All About Gardening and Gardening Q & A
by Pernell Gerver

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"Exotic Tropicals For Beds and Borders"

In recent years there has been a lot of interest in growing tropical plants in beds and borders. Tropicals are also used effectively as focal points and accent plants in containers, around patios, and near ponds and swimming pools where they fit right in. Tropical plants add an exotic look unmatched by other plants.

Tropical plants have their own unique look. Usually flowers are bright and bold. Foliage on tropicals is often flashy, dramatic, and big. In short, tropicals put on a show on a grand scale.

Now that the weather has warmed sufficiently it's time to plant tropicals outdoors. They love the warm and humid weather of summer and really thrive in it.

I enjoy growing tropicals in the garden wherever I need a big splash of color or want to make a statement. I've seen gardens here in New England planted entirely of tropicals and it seemed as if I was walking through a jungle in the tropics.

There are many tropical plants and plants that have a tropical look that you can plant to enjoy their tropical flair all summer long.

Persian ShieldPersian shield is an exotic tropical with striking, iridescent foliage. It has long, lance-shaped leaves that are silvery purple on top and deep maroon underneath. When the sun hits the leaves, they shimmer. The leaves have prominent, dark-green veins that give them a striped look. The colors on this plant are unlike any other. It's a shrubby plant, growing about a foot and a half tall with woody stems. Pinch it occasionally to increase its bushiness. Its leaves are the most colorful in partial shade. Combined with gray-leaved plants, the effect is striking.

Zebra-leaf bananaZebra-leaf banana is a large plant that offers a very tropical look to the garden. It's a fast-growing plant that can reach 10 feet tall by the end of the summer. It has enormous leaves that unfurl from a thick, central trunk. The large, lance-shaped leaves are green striped with red. It makes a bold statement in the garden and looks right at home beside a water garden or pool. Plant it in full sun and stand back because it will really take off, especially when the heat of summer sets in.

Canna 'Tropicanna'Cannas are tropical rhizomes that offer big, bold leaves and flowers. One of the showiest cannas is a variety named "Tropicana." The foliage of this canna is not the ordinary green of most cannas. The large leaves emerge deep purple as the rhizomes begin to grow. As the leaves mature, they become deep maroon-green. Each leaf is striped with bright green, yellow, pink, and red with a bright-orange stripe running the length of the leaf in the center. The colorful foliage is reason enough to grow this canna, but it also bears tall spikes of bright-orange flowers. Canna "Tropicana" grows five to six feet tall.

Purple Fountain GrassPurple fountain grass is a tropical grass that forms a handsome clump of dramatic maroon-purple slender foliage. It bears slender, dark red flower plumes from June to frost. It's a beautiful plant for containers or flower beds and I use it both ways. It grows to three feet high and half as wide.

Pernell Gerver's Gardening Q & Aby Pernell Gerver

Wisteria Notorious for Not Blooming"

Q. My wife and I have a wisteria vine and we have tried everything for the last four years to make it flower, but there have been no flowers yet. May I please have some advice on how to make it bloom? Thanks.

A. A wisteria vine in full bloom is a sight to see in late spring. Long blue or white fragrant flower trusses cascade as if dripping off the substantial vines. Wisterias are beautiful in bloom, but they are wisterianotorious for not blooming. Sometimes wisteria vines are stubborn and refuse to bloom. This is especially true of young wisterias. It's not that the vines are weak, to the contrary, older wisterias have thick, trunk-like stems and are many times holding up rotted porches and railings on very old homes. The strong vining stems grow rapidly and wrap around anything they can grab onto. It's mind boggling that such a vigorous plant is so difficult to bloom. With non-blooming wisterias, the key is being persistent and patient.

Wisterias grow best in full sun and moist soil. A young plant needs at least 10 years to get established. If the plant was raised from seed, then it could take even longer. For a blooming vine, a late cold snap might kill flower buds.

If after 10 years, and the cultural conditions are right, and the wisteria still refuses to bloom, then action should be taken to coerce the stubborn vine into bloom.

The following flower-inducing methods may appear drastic, but consider it "tough-love" - the reward might just be a beautiful, blooming plant.

Wisteria vines put on much vegetative growth during the summer. Make sure to keep these long whip-like growths trimmed back constantly.

Flower trusses appear on next year's new growth, so at each pruning, trim back the vines to two nodes (where the leaves join the stems). Because the vines are so vigorous, pruning it several times during the season is not out of the question.

Thin extra vines so there is room for sun and air to get through. Don't be afraid to prune wisteria hard.

Wisterias reluctant to blossom sometimes respond to root pruning. Use a good sharp spade and slice a few feet out from the stems, all around the vine. Push the spade back and forth in the ground, making a trench, and add superphosphate. Use a few pounds for each inch of trunk diameter. Mix it into the soil in the trench and then close up the crevice. The superphosphate will encourage blooming. Do not use fertil