This has been the year of the hibiscus at The Garden Guy's house. The tropical selections like South Pacific Sipper, Monsoon Mixer, Hawaiian Big Kahuna, and Fiesta. The past few weeks it is the Holy Grail a hardy hibiscus that you simply can't take your eyes off. Holy Grail is part of Proven Winner's Summerific series. There are a total of 8 colors in the series with Berry Awesome also acclaimed.
Typically, a tropical hibiscus, Hibiscus rosa-sinensis, has glossy leaves and the perennial types, rose mallow hybrids are flat. 'Holy Grail' has dark green foliage that has been aging to purple. In promotional photos, the images show very deep or dark purple leaves. My area is a little sunlight challenged so I'm not sure if mine will reach that level of purple or not.
The blooms are deep red, darker in the center and reach 8- to 9-inches across. As true with other hibiscus blooms only last a day. On day two, however, you are left with a bight chartreuse star-shaped calyx. Expect your plants to reach 4- to 5-feet tall, and as wide. It is a profuse bloomer as every flush growth gives dozens of more bloom. I have three, and in all locations, they are dynamic; doing great in any soil type.
The last few years, there has been a multitude of new, hardy hibiscus, not only hitting the market but winning awards, too. When you look at a tropical hibiscus blooming on your deck or patio, it is easy to conjure up visions of the Caribbean and the sounds of a steel band. Today's perennial hibiscus varieties will do the same.
Think about how you can use perennial hibiscus in the tropical landscape. Create an exotic look with large bananas growing behind one of these shrubs, or plant a yellow bush form allamanda as a perfect companion. Hibiscuses belong in the landscape whether combined with bananas, cannas, or another tropical plant.
In my garden, I am using them as the backdrop to a habitat of pollinators. Perennial hibiscus will bring in bees, butterflies, and hummingbirds and one of the best traits is, they are resistant to deer. So, my companions are various salvias, Agastache or anise hyssop, coreopsis, and rudbeckias.
Their requirements are much like those of other annuals. Whether you choose the perennial or tropical types, plant in well-drained, well-prepared beds and use a good layer of mulch to keep the soil evenly moist through the season. Drying out during bloom season leads to unhappy results.
When I say hardy hibiscus, I mean they will be perennial from zones 4-9 which means most of the country can relish in their beauty. Choose a site with plenty of sunlight. Morning sun and filtered afternoon light are just about perfect. The hibiscus blooms on new growth, so it is important to keep it growing vigorously throughout the season. Keep them well-fed and watered during droughty periods.
You will not need a super-bloom fertilizer however, just use a slow-release, balanced fertilizer applied in regular small monthly applications. Water daily during the summer if you are growing Holy Grail or any other perennial hibiscus in containers. Nutrients will quickly leach from the soil, so apply a dilute, water-soluble fertilizer weekly or add controlled release granules per label recommendation.
Summerific Holy Grail will steal the show in your summer garden, but you won't need the law enforcement. Just know that your friends and visitors may stay a little longer gawking at the beauty of the flowers.
(Norman Winter, horticulturist, garden speaker and author of, "Tough-as-Nails Flowers for the South" and "Captivating Combinations: Color and Style in the Garden." Follow him on Facebook @NormanWinterTheGardenGuy.)