© Janet Davis
July 2005
For the past few years, gardeners in cold
climates have been thinking up new ways to 
use the big, bold leaves and colourful blossoms of tropical species
as they design their outdoor planters and borders.
When I say “tropical”, I don’t mean impatiens, begonias and petunias -- for, of course, these old-fashioned bedding plants are also natives of steamy, equatorial climes. What I’m referring to are the Carmen Mirandas of the plant world: tall canna lilies with their brassy flowers and dramatic leaves; spiky, earth-toned phormiums with names like ‘Bronze Surfer’ and ‘Maori Sunset’ that hint at their common moniker, New Zealand flax; lush ornamental bananas with their purple blossoms and paddle-shaped leaves; blowsy hibiscus; bizarrely-marked crotons; and gorgeous Rex begonias like ‘Miami Storm’ with leaves splashed in fuchsia and silver.
Then there are the taros and elephant ears
(colocasias and alocasias) with their fondness for swampy soil and their giant,
wavy-edged leaves in hues from chartreuse to ebony – perfect for lending a
tropical feel to the edge of a pond.
And blue-flowered plumbago, yellow allamanda, orange 
lantana and shocking pink bougainvillea that some might recall from
Caribbean holidays, now spilling happily out of deck planters in chilly parts
of North America.
The surging interest in tropicals is, like all new trends, a product of boredom and business opportunity. The boredom of gardeners needing something new to keep the creative juices flowing and business opportunity for nimble-footed plant breeders and nurserymen anxious to cash in before the rest catch up. So while there are still umpteen types of impatiens and petunias on the market, there are now literally thousands of cultivars of coleus too. That’s a good thing, of course, because the sensuous foliage of coleus offers as much variation and colour as traditional flowering annuals, but there’s no need for time-consuming deadheading.
While on New York’s Long Island for a gardening
symposium last September, I saw tropicals used in wildly imaginative ways. At Landcraft Environments in Mattituck,
owners Bill Smith and Dennis Schrader 
(author of Hot Plants for Cool Climates) launched their
wholesale tropical business in 1992 out of frustration at finding exciting
summer plants for their tony Hamptons clients.
In their own annual borders, I liked the way they mixed tall and unusual
Japanese silver-leaf sunflowers (Helianthus argophyllus) with striped
green ‘Pretoria’ and red ‘Tropicanna’ cannas, then fronted the whole thing with
red coleus, orange nasturtiums, ‘Profusion Orange Zinnias’ and golden lantana. At mid-border were the striking, burnt-orange flower spikes of
‘Hot Biscuits’ prince’s feather (Amaranthus hypochondriacus), a grain
amaranth that’s being used increasingly as a flamboyant ornamental.
On the campus of Farmingdale University, where horticulturist Richard Iversen
(author of The Exotic Garden) creates a series of stunningly creative,
outdoor, tropical gardens each summer,
I saw bronze-splotched banana leaves mixed with mocha-brown phormiums,
red-and-yellow ‘Lucifer’ cannas and standard-issue red salvia (looking
drop-dead gorgeous in that fine company).
And finally, at the New York Botanical Garden, I was blown away by a series of huge pots filled with small palms and tropicals like copperleaf (Acalphya wilkesiana) with its floppy brown-and-pink leaves; dark-red cannas; coleus in rust, orange and wine; burgundy cordylines; lime-green ‘Margarita’ sweet potato vine; orange-flowered tropical milkweed (Asclepias curassavica); and dark-leafed Hibiscus acetosella ‘Maple Sugar’. The pots were lined up outside the conservatory – a reminder that a bright sunroom or fluorescent light set-up is the necessary destination when the cold winds of a northern autumn blow and expensive tropicals must be either ferried indoors or consigned to the compost heap.
Adapted from a story that appeared in the National Post