Forget the fussy tropical hibiscus houseplants for summer color…. instead plant the tough, hardy, perennial hibiscus with flowers up to 12 inches across! Especially if you live in areas where winters are freezing, the hardy hibiscus makes more sense. Hardy hibiscus starts slowly in mid-summer and then explodes with colorful crepey blooms in late summer. In a perennial bed, in early spring you can see the dead stubs that are left over from last year mark the spot where the beautiful flowers will appear in August. Worth waiting for, the dinner plate sized flowers last only a day, but like daylilies, produce a succession of blowsy, vibrant blooms that can cover the plant.
Coming in reds, whites, pinks, and lavenders, hibiscus is part of a confusing group of plants with many common names-hibiscus, rose mallow, althea, rose of sharon, giant mallow, swamp mallow, among others. Growing as far north as Zone 4, the genus hibiscus has both tropical and non-tropical species and is the state flower of Hawaii.
If you live in Florida or Hawaii, you can enjoy these wonderful flowers all year round with the tropical species coming in yellows, oranges, and other wild colors. Frilly, doubles, bi-colors, variegated foliage, tropicals need the full sun to bloom their best.
Tropical Hibiscus ‘Fifth Dimension’ is one of my favorites. Emerging in the morning an orange/bronze color, as the day progresses, it morphs to yellow and silver. You can see a time-lapse of this process at Longwood Gardens.
Longwood Gardens is where I see the most fabulous tropical hibiscus ever. But they have the greenhouses for overwintering these beauties.
The Hardy Hybrids
I am more interested in the hardy hybrids, which I call ‘yard shrubs’, that are winter-hardy and display their fabulous flowers all summer into fall. Deer tend to leave them alone also, which is an added bonus.
The Hibiscus syriacus or ‘Rose of Sharon’ hardy ones are very familiar to people as an old-fashioned shrub. Finding these shrubs in older homes is common, but many new cultivars are coming out with different colors, double blooms and larger ones.
Easy to grow in full sun or partial shade, the hibiscus clump will put on a huge show for about a month and then will pop out bunches of flowers for several succeeding weeks.
I cut the shrubs stems back in late winter or early spring and wait for the spring shoots to start appearing. Because hardy hibiscus appears so late, this is the perfect shrub to plant spring bulbs and early annuals nearby to fill in the opening. Once the early spring flowers are done and gone, the hibiscus is putting on good growth and will shoot up quickly.