these hydrangeas, either almost all the way to the ground (leaving two growth buds), more moderately to four buds, or just removing last year's flower heads. The amount of pruning generally determines the number of flowers and time of blooming.

Some people accuse Southern gardeners of overusing crapemyrtle, Lagerstroemia species and varieties, but in our region, it has barely gained a toe hold and deserves to be much more widely planted, especially since there are many new varieties that are hardier than previously available and in a range of mature plant sizes. One of the most stunning garden combinations I've seen this year uses Knockout roses with a crapemyrtle with flowers in the same color. Unfortunately, the homeowner didn't know the variety, but this is a combination worth searching out.

The United States National Arboretum (USNA) has been very involved in developing many of the newer varieties. Their advice for selecting a crapemyrtle is to first think about flower color and ultimate size. Flower colors include magenta, red, red-orange, violet, pink, and white. Sizes range from 3 feet to 20 feet or more. For more information about the crapemyrtles developed by USNA, go to their Crapemyrtle Quick Quide Chart at

Crapemytles thrive in summer sun and heat, growing in any reasonably good, well-drained soil with a slightly acid pH. Even if the top growth of a crape myrtle is killed, simply cut the plant back to healthy wood. They'll still bloom, as crapemyrtles flower on the current season's growth.

Rose-of-Sharon, Hibiscus syriacus, is an old-fashioned garden staple that is one of my favorite plants, with one caveat. The older varieties were notorious for re-seeding about the garden. Newer varieties are sterile, so we can enjoy the weeks of flowers without the dread of pulling seedlings. Again, the United States National Arboretum is responsible for some of the best of these. Minerva, with lavender flowers and a dark red eye; Helene, with ruffled white flowers centered with red; Aphrodite, with ruffled pink flowers centered with red, and Diana, with pure white flowers, deserve to be in every garden. They usually grow 8 to 10 feet tall and 7 to 8 feet wide.

Two varieties introduced by Proven Winners are also great garden additions without the risk of seedlings. Li'l Kim has white flowers centered with a red eye. Although said to be a dwarf form growing only to 3 or 4 feet, mine are closer to 8 feet tall, but narrow growing. For fans of variegated foliage, Sugar Tips delights with creamy white and bluish-green foliage. Plants produce quantities of pale pink double flowers. Plants grow 8 to 12 feet tall and 4 to 6 feet wide.

It shouldn't be surprising that rose-of-Sharons are not picky as to soil as long as it is well drained. Flowering is heaviest and growth more compact when grown in full sun, but they will tolerate light shade.

Add some of these shrubs to your garden later this fall or next spring so that you'll have a garden filled with flowers from mid to late summer for many years to come.

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