Do you ever feel like you live in the wrong gardening zone? Do you live in a cold zone but crave the dramatic and lush look of tropical garden?
The tropical look is sure to stand out and goes perfectly with hot summers, especially if your backyard has a lounge area or pool. There are lists of so-called cold hardy tropical plants online, but many of them can only survive up to zones 7 or 8, which is considered warm by northern gardeners! This article will describe tropical-looking plants that can survive down to at least Zone 5.
What to Look for When Creating a “Tropical” Garden
Most of us already have a mental image in mind when thinking of tropical places. Tropical climates are sunny, warm, and wet, allowing plants to grow big and close together. You don’t need to rely on tropical plants to get that look if you imitate some key characteristics: large, often shiny leaves, unusually shaped foliage, big and full plants, bold colors, and big or exotic flowers. This is no place for delicate, fine textured plants – especially evergreens. In short, if you want a garden that evokes the tropics you need to go big or stay home.
Grasses look perfect in tropical themed gardens. Aim for broad, flat leaves rather than thin ones and avoid plants that are grown for their fluffy seed heads.
Miscanthus (Zebra grasses) are hardy down to Zone 5. They’re fun, extremely easy to grow, and come in various colors and forms. One of the giant varieties (usually 4 feet wide and 6-8 feet tall) would be a great backdrop for other plants.
Imperata cylindrica (Japanese blood grass) is great choice if you want a smaller and more colorful grass. It is hardy to Zone 5 and grows to about 1 foot wide and 2 feet tall. Japanese blood grass is arguably better for northern climates because it can grow too aggressively in warmer zones.
Bamboo is a type of grass beloved by gardeners for its ability to add an exotic touch to any planting design. There are two types of cold hardy [http://bamboogarden.com/cold%20hardy%20bamboo.html] bamboo: Phyllostachys and Fargesia. Both types can survive and stay evergreen in Zone 5 winters.
Phyllostachys is commonly called “running bamboo”. It grows very fast and tall (up to 20 feet) and spreads indefinitely wide via runners. People typically use running bamboo for privacy screens over large areas, but they can be invasive if they’re grown without pots or barriers [http://bamboogarden.com/barrier.htm]. Don’t plant this type unless you are sure you can contain it.
Fargesia (clumping bamboo) is slower growing, shorter (6 to 10 feet tall and wide) and more delicate. It’s main selling feature is that it spreads very slowly and is easy to contain in a garden.
Hibiscus that grow in temperate climates aren’t the same as the iconic tropical hibiscus, but their massive, beautiful flowers look positively tropical. The perennial Hibiscus moscheutos (rose mallow) is hardy to Zone 4 and grows to an astounding 7 feet tall with a 4-foot spread. Various cultivars have been developed with plate-sized flowers in shades of white, pink and red.
As far as tropical-looking shrubs in cold climates go, you can’t beat Hibiscus syriacus (rose of Sharon). The shrub grows to between 8 and 12 feet tall, is hardy to Zone 5 and tolerates poor soil, heat, and drought. The shrub features an abundance of showy flowers which bloom later than most other garden plants. Some people find the common varieties to be very weedy, producing a lot of seedlings. To overcome this, try one of the newer sterile cultivars, like Lucy and Orchid Satin.
A backyard tropical garden wouldn’t be complete without flowering vines. Vines add color and lush foliage to fences or structures, and hide unwanted views. Flowering vines can also be used as groundcovers.
Some tropical vines are not cold hardy, but they can be overwintered inside, including bougainvillea and mandevilla. There are also some fast growing vines that will flower the first year from seed and can be grown as annuals. These include Cobaea scandens (cup and saucer vine), Tropaeolum majus (nasturtium) and Ipomoea lobata (Spanish flag or exotic love vine).
For less maintenance, opt for cold-hardy vines that have big, bold-colored flowers and generous leaves. Many clematis are hardy to zone 3 and produce lush flowers. Rather than the traditional large flowered forms, try a more exotic form like ‘Princess Diana’.
The five leaf akebia (Akebia quinata) produces a lot of growth, has exotic looking leaves and unusual flowers that smell like chocolate. It is hardy to zone 5.
One easy way to add bold color to your garden is adding some Asiatic lilies which grow 1 – 6 feet tall with long, glossy leaves and large, long-lasting flowers. They can survive really challenging conditions – some cultivars even grow in Zone 2!
Day lilies are technically not lilies at all – they’re from the genus Hemerocallis. Hardy to Zone 3, daylilies are an excellent addition to a tropical-inspired garden. They are considered the “perfect perennial” – they’re attractive, low-maintenance, salt-tolerant, and newer cultivars are non-spreading, and remain a manageable size year after year.
Kniphofia, the Red Hot Poker
Kniphofia (red hot poker or torch lily) is native to South Africa and hardly looks like a plant that would grow in Zone 5. They are famous for their sizzling orange flowers, but they are also available in yellow, lime green and magenta. Shop carefully since not all kniphofia are hardy in zone 5.
A Tropical Touch for Shady Areas
Some areas of your garden might be too shady for the plants recommended above, but you can still obtain the lush, tropical look in the shade.
You can’t really go wrong with Hostas for shade. They’re exotic-looking, tough as nails, low-maintenance and produce long-lasting blooms that attract hummingbirds. Very large Hosta are sure to look great in a tropical garden. Variegated cultivars provide additional tropical interest.
Another large, dramatic plant is Petasites japonicus (Japanese butterbur). Its unique, fan-shaped leaves can grow up to three feet wide. Japanese butterbur can handle any type of soil and even thrives in full shade and loves moisture. It’s an incredibly aggressive plant, however, so it should be grown in an area where it’s rhizomes can’t escape or do what we do at Aspen Grove Gardens. Take a large tree pot, cut the bottom off and sink it in the ground making sure that about 1″ of the lip remains above the ground. Then plant inside that. The runners are quite shallow and won’t escape the pot. Every 7 years we did most of it out, and start new growth. These plants do not seem to set seed – all the plants in cultivation might be male plants.
Many of the above plants provide summer interest. For some spring interest in shady areas, try hellebores and bergenia. Hellebores bloom in early spring but their leathery palmate leaves add an exotic touch all spring and summer long. Hellebores can grow in the shade and require little care. For something really special try the stinking hellebore, (Helleborus foetidus).
Bergenia (pigsqueak) blooms in mid to late spring, slightly later than Helleborus. This plant has tiny pink, white or purple flowers but is mostly loved for its foliage. The leaves are incredibly shiny and thick, making them stand out among cold-climate plants. This plant also prefers shady spots and would contrast nicely when planted next to hostas and hellebores.
Written by: Marika Li