Faking the tropical look — The Wandering Weasel

Gardeners around the world are envious of those fortunate enough to live in climates where tropical flora can be enjoyed in the garden year-round. If you are one of those who would like to add a touch of the tropics to your yard, here are some helpful tips (and tricks) to replicate a tropical paradise in your own back garden.

Big is beautiful. Generally, the bigger the leaf, the more ‘tropical’ the plant appears. The tropical zone does not have a monopoly on large-leaved plants, of course; they can be found in colder regions, just not in the same quantities. Catalpa bignonioides and Catalpa speciosa trees are native to North America and grow large, heart-shaped leaves up to 30cm (one foot) in length. Paulownia tomentosa, also called the princess tree or foxglove tree is native to China and is hardy to zone 5. This tree gives gardeners two options – if pollarded or coppiced annually, the tree will not flower, but will grow immense leaves two feet across or more. If left to grow, the leaves will be smaller but the tree will be covered in beautiful pink to lilac flowers in spring. Another cold-hardy tree with unusually-large leaves is Magnolia macrophylla, the bigleaf magnolia. This deciduous tree is native to the eastern US and is hardy to zone five. It’s flowers are large and white and have the typical magnolia appearance and are very pretty, but the tree’s leaves are what really catch the eye. As the common and scientific names state, the leaves are big – they can grow almost three feet in length and a foot wide.

Gigantic leaves are not the demesne of trees alone. One of the first plants to emerge from the cold winters of North America is Symplocarpus foetidus, the eastern skunk cabbage. Named after the odor of the leaves when damaged, this plant first grows pretty yellow flowers that are followed by leaves that can be up to half a meter (1.5 feet) long and nearly as wide. This is a good plant for those eager for winter to end, as the plant is thermogenic, meaning it generates heat to melt the snow around it as it emerges in spring. It’s not just gardeners that are impatient for spring! The leaves die back in late summer, but there are other large-leaved, herbaceous plants that have large leaf sizes that peak at that time of year including the common garden plants rhubarb and burdock. In particular, Chinese rhubarb, Rheum palmatum, is more often grown for its impressive foliage than for its leaf stalks. Chinese rhubarb can grow leaves up to three feet (one meter) wide and grow to ten feet (three meters) in height. There are green and purple forms of this dramatic plant.

If your garden is situated in a place with winters that are cold but aren’t terribly severe, you have more options available to you. Gunnera is a genus of plants mostly from the southern hemisphere that grow enormous leaves – the leaves of Gunnera tinctora, which is hardy to zone seven can be six feet wide! Another plant suitable for colder areas with giant leaves is Tetrapanax papyriferum, the rice paper plant. This is a shrub that grows to about twelve feet in height with palmately-lobed leaves that can be two feet across or more. This plant is hardy to zone 8. The genus Amorphophallus has multiple species that can survive cold winters, A. konjac being able to overwinter successfully in zone five. These plants die back each autumn, then send up very unique-looking flowers followed by equally-unique looking foliage. The cold-hardy varieties tend to stay smaller, usually under six feet (two meters) in height, but the tropical ones can be truly huge- A. titanium has the largest unbranched inflorescence (flower spike) of all plants which can grow several meters (several yards) tall. The distantly-related genera of Arisema and Typhonium have similar growth habits and also add a touch of the exotic to your garden and most species are even hardier. In these places without too-severe winters (zone 8, possibly zone seven with protection), other tropical-looking plants such as Tasmanian tree ferns (Dicksonia antarctica), New Zealand flax (Phormium tenax), Yucca rostrata, angel’s trumpet (Brugsmania), and a few different large, clumping bamboo species can be planted outdoors without much concern.

Podophyllum plants have a delightfully unique, exotic look.

A young Rheum palmatum, foreground. A young Musa basjoo, left. The plant with the purple, palmate leaves in the centre is Ricinus communis, the castor bean. This small, tropical tree is often grown as an annual in cold climates and adds a nice touch…

A young Gunnera tinctora growing in Littlebury, Essex, UK.

Arisema are delightfully-exotic looking plants that die back to corms each year. This genus includes the Jack-in-the-pulpit (A. triphyllum), and most species have flowers that look similar.

Tropical gardens tend to have a bit of an ‘overgrown’ look, so those familiar with similar garden styles such as English cottage gardens should find this comfortably familiar. Bright patches of colour interspersed with lush ferns and large-leaved plants growing together in carefully-managed chaos can impart a tropical look with many cold-hardy plants. Textural contrasts help with the balmy illusion. The paperbark maple (Acer griseum) is hardy to zone four and has eye-catching, orange, peeling bark that looks more appropriate for a tropical tree.

Capsicum annuum ‘Black Pearl’ has intense, dark foliage and tasty and hot fruit, and provides wonderful visual and textural contrast in the garden.

You can also turn the familiar into the exotic by displaying certain plants in creative ways. For example, ferns and hostas are commonly grown in gardens in cold climates. If instead of planting them in the ground you plant them at the top of a column made to look like the trunk of a palm or tree fern, suddenly they take on a dramatic, exotic look. Temporarily removing bromeliads and birds nest ferns from their pots and nestling them into the forks of tree branches also adds a tropical flair to your garden. You can even permanently attach pots to trees and disguise them with moss to grow cold-hardy ferns or hanging vines in the trees in your yard. This also works well with boulders.

The author’s ‘tropical’ garden in England, showing cold-hardy begonias, a young tree fern, a young Mexican fan palm, and a Podophyllum hybrid.

Many plants sold for flower beds in temperate gardens are actually tropical perennials. Plants such as impatiens, coleus, begonias, sweet potatoes, and others that are commonly sold as annuals in garden centres are actually frost-tender perennials. With this in mind, if you have the budget and desire, this can be extended to other tropicals. With the explosion in mass-produced, micropropagated orchids, it is extremely common to find orchids in garden centres marked down to a few dollars. These can be removed from their pots and attached to tree trunks or branches in shady parts of your garden for an extremely tropical look.

Platycerium superbum, a tropical fern from Australia makes a striking summertime addition.

One way to heighten the tropical look of your garden is to include actual tropical plants. In this case, selecting plants that are well-known works best, as familiar foliage draws the eye when spotted in an unexpected (temperate) area. Selectively placing tropical containerised plants in strategic places in your landscape makes it look like these delicate beauties from low latitudes look like they’ve been there all along. Pots can be hidden by other plants, stones and decorative objects. Prominently positioning a brightly-coloured croton or another houseplant where it will naturally attract the eye can make your garden appear like it contains more tropical plants than it actually does. Additionally, tropical bulbs and corms are commonly available for sale in many garden centres and online. Caladiums, elephant ears, ismene, cannas and other tropical plants can be purchased and planted in the ground once the weather is warm enough. These bulbs can be dug and stored in a frost-free location during the winter.

Birds nest ferns and hybrid Phalaenopsis orchids temporarily attached to a Ceanothus (California lilac) tree for the English summer.

Another option is to plant tropical plants right in the ground with the intention of digging them up again in autumn. This is a popular choice for plants like the Abyssinian banana (Ensete ventricosum), a banana relative with enormous, upright, maroon-tinged leaves with red midribs. This plant tolerates being dug up and stored in a cool place quite well, like a giant canna. The cold-sensitive Amorphophallus species are often grown like this as well, but not all plants are suited to this treatment. It is primarily plants with corms or that have a dormancy period in their native homelands that can be dug up each autumn and stored in a garage, unheated basement, or other freeze-free, cool location.

If having to dig and replant your tropicals annually seems like too much hassle, fret not, as there are alternatives. Depending on how cold it gets and how long the winter weather lasts where you live, you might be surprised by the plants you can coax to grow in your garden against conventional wisdom.

If the winters are just a bit too severe for the plants you’d like to grow where you live, you can try planting them in sheltered areas – against a heated building works best, but often just getting them out of the wind and nestled somewhere can sometimes be enough to get a plant to survive a USDA zone or two colder than they normally would. You can also build shelters to shield your plants from the worst of the winter. These do not typically need to allow light to reach the plants, as they’ll be in a dormant state anyway. Lean-to shelters will further increase the warmth provided to plants from buildings, and some eager gardeners even build mini-greenhouses with heating each autumn over their treasured tropicals. One exceptionally-industrious individual in the St. Louis, MO region would build 40 foot (12 meter) high greenhouses with construction scaffolding and plastic sheets over his Washingtonia robusta (Mexican fan) palms each autumn.

Amorphophallus, centre, are commonly grown outdoors in summer and dug up and stored inside when they go dormant.

Potted plants can be used to add a tropical feel when placed in the garden.

The large leaves of Musa basjoo, a cold-hardy banana growing in Littlebury, England, starting to arch over the neighbour’s conservatory. This particular banana grew twelve feet tall in one English growing season

Some plants that would commonly be considered ‘tropical’ such as palms and bananas have some surprisingly cold-tolerant members. The Japanese fibre banana (Musa basjoo) has become easy to find online and in specialist nurseries. This beautiful plant is strikingly-tropical in appearance; its long, wide, arching leaves stretching two yards (two meters) or more and can reach up to fourteen feet in height. This banana is even root-hardy even as far north as zone 5 with heavy mulching! The leaves and stems will die back with freezing weather, but the stems can be saved if your temperatures don’t get too low by building wire enclosures around them and stuffing them with leaves for the winter. The leaves grow so rapidly that it’s not worth the effort to protect them; as as soon as spring returns they’ll be unfurling like banners heralding the arrival of the next growing season.

Palms are perhaps the most iconic image of the tropics, and there are palms that will survive colder weather than you might expect. The windmill palm (Trachycarpus fortunei) is a palm from the Himalayas that not only endures, but prefers cool, mild climates. This palm thrives in the not-at-all balmy climates of the British Isles and Vancouver, Canada, and rare specimens can even be spotted in Scandinavia. There are palms that can take even colder temperatures – The needle palm (Rhapidophyllum hystrix) is native to the southeast United States and can be found planted in gardens as far north as Cape Cod. The mazari palm (Nannorrhops ritchiana), found in southwest Asia, is another that can withstand a lot of cold. Both of these palms can endure temperatures sometimes as low as -4f (-20c), but neither grow as trees (they are shrubs), and both require hot summer temperatures and will struggle in places with cool summers like the UK and Pacific Northwest. The mazari palm is also only suited to dry climates. These are the two champions of palm cold-endurance, but there are others that handle cold temperatures well, such as Sabal minor (dwarf palmetto) and Chamaerops humilis, the European fan palm.

If tropical fruits are what you fancy, there is a tree native to eastern North America that is in the custard apple family, a large family of tropical fruits which also includes the soursop/guanábana, cherimoya, and others. This tree, Asimina triloba, or pawpaw, is almost impossible to find in stores despite growing wild in a large part of the continent. The reason is that the fruit, despite being delicious, does not store or transport well. This gives horticulturalists even more reason to grow them at home! Figs are another mainly-tropical taxon, but the common edible fig, Ficus carica, can grow in sheltered locations in places as cold as zone six.

Figs (cold hardy) and papyrus (not cold hardy) growing together in England.

There are a fair few tropical plants that have cold-hardy relatives. The hibiscus is known by practically everyone and is nearly an emblem of Hawai’i. There is a hardy hibiscus, Hibiscus syriacus (rose of Sharon), which can survive zone five winters and has instantly-recognisable hibiscus flowers. Passiflora incarnata is a passionfruit (passionflower) that survives zone six winters and also produces edible fruit. There are several cold-tolerant eucalyptus trees – Eucalyptus pauciflora, for example, is an evergreen tree and can survive in snow, taking zone seven winters without trouble. The common houseplants Schefflera arboricola and Schefflera actinophylla have cold-hardy relatives that look similar but can take zone seven winters, such as S. delavayi and S. brevipedunculata. There are also tropical look-alike plants; for instance, the golden shower tree, Cassia fistula, looks very similar to the quite cold-hardy (to zone 5) Laburnum anagyroides, the golden chain tree.

Aristolochia fimbriata, the white-veined Dutchman’s pipe has bizarre flowers and is a cold-tolerant (to zone 7) species in a mostly tropical genus.

Armed with this information, you can now add touches of the tropics to your own garden. With careful consideration, you can even turn your garden ‘tropical’ without adding extra work, leaving you with more time to enjoy your personal paradise.

A view of the author’s garden in spring.

A dead tree decorated with hardy and tropical epiphytes (air plants)

Another view of the author’s tropical garden.