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Annual vines provide color in late summer

This time of year, an abundance of annual vines suddenly appears in garden stores. Annual vines are inexpensive to grow and fun to play with, and have the added virtue that they are at their best in August and September, when flower gardens can be in need of a lift. Plant them in the ground or in containers, and try something different every year. Vines are wonderful for softening blank house walls, concealing unsightly fences and adding instant height in young or temporary gardens. You can support them on fences, trellises or pyramids made out of canes, but vines love the company of other plants. My favorite way to grow annual vines is to let them scramble up a shrub or a large perennial.

Garden stores offer many eye-catching trellises and plant towers. They look appealing and make nice gifts, but there’s a catch: Many are far too small and flimsy to support most common perennial vines and climbers. If you’ve ever wondered what to do with that adorable plant tower or mini trellis gathering dust in the shed, an annual vine may be the answer. Especially if you don’t overfeed it. The smallest plant supports probably belong in containers. Small annual vines are great in pots because the confined root space tends to restrict their growth and bring them into bloom sooner. My personal favorites for containers and other confined spaces are Mina lobata, the violet-flowered morning glory (‘Grandpa Ott’), black-eyed Susan vine (Thunbergia alata) and chickabiddy (Asarina scandens).

Mina lobata, a morning glory relative also called Ipomoea lobata, is a twiner with dark stems and shapely leaves, and spikes of long-lasting tubular flowers that open scarlet and fade through yellow to cream. Black-eyed Susan has cute and showy flowers (yes, with black “eyes”) in white, orange and various shades of yellow. The flowers of chickabiddy are tubular (it is sometimes called climbing snapdragon, but the flowers are more like small foxglove flowers) and there are white, pink and blue-purple flowered varieties. Starts of Aserina are sometimes difficult to find, although they seem to come readily from seed. Not as readily as ‘Grandpa Ott,’ though, which is a prolific self-sower in the garden.

Other good candidates for small structures in pots are semi-trailing varieties of fuchsia, flowering maple (abutilon) and Cape fuchsia (phygelius). A sturdy 4-foot tower in a large pot could even support a clump of tall, heavy-headed lilies. Annuals and tender plants grown as annuals, such as verbena and geranium (the geraniums that are really pelargoniums, that is), offer many more possibilities, and any number of exotic foliage plants are fun to train on a small trellis. Tall annuals look great growing through and around a pretty tower in a pot. Try two, or combine one with a twiner. Lime-colored Helichrysum with purple Asarina would be a knockout combination. (When I had a golden arbor vitae, I loved to grow Asarina on it.)

Ivy leafed and scented geraniums — or any upright geranium that’s not too compact in growth — are good plants to train on a wall-hung trellis. Look for old-fashioned varieties such as those with variegated leaves, some of which have not had all their rangy, clambering tendencies bred out of them. My favorite is ‘Frank Headley’ with salmon flowers. I grow it in pots at the foot of an east-facing wall, where it is protected from hot afternoon sun. With a bit of encouragement, the plants grow to three feet or so. Pelargoniums are brittle, so be prepared to shorten or remove branches that grow away from the support, rather than try to redirect them.

Where you have room for something bigger, sky flower (Thunbergia grandiflora) is a gorgeous option with large, clear blue flowers. It can grow to 20 feet and more in a warm place. In Hawaii it climbs trees. Here you might get 10 feet out of it. Another fast vine that should be great for seasonal screening is the hyacinth bean (Dolichos lablab), a stunner with spikes of violet bean-flowers that are followed by purple pods.

Then, of course, there is the ever popular morning glory, Ipomea ‘Heavenly Blue,’ which will romp up a wire fence in no time.

Cardinal climber (cypress vine; Ipomea quamoclit), a morning glory relative with small, palm-like leaves and bright red flowers, performs reasonably well in light shade. Another option for a less than sunny spot is Canary creeper (tropaeolum peregrinum), a climbing nasturtium. This one grows most easily on a shrub. If you have no shrub for it, provide a fine-textured support such as deer or bird netting.