Mandevilla, Dipladenia, Allamanda

I received a Mandevilla vine as a Mother’s Day gift this year. A wooden trellis was included. It dwarfed the plant. Fast forward two months, and this woody vine is a knockout! Healthy, dark green leaves set off the blood-red, tubular flowers to perfection. The vine has grown enough to cover the trellis without becoming aggressive.

Mandevilla (pronounced man-de-VILL-uh) has large, tubular blooms that attract hummingbirds. Mine is red but I have also seen pink, rose, yellow, and white in nurseries. The vine does not have suckers, but will twine gently around a supporting trellis. They make an ideal mailbox-post accent or hanging basket. Dipladenia (rhymes with Gardenia) is an upright, bushier form of Mandevilla that is now included into the Mandevilla genus. To confuse matters further, some were formerly labeled as Allamanda. The upright forms have smaller, more pointed leaves than the original, viney Mandevillas. All types enjoy rich, moist soil that drains rapidly. A mixture of potting soil, sand, and ground bark works well. Spent blooms fall off without any help from the gardener. Pinch the tips of vines to make plants fuller. In the southeast, Mandevillas will appreciate afternoon shade and frequent irrigation.

Mandevillas are warm weather plants, winter-hardy only in zones 10 and 11. This is why many of them are grown in containers, to facilitate bringing them indoors for winter. Container culture also restricts the mature size. Grown directly in the ground, a vine may reach 15-20 feet. In a container, it will rarely exceed 6 feet. When night temperatures drop to 50 degrees, Mandevilla can be brought indoors to a bright location (no direct sun) and enjoyed as a houseplant, although flowers are fewer than in summer. Water indoor plants sparingly, allowing soil to dry out while giving them a winter rest. Keep an eye out for aphids, whiteflies, mealy-bugs, and scale. Remove any dead or damaged leaves. Prune hard and apply liquid fertilizer when they return to an outdoor location in spring.

Mandevilla ‘Red Riding Hood’

Trumpet Vine or Crossvine?

“What is that gorgeous orange-red vine blooming right now?” I receive this inquiry every year. I only need to look at the calendar to answer. If the question comes in spring, I know the vine is Crossvine (Bignonia). If it is summer, the answer is Trumpet Vine (Campsis), also known as Trumpet Vine or Trumpet Creeper.

A Trumpet Vine bloom. This flower is several days old, so it is a pinkish red. Newly opened flowers are a bright orange-red.

Bloom time notwithstanding, there are distinguishable differences between the two. The tubular blooms appear the same, but a closer look will reveal that Crossvine is a reddish orange with a yellow throat, while Trumpet Vine is a solid red, orange, or (rarely) yellow. Crossvine leaves have smooth edges and are evergreen, taking on red or purple tints in cold weather. The vines have tiny little tendrils that they use to climb trees or trellises. Trumpet Vine leaves are attractive, toothed and compound, with 7 to 11 leaflets. The leaves shed in cold weather. Trumpet Vines have little sucker feet that stick like glue to whatever it are climbing. The vines become thick and woody with age, like wisteria.

Both these plants are lovely when in bloom, but Crossvine is much better behaved. Trumpet Vine is aggressive and considered invasive throughout much of the southeast. Crossvine will sucker, but Trumpet Vine throws out long underground runners that surface in the form of new plants. The weight of a mature Trumpet Vine can damage trees. Above soil level, it is a Medusa-like thug that throws waving stems in all directions.

Crossvine will grow in sun or shade, in zones 6 to 9. It blooms most heavily in sun and prefers a neutral soil. It will tolerate drought or short periods of standing water. It will reach heights of up to 50 feet, but accepts pruning to keep it shorter.

Trumpet Vine produces plentiful nectar, beloved by hummingbirds and ignored by deer. If your garden has space for a large, privacy-making evergreen vine, give native Crossvine a try. Other polite, evergreen alternatives include Confederate Jasmine and Clematis Armandii.

The exuberant foliage of Campsis

Well-behaved crossvine atop a pergola