There are surprisingly many tropical plants that demonstrate considerable tolerance and hardiness to cold winters in temperate regions. Although each plant species may require different needs or have varying tolerances to prolonged cold, several plant types can be investigated and grown in the ground or in movable containers where winters are filled with frosts or hard freezes. Contact local botanical gardens or Cooperative Extension offices for lists of hardy plants.
USDA Cold Hardiness Zone
The United States Department of Agriculture publishes a map of North America that classifies regions according to their annual winter minimum temperatures. Not an exclusive tool to determine a plant's ability to survive the winter, or its hardiness, this map and its zone designations are universally accepted as a reference by bother plant nurseries and garden literature resources.
Tropical plants often are regarded as native to or hardy to conditions in Zones 9 or higher. Many plants survive colder winters, including some to Zone 6, 7 and 8.
To determine the USDA Plant Hardiness Zone designation for your home location, have your ZIP code available and visit the National Gardening Association's website.
Palms, whether with feather-like or fan-shaped fronds, can be used in regions with freezing winter temperatures. The tolerance and survivability to winter cold is specific to each plant species as well as the health of the palm at the onset of cold. The world's most cold hardy palm, surviving winter lows to -5 degrees Fahrenheit is the shrub-like needle palm (Rhapidophyllum hystrix). Windmill palms (Trachycarpus) have fan-like fronds and grow on upright trunks, hardy to 0 degrees. In the range of 5 to 10 degrees, the scrub palmettos (Sabal etonia and Sabal minor) survive; saw palmetto (Serenoa repens) to 10 degrees.. A much larger selection of palms with trunks are known to adapt to winter lows from 10 to 15 degrees, including jelly/pindo palms (Butia spp.), European fan palm (Chamaerops humilis), Chilean wine palm (Jubaea chilensis) and two species of parlor palms (Chamaedorea microspadix and Chamaedorea radicalis). With winter temps in the lower 20s Fahrenheit, the choices increase even more, to include Washingtonia spp., Brahea spp., date palms (Phoenix spp.) and fan palms (Livistona spp.).
These ancient plants, that resemble palms, are related to conifers, the cone-producing evergreens. Cycads have a thick stem with waxy fronds, and grow in soils that are well-drained. Plants prosper in full sun exposures to light shade, depending on the heat intensity in your summer climate. King sago (Cycas revoluta) is popular across the American South and in the Southwest, where is tolerates winter lows down to 18 degrees Fahrenheit well. Coontie (Zamia floridana) is a low, clumping cycad nice in woodlands or mixed borders that is hardy down to 10 degrees Fahrenheit. Gum palm (Dioon edule) has a feathery frond that is prickly, also hardy to the same winter low temperature.
Lush foliage plants of the tropics that grow from thick stems and roots are often well-suited to overwinter underground in regions with mild but subfreezing winters. As long as winter soils are not soggy and sometimes if a thick layer of leaf or straw mulch is placed atop the dormant roots, their ability to survive the winter is increased. Often retaining the above-ground frost-killed foliage aids in protecting the underground plant parts from freezing spells across the rest of the winter months. Cut back the dried material in early spring when frosts are fewer and mild.
Gingers (Alpinia spp. and Hedychium spp.) are hardy in regions where the winter lows become no colder than 0 to 5 degrees Fahrenheit. Bananas, in particular the Japanese fiber banana (Musa basjoo) is especially resilient, returning after winters in southernmost Canada. Florist amaryllis (Hippeastrum) and lily-of-the-Nile (Agapanthus) grow from bulbs and may retain their foliage if winters are not too cold, but the underground parts remain alive down to 10 to 18 degrees. Also consider growing certain species of crinum lily (Crinum spp.) or the candy corn plant (Cuphea micropetala) if winters never get colder than 5 degrees Fahrenheit.
Gardeners in the American South can also attest to begonia (Begonia grandis), lantana, elephant ears (Alocasia and Colocasia), voodoo lilies (Amorphophallus) and even dahlias' abilities to go dormant in the ground across a chilly winter and re-sprout in spring to early summer when soil temperatures are optimal. Winter lows should no dip much below 5 to 15 degrees Fahrenheit to ensure these plants' healthy return.
Century plants (Agave spp.) are surprisingly resistant to the cold of winter even though their thick leaves are full of juicy fibers. Naturally, a drier soil that has excellent drainage is required for these succulent plants, but a wide variety of century plants can be enjoyed across regions with winters that have temps as low as -10 degrees Fahrenheit. This resilience to prolonged winter cold varies per species, but among the toughest is Agave lophantha, Agave parryi and Agave gentryi.
Yucca is another staple of arid regions that demonstrate excellent winter hardiness. Yucca linearifolia and Yucca rostrata are two species with attractive powdery blue-green foliage.