Laughing at the dog days of August

Perennial hibiscus shines in hot weather.


Particularly in hot climates, August tends to be a month when few flowers -- beyond annuals -- are putting on much of a show in the garden. But it doesn't have to be that way. There may not be as many perennials and shrubs that shine during the dog days of August as are at their peak in June, but there are some.

One of the best, in my opinion, is perennial hibiscus, also known as hardy hibiscus (hybrids of Hibiscus moscheutos). For some reason, it isn't nearly as widespread as tropical hibiscus, which is killed by frost come cold weather, or as the shrub known as rose of Sharon.

Perennial hibiscus, as its name implies, dies to the ground each winter and returns each spring. Some cultivars are ideal for small gardens. Others mimic the height of rose of Sharon, really making an impact at the back of the perennial border. Not just because they're six to eight tall, but also because the flowers are real showstoppers.

Most are huge. Expect 10-inch blooms on many cultivars, up to 12 inches on Crimson Walker. All have gorgeous colors. There are even varieties of perennial hibiscus that are perfect for small gardens and containers: Disco Belle and Southern Belle produce large flowers on plants that stay about three feet tall.

Except for the native Hibiscus coccineus (swamp hibiscus), which is rated for Zone 7, most perennial hibiscus are reliable to at least in Zone 6. (They grow well here in Boston, for instance.) But by mulching them well over winter, Zone 5 gardeners should be successful, too.

Place perennial hibiscus in a spot with full sun and well-drained soil. It's a thirsty plant and will need water when rainfall doesn't arrive regularly during the growing season.

It's also a good idea to fertilize them several times during the growing season.

Unfortunately, if you live in an area that's been invaded by Japanese beetles, these pests love hardy hibiscus as much as gardeners do. (The one exception: Hibiscus coccineus.) Sigh.

But mostly they're trouble-free. If you place a few perennial hibiscus plants in various parts of your yard next spring, you'll ever again have a drab yard in August.

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