Hibiscus - 'Watermelon Ruffles'

Hardy hibiscus is the plant that stops traffic in August, and 'Watermelon Ruffles' is the one that does it with the most flower. The blooms are seven inches across — dinner-plate scale, the size of an outstretched hand — in a saturated watermelon pink that carries clear across a yard. What sets this one apart from every other big pink hibiscus is the petal itself. The margins are so heavily ruffled and notched that the flower reads as nearly double, a crumpled, layered thing more like crepe paper than the flat five-petaled pinwheel most rose mallows produce. It is among the most ruffled hardy hibiscus in the trade, and the texture is what makes it hold up at close range as well as it does from the road. The petals sit against dark green foliage with a bronze cast, which does the color a real favor: a hot pink flower needs a dark background or it goes shrill.

'Watermelon Ruffles' builds an upright, rounded, shrub-scale clump 4½' tall and 4½' wide — a substantial plant, and one that needs to be sited as a shrub rather than tucked into a perennial border as an afterthought. It is herbaceous, dying to the ground every winter and rebuilding that entire mass in a single season. Growth is remarkably fast once it starts, capable of adding an inch a day in warm weather. Foliage is dark green with a bronze cast, broad and maple-like, dense enough from the ground up that the plant works as a summer screen. It is one of the very last perennials to emerge in spring, and that trait deserves its own line in the care section below, because it is the single most common reason people think they have lost a hardy hibiscus.

Bloom. Flowering runs from midsummer into early fall — in the Ohio Valley, generally from mid-to-late July through September, with the indeterminate bud set pulling the start earlier than a conventional hardy hibiscus and stretching the finish later. Individual flowers are 7" across, watermelon to magenta pink, with heavily ruffled and notched petal margins that give a near-double appearance, and the prominent staminal column standing out from the center in the way all hibiscus flowers carry it. Each bloom opens for a day or two and closes; the show is a matter of succession, not persistence, and a mature plant will carry a great many buds at any given moment. Cool weather can slow bud production; heat does not bother it at all.

Full sun is the honest answer — six hours minimum, and more is better. It will grow in part shade with four to six hours, but bloom count falls off and stems stretch. Soil is where hardy hibiscus differs from most border perennials: this is a marsh plant by ancestry, and it wants consistent moisture. It tolerates poor to fertile ground, prefers a slightly acidic pH in the 5.5–6.2 range, and will handle wet feet and even seasonal standing water that would kill most perennials. What it will not tolerate is drying out — leaf scorch and bud drop follow drought quickly. Care difficulty is low, but it is low in a different way than a hellebore: this plant asks for water and food rather than being left alone. Heat and humidity tolerant, mildly salt tolerant, deer resistant. Hardy in USDA Zones 4–9.

Treat it as a flowering shrub that happens to disappear each winter. It anchors the back of a sunny border, stands alone as a specimen on a lawn, screens a utility area from July to frost, and is one of the few showy perennials that genuinely belongs at a pond edge, in a rain garden, or in the wet low spot where nothing else has worked. It is also a strong container thriller in a large pot, provided the pot is big enough to keep from drying out midday in August. Watermelon pink is a hot, high-chroma color and needs to be handled accordingly: it looks superb against chartreuse foliage, silver, deep burgundy, and the blue-greens of switchgrass and little bluestem, and it will fight with orange and brick red. Because the plant emerges so late, plant spring bulbs and early perennials over and around the crown — they will have finished and gone dormant by the time the hibiscus needs the room. Space plants 4½–5' apart, and give the clump enough elbow room that air moves through it.

How we ship Hibiscus - Rose Mallow

Hibiscus are planted in the spring and grown into sizable 3 gallon plants through one year. We sell them locally through the summer and fall, into the next spring, once we feel we've added good value to the size of the plant, we will ship them after one year of growth bare root until they emerge from dormancy. Hibiscus always emerge late so this gives us a spring window for online sales. You will receive the equivalent of a 3 gallon potted plant in a bag with moist material. It should be potted or planted within the first few days of receiving it.

Photo Credit: Walters Gardens and New Blooms Nursery

General care for any tree or shrub is easy, but like any living thing will require your attention. Please educate yourself and follow these simple rules.

Hibiscus - 'Watermelon Ruffles'

Caring for hibiscus is not difficult, but the plants do require some maintenance. Site selection is important, so plant in an area that receives lots of sun, but also will remain sufficiently moist. Keeping hibiscus well watered will result in the largest and fullest flowers and foliage. Occasional deadheading is recommended to keep the plant looking its best, but isn’t strictly necessary. It is best to plant hibiscus before the heat of summer arrives to give it time to establish and a thick layer of mulch is recommended to ensure soil moisture is maintained. As always, we recommend a hardwood mulch, because it is simply the best for retaining moisture and only improves as it is refreshed each year. Be aware that hibiscus is one of the last plants to arrive each year - so you’ll probably think it is dead and freak out a little bit, but be patient and your patience will be rewarded. Hibiscus is a target for Japanese beetles, since beetle numbers vary from year to year, be prepared to treat them or pick them off regularly.