That’s where cold-hardy tropical plants can come to the rescue.
It may sound like an oxymoron, but cold-hardy tropicals really do exist. According to Byron Martin, co-owner of Logee’s Tropical Plants (www.logees.com), there are several varieties of plants that are thought of as “tropical” that can easily survive USDA Zone 5 and 6 winters.
“Tropical plants can give a garden a unique look and feel,” Martin says. “Cold-hardy tropical plants offer visual interest and variety with the added benefit of being tolerant of most winter climates. There is nothing quite as wonderful as introducing the large leaves, vibrant flowers and delicious fruits of tropical plants into a North American garden.”
Martin’s list of must-have cold-hardy tropical plants for American gardens includes the seven plants described below. “Don’t be afraid to plant something new,” encourages Martin. “It’s time to go beyond petunias and mums.”
Passiflora incarnata ‘Maypop’
Passion Flowers are delightfully exotic, with showy flowers that nearly shout out their tropical heritage. But ‘Maypop’ Passion Flower is actually native to North America, and it can handle a tough Zone 5 winter and come back strong the next spring. Like all Passion Flowers, ‘Maypop’ is easy-to-grow, and its vining habit can be trained to cover a trellis or climb up a fence or pole. Delightfully fragrant, 3-inch wide flowers with creamy pinkish lavender petals in a fully banded corolla appear throughout the summer. The flowers develop into succulent fruit. This is the hardiest of the Passion Flowers, growing successfully as far north as New England.
Musa basjoo (Hardy Banana)
Imagine growing tropical bananas in your outdoor garden in Chicago or Philadelphia or Kansas City – or even as far north as New England (Zone 4!). With this Hardy Banana you’ll get a defining tropical look. And, yes, with proper mulching, this tough plant can withstand temperatures below zero. This extremely vigorous banana grows several feet tall in a single season and in time forms large clumps that can reach up to 13 feet in height. Also known as the Japanese Fiber Banana, Musa basjoo makes a fine container specimen. If grown inside, it is easy to grow and will tolerate varying conditions of temperature and light with ease. Although it does produce bananas, they are not edible. Simple to grow, give it plenty of water, fertilizer and sunlight.
Gardenia jasminoides ‘Frostproof’
A cold-hardy gardenia that is also deer-proof sounds like a gardener’s dream come true. ‘Frostproof’ is a prolific bloomer of fragrant, pinwheel-shaped 3-inch flowers. Easy-to-grow and bloom, this new cultivar has a distinctive cup in the middle of the blossom, and the blooming season lasts from spring to fall. The plant has a nice symmetrical upright form with very attractive narrow green foliage that is about half the size of standard gardenia leaves. ‘Frostproof’ can be maintained at acompact 12-14 inches tall in a pot, but grows to about 3 feet tall outdoors. It requires moist, somewhat acidic, soil and full to partial sun. As the name implies, it is more tolerant of early frosts. Hardy to zone 6.
Clerodendrum bungeii (Rose Glory Bower)
This hardy Clerodendrum bungei with its flamboyant large umbels of rose-pink flowers can be grown inside as a potted showpiece or outside in your summer garden. The fragrant flowers appear spring through fall. Vigorous and easy-to-grow, the semi-herbaceous shrub has large, deep-green leaves and intricate pink globe-like flowers. The plant often dies back to the ground in winter, but comes back strongly in spring. In fact, the underground root system is invasive so the plant will spread unless kept in check. Prune when it gets too large and it will come back to fullness. Mulch in winter for Zone 6 hardiness.
Jasminum officinale (Hardy Jasmine)
This reliable and hardy species adds a sweet and enchanting fragrance to any outdoor garden. For a stellar performance, this vigorous climber needs a cold period to initiate bloom. Hardy to Zone 6 in a sheltered spot, the cold of winter brings this deciduous vine into a constant flow of sweet fragrant flowers right through the growing season. This is not a plant for a warm sunny window or a warm greenhouse, as it needs cold night temperatures down to freezing and below to realize its full potential. Hardy jasmine is a perfect plant to grow near a home’s entryway, so you can breathe in the heavenly scent of jasmine from late spring to fall.
Ficus carica ‘Chicago Hardy’
This edible fig can take sub freezing temperatures die back in the fall and re-sprout in the spring. The medium sized fruit ripens to a delicious sweetened in late summer and early fall. Also known as ‘Bensonhurst Purple,’ this tough, easy-to-grow plant traces its origins back to Sicily. It is officially cold hardy to Zone 6, although some Zone 5 gardeners have successfully grown it, too. For northern growers, mulch this plant heavily with hay or leaves when dormant. Ficus carica is also an excellent container plant.
Passiflora caerula ‘Clear Sky’
Passion Flowers are so delightfully distinctive and make such a major “tropical” statement that Byron Martin simply had to include two Passion Flowers on his list of cold-hardy favorite plants. Passiflora caerula is a famous Passion Flower species, but ‘Clear Sky’ is an improvement upon the original. This variety shows greater vigor than the standard caerulea and the flowers are an inch larger and much heavier in appearance. Each of the beautiful flowers carries a pristine clear light-blue color around the corolla. And, of course, it has the delightful fragrance of Passion Flowers, and the same vining habit. ‘Clear Sky’ is a tetraploid hybrid created by Roland Fischer of Hemer, Germany. It is not as cold hardy as Passiflora incarnata ‘Maypop,’ but it can easily survive a Zone 7 winter (and probably colder in a protected spot).
For more than 100 years, Logee’s has been offering exotic plants for indoor and outdoor growing. The Logee’s catalog is known for its vast selection of tropical container plants, dwarf citrus trees, vines and climbing plants, flowering houseplants and other exotic plants. The family-owned company also operates Logee’s Greenhouse in Danielson, Connecticut, a destination greenhouse for thousands of gardeners throughout the Eastern United States.