Many modern semi-tropical cultivars have been bred to withstand colder temperatures, more extreme site conditions and carry resistances to disease and even pests. The options are impressive when you do a little research.
Tropical plants in the landscape invoke the scent of the islands, the sultry brush of warm breezes and the kiss of sun on winter starved skin. Most tropical plants are suited for USDA zones 9 to 11 and have no freeze tolerance. This means the northern and even temperate gardener will not be able to add the majority of these tender specimens to their garden design. Demand for the exotic look in landscaping has encouraged the development and breeding of hardier varieties of plants that were once too tender for most areas of North America. It has become a huge business and plant breeders are working round the clock to bring us those exotic and coveted plants. You can now have a banana tree in your garden in Seattle or a brilliantly hued passionflower outdoors in Nebraska.
Investigation and research are important parts of introducing tropical to the home landscape. The last thing you want to do is spend money on a yearned for specimen only to have it succumb the first winter. Know your United States Department of Agriculture plant hardiness zone. You can visit the website and locate the average lowest minimum temperature for your region.
Palms (mostly members of the Arecaceae family) simply scream tropical paradise and they are some of the hardiest trees available for the cool climate landscape. Windmill palms, Chamaerops, and Phoenix canariensis may be hardy to zone 6 and 7. Some species of Eucalyptus, including E. niphophila, E. coccifera and E. perriniana will thrive in zones 7 to 8. Other ways to bring in tropical dimension to the garden are with crepe myrtles, Bamboo (Fargesia and other cold-hardy types) and dwarf palmetto. Tree ferns are mainstays of the tropical rainforest and provide attractive foliage and height in temperate gardens.
Cactus and succulents have to survive desert temperatures, which include nighttime winter averages below freezing. They are ideal in the landscape. Ferocactus and some Mammallaria can survive temperatures below 0 degrees Fahrenheit. Try a prickly pear, lace cactus or Escobaria for zones with light snow and cold winter temperatures. Some varieties of Stonecrop can thrive below freezing and Agave, Spanish dagger (Yucca) suffer no ill effects from chilly winters. They do not tolerate wet feet, so plan for plenty of drainage. Soggy soil will kill the succulents long before the cold will.
Fruiting exotics supply tempting edibles and provide lush foliage and brilliant blooms. The hardy banana species, Musa basjoo and Musa sikkimensis are suitable for USDA zone 8 and sometimes 7 with protection from extreme wind and snow. The 'Brown Turkey' fig is a large tree appropriate for even zone 5 and will provide sweet succulent fruits for the home gardener. 'Arbequina' is an early bearing olive and will withstand temperatures of 10 degrees Fahrenheit. Several cultivars of fuzzy kiwis (Actinidia arguta) bloom and fruit in zones 5 and above. the most hardy of the kiwis, 'Arctic Beauty' has a light pink and white leaf and will live in zone 3 happily. Some vigorous pomegranates varieties are not bothered by light freezes and modest snow. Loquat, Asian pear, Chinese quince, and hardy passionfruit vines grow in zones 7 and above. Do your research before handing over hard-earned money for a tender plant. Chances are, there is a hardier version that will be much happier in your garden,
Tropical flowers like hibiscus don't have to be a pipe dream to the northern gardener. Rose mallow is a cousin of Hibiscus with similar bright flowers and a hardiness into USDA zone 6. Cannas, calla lilies and toad lilies enliven the tropical landscape. Their tubers will survive light freezes but can also be dug up in fall and stored for replanting in spring.
If you are in doubt as to the survival abilities of your favorite plant, try growing it in a container. Foliage plants such as Alocasia, Colocasia and Caladium work well in mixed pots or alone and will overwinter if brought indoors. Bird of paradise, Bougainvillea and Bromeliads are bright additions to the patio garden and will bloom anew the next warm season if brought indoors to a warm dry location. Other protection strategies for tender exotics include heavy mulching on the crown or root zone, tuber and bulb removal, and frost barriers. Remember you can't ask for miracles in the coldest gardening zones, but there are cultivars and species for most regions that will survive cold winter temperatures and arise anew to astound and delight in warmer weather. It is all a matter of preparing yourself to take a bit of extra care, but it can pay off handsomly each summer.