How to bring tropical flair to a Philadelphia garden

For decades, Eve Thyrum’s expansive garden at Frog Hollow was well-known in her Wilmington community. She often invited fellow gardeners to stroll the 2½ acres, which featured fountains and ponds, a gazebo, and a large pavilion.

After moving to Kennett Square in 2018, Eve began planting again.

In addition to her inground garden beds, she lines her long driveway with huge pots that overflow with stunning tropical foliage each summer.

“I want to focus on color and leaf texture,” said Thyrum, such as the elephant ears’ verdant heart-shapes, the canna’s red and orange glow, and the banana’s sometimes-purple streaks.

Philadelphia-area gardeners like Thyrum are embracing tropical plants as dramatic additions to home gardens. Whether in a container, flower box, or backyard bed, tropical foliage adds height, vibrant color, and texture to replace or enhance a traditional flower garden.

“A lot of those plants were popular during Victorian times,” said Andrew Bunting, vice president of horticulture for the Pennsylvania Horticultural Society (PHS).

But now many more varieties are easy to find. Elephant ears, for example, include varieties that are 14 feet tall and come in many colors including deep purple and chartreuse. Tropicals enjoy the heat and humidity of Philadelphia summers, cover a lot of ground, and require relatively easy care.

“Particularly in the summer months, there’s a desire for more dynamic color and large florals,” said Celeste Starita, director of operations for Urban Jungle Designs in South Philadelphia. “You can use tropicals with other subtler annuals and perennials and have a nice dynamic planting.”

Tropical plants are relatively easy to maintain, Bunting said. Beyond heat, humidity, and regular watering, they benefit from fertilizers high in nitrogen. Like other plants, they require removing the dead leaves and spent flowers to stay healthy.

Whether you are limited to a window box or container garden, or you have a large backyard plot, you’ll want to make the tropical plant a centerpiece and surround it with annuals or perennials.

“You need a thriller, a filler, and a spiller,” said Bunting. “The thriller can be the canna, elephant ear, or banana; the filler can be something more bushy, like a salvia or marigold; and the spiller would be something that cascades, like a petunia or verbena.”

In a garden filled with perennials and shrubs, tropical plants add visual interest and get larger and more robust throughout the summer. Even in window boxes, semidwarf cannas can be the star of the show.

Mandevilla, which come in flowering, climbing, and mounding varieties, work well on a trellis, arbor, or post.

Hibiscus, available in tropical or hardy varieties, have huge, colorful flowers, and birds-of-paradise thrive outdoors in summer but also indoors in colder months.

Lantana, flowering shrubs, are loved by pollinators and resistant to deer.

“There are no rules about how much you can mix together, as long as you consider the amount of water and sunlight they will get,” said Starita.

In arranging a group of tropical plants, you’ll want to make sure each variety requires the same amount of light and water, and consider how quickly each type grows.

“For example, a sweet potato vine takes off immediately, but a begonia is a slow-growing plant,” said Brandon Jackson, lead designer, Potted Perfection in Point Breeze. If they’re planted together “the sweet potato vine can take over.”

Wait until after the last frost to plant them — typically after May 1 in the city and May 15 in the suburbs. There’s no advantage to planting them earlier because they won’t start growing until the soil has warmed.

Tropicals may be a bit more expensive than annuals and other perennials, partly because they are larger when you buy them.

“But you’ll get a bigger bang for the buck,” said Bunting.

Some tropical plants may survive a mild winter, like cannas in the Philadelphia area. But it’s safer to bring them indoors for the winter if you want to replant them the next spring. After the first frost, cut the plant to the ground and dig up the roots beneath the soil.

That may look different depending on the plant. For example, for canna you will dig up the rhizomes, which are the fleshy underground stems, while elephant ears have large, fleshy tubers, and bananas have a trunk. Research the type of plant you want to keep to be sure you are digging up the right part.

Bury those roots in leaf compost or mulch in a nursery pot or other container, and place in a cool, dark basement for the winter.

Many plants kept indoors throughout the colder months thrive outside in warmer months. But allow them to adapt gradually. Wait until after the last frost and be careful of nighttime dipping temperatures.

Don’t automatically repot your plants when taking them outside, Jackson said. A lot of indoor plants like a tight pot and you don’t want to shock them with too many changes at once. If the plant grows quickly and outgrows its pot, give it a few weeks to adapt to its new environment and then replant it in a pot one size (or two inches) bigger in circumference.

He also recommends adding an organic fertilizer filled with micronutrients.

“When reintroducing the plants outside, keep them in a partly shaded environment where they will get indirect sun,” said Jackson.

It’s important to research the specific plant’s needs. For example, putting a shade-loving plant in full sun will burn it. And some plants will dry out quicker outside, so be sure to check daily to see if they need water.

“You don’t want to overwater them,” Jackson said. “Be sure your pots have the proper drainage. Plants can get soggy roots which will detract from the health of the plant.”