Flowering vines add color, dimension

This spring I am indulging an interest in annual flowering vines that grow rapidly from seed or from nursery-grown transplants. In the ground or in pots, they bring both color and added dimension to the summer garden.

Black-eyed Susan vine (Thunbergia alata) I know well, first growing it many years ago in South Carolina where the long, hot summers allowed it to reach its full tropical potential. Planted in hanging baskets, its slender stems, 6 feet in length, twined up strings nailed to the porch posts. It bloomed all summer, long-stalked, tubular flowers of orange-yellow petals and purple-black throats. Perhaps less exuberant in Maine’s cooler and shorter summers, it is still worthy of a sunny space in our gardens.

What is new for me is the range of flower colors now available in this vine. Marjorie is indulging my desire to grow them all, lining them up in pots on the porch railing where they can twine upward or trail down. I have planted ‘Lemon Star’ with clear, bright, lemon-yellow petals and a throat the color of red wine; ‘Raspberry’ with light pink petals and a deep raspberry-red throat; and ‘African Sunset’ with its apricot-orange petals and purple-black throat. I am still looking for someone selling the old original.

Last summer I used another exuberant annual vine, hyacinth bean (Lablab purpureus, previously Dolichos lablab), to disguise the city’s “No Parking” sign on the street-side edge of my Orono garden. I planted several seeds at the base of the signpost in early June, and by mid-July the sign’s post was wrapped in dark green, purple-veined leaves and large clusters of deep violet and white pealike flowers. The blossoms soon were followed by ruby-purple seedpods. Neighbors out for a summer evening stroll would stop to admire this vine and, finding me working in the garden, ask about it. People driving by would park on the street in front of the vine to admire it.

I grow annual vines into the canopy of small trees and shrubs to add a little color to the summer garden. I learned this trick from a transplanted English gardener who planted a purple-flowering clematis vine at the base of a Japanese maple, using the tree’s branches as a scaffold for the vine’s summer blooms. I have used Cypress vine (Ipomoea quamoclit) in a similar manner in my Orono garden, planting seeds at the base of my fringe tree (Chionanthus virginicus) and allowing its slender, fragile stems to twine into the tree’s canopy. The dark green leaves of the small tree serve as the perfect summer foil for this dainty vine’s lacy foliage and small, tubular, scarlet flowers. I want to do this for Marjorie this summer, in her garden where the same fringe tree now grows.

A selection of annual vines

A stroll through the greenhouses at Everlasting Farm on Essex Street in Bangor is an eye-opener for any serious gardener. Here are some of the annual vines I spotted on a recent visit:

. Several forms of Thunbergia, including those mentioned above as well as ‘Blushing Suzie,’ its petals blushing red-salmon with a dark red throat. Also Thunbergia battiscombei (bush thunbergia), a species new to me. Since there were no open flowers, I asked plantsman Michael Zuk, owner of Everlasting Farm, to describe the blooms. “Royal purple saxophones,” he replied with a broad smile.

. Two cultivars of sweet potato vine (Ipomoea batatas), ‘Blackie’ with dark purple-black, deeply divided leaves and ‘Margarita’ with yellow leaves. Both are trailing vines, excellent for containers, growing only 6 inches high but spreading up to 5 feet in a season.

. Lophospermum ‘Wine Red,’ a vine with a cascading, semiclimbing habit and rich burgundy-wine tubular flowers.

. Brazilian firecracker vine (Manettia luteorubra) with vibrant orange and yellow tubular flowers that look explosive.

. Orangeglow vine (Senecio confusus ‘Sao Paolo’) from Mexico, with glowing orange daisylike flowers.

Send queries to Gardening Questions, 116 N. Main St., Orono 04473, or e-mail rmanley@adelphia.net. Include name, address and telephone number