Brian Minter: Perennial hibiscus have become a must have for midsummer displays

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They are big, bold and truly some of the most spectacular garden show-offs. Perennial hibiscus have been around for quite a few years, but with the recent addition of Proven Winners’ collection of Summerific giant flowering varieties, they have become a ‘must have’ for midsummer displays.

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Many growers and homeowners usually start the older varieties in early January from seed, and by late July, during hot weather when many other plants struggle, these tough hibiscus with six-to-seven-inch blooms look magnificent.

Kieft Seed in Holland was one of the first to develop the Luna series that includes a good selection of colours from the traditional red, rose and white with red eyes to the new Pink Swirl, with its shaded, picotee patterning. Growing about three feet in height, these plants are incredibly heat and drought tolerant and bloom for six to eight weeks. The Honeymoon series, with a similar range of colours and huge blossoms, is a little more compact and is ideal for containers.

In areas with a short summer season, the Disco Belle variety may be best because it matures and blooms in a shorter time frame. It still has those stunning, large blooms that also thrive in hot summer conditions.

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Walters Gardens in Michigan, one of North America’s premier perennial suppliers to the growing industry, has partnered with Proven Winners to produce some fantastic varieties of perennial hibiscus. They have branded them as the Summerific Collection. There are over 11 varieties in this series, and each one has something unique to offer in blossom colouring, foliage and blooming habit.

Walters’ hibiscus breeder, Hans Hansen, looked at several factors when he began breeding this special series. Native species were all tall, and blooms appeared only on the tips of the plant. Hansen tried to develop a more compact and rounded habit. Not only did he improve the flowering habit so that blooms appeared throughout the plant, but he also produced blooms measuring seven to nine inches across with overlapping petals for a more stunning appearance. Foliage was always important. So, Hansen worked on developing a rich bronze foliage that contrasted nicely with the blossoms.

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As a general rule, the flowers of older varieties of perennial hibiscus were at their prime for only one day, but Hansen was able to extend that up to two days. He was also working to create a tropical look to add a distinctive touch to summer gardens.

I contacted Jessica DeGraff, Proven Winners Retail Account Manager, for her perspective. She said Summerific Berry Awesome set a new standard for the Summerific series. Once established, it grows about four feet tall and wide, flowers from top to bottom with huge eight-inch, ruffled, rose coloured flowers, sports a red eye in the centre of each blossom and blooms from midsummer well into September. Its olive-coloured foliage offers a perfect contrast to the flowers.

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Summerific Holy Grail is in high demand because of its almost black foliage and contrasting deep red flowers. There is something quite striking about this combination of colours.

One of my favourites is Summerific Ballet Slippers with its ruffled, overlapping white petals, a red eye and blush-pink shading on the edges of each petal.

Summerific Cherry Choco Latte is as beautiful as its name suggests. Its nine-inch white blossoms, shaded with intense deep pink veins, are set off nicely by large red eyes and contrasting dark olive-green foliage. Summerific Spinderella is similar but with darker foliage that really packs a punch.

Summerific French Vanilla is a breakthrough because of its ruffled, soft yellow flowers which hold their colour in the heat. Its large red eye and contrasting deep green foliage make this a standout variety.

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Walters Gardens also have their own collection of varieties with great individual characteristics. I like their Starry Starry Night, with its pinwheel pink stripes, red eye and rich burgundy foliage. Midnight Marvel has nine-inch, cranberry red flowers contrasted by rich, dark, maple-like leaves.

Today, there’s a terrific selection of perennial hibiscus for home gardens. I’ve been told by hibiscus experts that for perennial hibiscus to perform at their highest level, they need the hottest spot in your garden. I asked DeGraff her thoughts and she concurred. In cooler, coastal areas, she said they will perform well if you can find them the warmest, sunniest spot.

“No question,” she stressed. “They are true heat lovers.”

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One curious thing about these hardy (zone 4) perennials is their late start in the garden. Many folks express concern about their viability because it’s often mid-June before they show any signs of being alive.

“Leave them be,” DeGraff reiterated. “They will come to life even if it’s late June.”

When perennial hibiscus produce new shoots, they grow very quickly up to four feet, and the plant will usually start blooming by mid to late July. Perennial hibiscus need plenty of water once they size up, and they love a feeding of slow-release fertilizer to keep them blooming well into early fall. DeGraff also pointed out that they are excellent pollinator plants.

When they lose their leaves in late fall, it’s best to cut them back to about eight inches above the ground. In wet areas, good drainage is also essential to prevent roots from rotting.

These giants should be available in many garden stores now. So, if your garden needs a little summer drama, pop in one of these summer giants, stand back, and watch the performance.