The tropical hibiscus produces some of the most lurid blossoms in the garden - a broad, ruffled, flared collar around a central antenna full of knobbly, nectar-rich protuberances.
The flower seems to embody some sinful, Gauguinesque escape to the tropics. So why haven’t we all got them?
They remain reasonably popular, especially among newer gardeners who have yet to discover the rewards of subtlety, but the tropical hibiscus can break your heart. There is a price for its voluptuary nature: Hibiscus rosa-sinensis is demanding of water and food, pest-prone, and difficult to overwinter indoors.
I have embraced other tropicals that I might have once considered over the top - banana plants, elephants ears, cannas, even coleus, but for the tropical hibiscus, I can’t quite shake the image of it being used to create instant effects in tiki bars and around hotel swimming pools.
If you are unburdened by such associations, if you are up to the challenge of keeping it or are happy to trash the thing at the end of the growing season (a valid tack), then grab one by all means. There is still enough of the growing season ahead of us in the Mid-Atlantic to warrant it, and there are lots of choices.
You can find them at the box store, in garden centers and online houseplant vendors. I would look for named varieties with superior traits such as more bushiness and flowering stamina.
A few years ago, a friend showed me his potted hibiscus; the petals were a copper brown. I thought he had forgotten to deadhead a faded flower until he said that was its peak display and wasn’t it marvelous? I remained quiet but regarded it as the worst thing since sliced bread. Alas, this grotesque became a trailblazer for a whole class of “fancy” hibiscus that seem to outdo themselves in terms of unnatural hues, jarring color combos and sheer weirdness.
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My view is that if you’re going to have a plant as hotblooded as a tropical hibiscus, you need to keep it under a tight optical rein.
If you don’t want it to clash with your Hawaiian shirt, go for some of the deeper reds, quieter pinks, softer yellows, etc.
Justin Hancock, horticulturist at Costa Farms, a major grower of houseplants and tropicals, said one of his favorites is Boreas White, a creamy hibiscus with a magenta eye that gives the flower depth. It is compact and floriferous. “The number of flowers it produces is really impressive compared to old school white hibiscus varieties,” he said.
I am drawn to another variety by the same Danish breeder - Graff Breeding - named Petit Orange. Images show it to be a small bush with handsome dark foliage and orange flowers about half the size of the grossest hibiscus but covered in blooms. This is the tropical hibiscus for me.
Before turning to shrinking the hibiscus, the company’s breeders worked on doubling flower life, now to a week or more, and keeping the blooms open after dark (they like to curl up for the night). Petit Orange is one of a new series of diminutive varieties, trademarked HibisQs Petit. They are not available in the United States - yet.
The plants currently are in quarantine and then will be evaluated for performance before a decision is made about bringing them to market here, said Hancock.
Growing tropical hibiscus can be challenging. They need an open sunny site to keep the flowers coming, but they are thirsty and may need watering every day in high summer - perhaps twice a day if confined to a container. Producing such enormous flowers takes it out of them, and they need regular but not excessive fertilizing.
They draw spider mites and aphids, both dealt with by hosing off the plant regularly, especially the undersides of the leaves. The more tenacious pest is whitefly, and the options for dealing with this range from biological controls that include ordering parasitic wasps to heavy-duty systemic pesticides, with the risk of harm to beneficial insects.
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A middle ground might be to spray with insecticidal soap or neem oil. The key with whitefly - whether on your hibiscus or Brussels sprouts - is to eradicate it early before the numbers build.
If you are overwintering indoors, it is important to get hibiscus plants as clean of pests as possible before bringing them in. Mealy bugs can be a real problem, not just for the afflicted plant but for neighboring, healthy houseplants. A badly infested hibiscus should be thrown out.
If you have an airy, humid, climate-controlled greenhouse conservatory, you can keep the hibiscus in flowering vigor all winter, but most of us don’t. In dark rooms, often way too dry, they go into a sort of leaf-dropping torpor.
Hancock recommends cutting back the plant by a third or so before bringing it indoors. There will be immediate leaf drop, but winter leaves will grow to be better adapted to the darker conditions. You then cut back on watering and feeding. The object “is survival rather than a show-worthy plant,” he said.
Put it out in the spring once nighttime temperatures reach the mid-50s or higher. It might need root pruning and re-potting then.
At this time of year, the challenge is to prevent it from drying out. If you’re going on vacation, “get somebody to water it for you,” said Nate Roehrich, greenhouse production manager at Brookside Gardens in Wheaton, Md. He prefers another species of tender hibiscus, the fragrant white hibiscus (Hibiscus arnottianus). The flowers are large but more delicate in their architecture, though the stamen is a confection of pollen-bearing needles. Finding it might be difficult, but at least you won’t have to drape it if your garden visitors are of a delicate disposition.
Remove the aging blooms of annuals and perennials to encourage reflowering and to prevent unwanted seeding. The deadheading will freshen the appearance of the plant as well. Leave seedheads to develop on sunflowers, coneflowers, rudbeckias and other composites to draw goldfinches and other seed feeders.