If you’re looking for summer flower power, look no further than hardy hibiscus.
This plant has it all:
- Awesome summer-long flower show.
- Flowers the size of dinner plates.
- Hardiness from Florida to Canada.
- Adaptability to a wide range of soils.
- Fast growth.It’s a native.
- It’s even resistant to deer browsing
It’s the kind of crop growers like to produce because it’s so fast. It’s a plant retailers like to sell because it almost jumps off the shelves when in flower. And it’s a plant gardeners love to grow because it’s foolproof, tough as nails and reliable. In fact, this is the kind of plant that any budding gardener can grow successfully, giving them confidence to move on and try other species. What’s not to like?
Hibiscus moscheutos and other native species are parents of the cultivated hardy hibiscus, also known as perennial hibiscus or rose mallow. A cousin of okra and cotton, hardy hibiscus is also closely related to tropical hibiscus, confederate rose, and Rose-of-Sharon.
Unlike its woodier relatives, hardy hibiscus is a herbaceous perennial producing multiple cane-like shoots that emerge in late spring, flower in summer and die back with autumn frost.
Hardy hibiscus requires the long days of summer to initiate flowers. Buds form in leaf axils near branch tips and open into the exotic-looking flowers typical of hibiscus, each with five petals surrounding a prominent pistil. Flowers last just one day, but so many buds form that the plant appears perpetually in flower throughout summer and fall until frost.
Easy to produce
Hardy hibiscus is on the ever-growing list of “crossover” crops produced by greenhouse growers and traditional outdoor nursery growers. Finished plants can be produced from seed, plugs or cuttings in eight to 14 weeks, depending on liner size, growing conditions, time of year and cultivar.
Standard procedures will suffice, with only high light and high temperatures needed for fast growth. Long days are required for flower bud development. Although hibiscus is considered a heavy feeder, frequency of fertilization matters more than amount. Over-fertilized plants will grow too large and not flower well, whereas nutrient-deficient leaves will turn yellow.
Uniform soil moisture is necessary, too. Plants allowed to wilt respond with leaf yellowing and leaf drop (reducing plant quality) and produce fewer flower buds. Keep plants jammed pot tight until canopies of neighboring plants touch, then space to reduce stretch. This allows the development of bushy, compact plants. Some growers use plant growth regulators on hardy hibiscus. But these products — and pinching or pruning — are less important on newer, self-branching cultivars.
Packs a punch
Hardy hibiscus is one of the most gratifying plants a gardener can grow. Few other perennials provide as much bang for the buck in terms of flower size, length of flowering and ease of care. Hardy hibiscus grows best with full sun in rich, moist soil but tolerates even the poorest, sandiest soil if mulched and watered once in a while.
Flowering is promoted by plentiful rain and sunshine. No matter how much and how often you irrigate a landscape, nothing beats good rain when it comes to stimulating flowering.
Hardy hibiscus is cold hardy from USDA Hardiness Zone 9-4. Plant emergence and subsequent flowering begins in late spring in the lower South and occurs progressively later moving north, with flowering in late summer in the northern United States and Canada.
As with many perennials, some hardy hibiscus won’t return after winter dormancy, especially some of the newer, more refined cultivars. Still, most plants return year after year, and hardy hibiscus gets better with time. Older plants tend to emerge sooner in spring, grow larger, flower sooner and produce larger flowers than young plants.
Hardy hibiscus is fairly pest resistant. While an array of minor pests can attack plants, the most devastating pest is the larvae of hibiscus sawfly. This pale-green caterpillar like larvae is gregarious, meaning several often feed on the same leaf or plant. It can quickly defoliate entire plants.
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