American Nurseryman Magazine - Horticulture Magazine and Horticulture Books - Blurring the Lines - August, 2014 - FEATURES

American Nurseryman Magazine - Horticulture Magazine and Horticulture Books - August, 2014

FEATURES

Blurring the Lines

With home gardeners pushing the boundaries and the climate chnage altering hardiness zones, we take a look at some popular temperennials-those warm-zone perennials that are steadily making their way Up North.
By Sally Benson


Photos courtesy of Sally Benson

Looking for an out-of-zone experience? So are your customers. Following last winter's Polar Vortex, gardeners in the North were desperate for any sign of life, and once the weather finally cooperated, annuals, perennials and woody plants filled their carts and gardens. There's another category, though, that has quietly become the must-haves for anyone willing to try them.

They're tropicals, they're warm-zone plants - they're temperennials (see sidebar). And they're being grown, sold and planted far north of their designated hardiness zones. The phenomenon isn't new; plant professionals and brave gardeners have been pushing the boundaries for years.

Whether they're treated as annuals and tossed after the season wanes or brought inside to a greenhouse or a sunny windowsill, tender perennials have a sneaky way of winning customers' favor. And from big and blowsy to short and sweet, there's a variety out there that will favor your bottom line.

We've highlighted just a few here, but there are hundreds of possibilities. So when you're planning next season's growing program or ordering for the spring rush, think outside the zone.

Sally Benson is the editorial director of American Nurseryman. She can be reached at sbenson@mooserivermedia.com.

Begonia 'Gryphon'

This unusual begonia grows large enough to fill an oversized container and serve as a summertime shrub. The unique, dark green leaves-frosted with silvery white-stand atop prolific, sturdy, 12- to 16-inch long stems that form a rounded, mounding habit reaching to nearly 2 feet wide. It requires little water and performs for months on end. Hardy in zones 9 to 11.

Coleus species

There are so many colors and shapes and sizes and forms that it's hard to know where to begin. Coleus is known for its dramatic and varied colors and patterns; there's a selection here for everyone. It's well-suited to containers, but used in a border, many varieties fill in and act as brilliantly colored shrubs-no deadheading required, although some of us snap off the flower spikes in favor of fuller foliage. Hardy in zones 10 to 11.

Colocasia species

Oversized, heart-shaped leaves nod atop very sturdy, arching stems that often reach 4 feet tall in northern climes-in a subtle breeze, the leaves seem to be gently shaking their heads. A strong, central vein bisects each leaf, whose colors range from deep plum (nearly black) to splotched and spotted to light green with purple venation. Colocasia adds a true tropical look to the Northern landscape. Hardy in zones 8(9) to 11.

Cordyline australis

Strong and bold, the reddish, swordlike foliage of Cordyline australis punctuates the Northern garden and provides architectural interest. In Northern zones, it can reach nearly 4 to 5 feet tall and does well in border, beds and in mixed container plantings. Drought tolerant. Hardy in zones 9 to 10.

Kalanchoe species

Often grown as a houseplant in Northern regions, this flowering succulent has gained popularity as a container selection on decks and patios. There are more than 100 species, but Kalanchoe blossfeldiana is among the most popular. Long-lasting, large umbels of flowers ranging from scarlet to pink, salmon, yellow and white are held above scalloped leaves. Hardy in zones 10 to 12.

Pennisetum setaceum 'Rubrum'

Sporting bronze to dark purple foliage, this outstanding fountain grass has found a home in the garden as well as in containers. Growing to about 3 feet tall, the foxtail inflorescences emerge dark red in mid-summer, then slowly fade to a buff tone that can last beyond the first frost. Hardy in zones 8 to 11.

Salvia guaranitica 'Black and Blue'

This is a particular favorite, one that graces at least three or four containers each season. It attracts butterflies, bees and-best of all-hummingbirds, who often ignore the feeders in favor of this sage's intense, cobalt blue, hooded flowers. Although the cultivar name may be a bit offputting at first, it describes the dark stems and buds, which emerge nearly black. Against the lime-green foliage, these colors pop, especially when the blossoms dance above the full, vigorous plant. Hardy in zones 8 to 11.

What's a "temperennial"?

The term "temperennial" was developed by noted plantsman Pierre Bennerup, chairman and CEO of Sunny Border Nurseries in Connecticut, back in 2003. Bennerup was looking for an appropriate way to describe plants that are true perennials in warmer hardiness zones - tropical climates, if you will - but are grown and used as annuals in colder regions. Hardy down South, less so up North, they're tender perennials.

Bennerup trademarked the Temperennial™ brand, and Sunny Border Nurseries offers a line called Bodacious Temperennials™. This year's catalog is packed with more than 40 pages of alluring plants ranging from Abelmochus to Zinnia and includes succulents from Aeonium to Senecio.

The term has been added to the horticultural lexicon over the years and has come to mean those tender perennials that won't overwinter without protection in the Great Frozen North, but are so irresistible they can't be ignored.