By Norman Winter
Horticulturist
Central Mississippi Research & Extension Center

Sweet potato vines are becoming all the rage as landscape plants. It is not too hard to believe when you realize that many of us grow their close relatives, the morning glories or moon flowers.

These gorgeous plants are not being grown for their tubers, but for outstanding foliage. This vigorous group has outstanding ornamental features. Though they are from the sweet potato family (Ipomea batatas), they are being recognized as a terrific choice for trellises, hanging baskets and planters. They also excel in the landscape as an annual groundcover.

Even though they are new, they are not hard to find. There are three varieties readily available in Mississippi. The most popular right now is Blackie, which is a fast grower with green foliage that darkens to a rich dark purple color as it matures.

Blackie grows well in containers and as a groundcover. I have combined them in containers with trellised Bougainvilleas, pink verbenas and the old ham and eggs lantana. They were super in all instances.

Marguerite is a fairly new cultivar and produces lime-green foliage. You may also find what looks to be the same lime green sweet potato vine being sold under the name Sulfurea and Goldie.

I have seen Marguerite attractively draping a bridge in Bellingrath Gardens near Mobile.

Tri-color is my favorite sweet potato vine. It displays white, green and pink variegated leaves and is as vigorous as Blackie. You would think that the prettiest of all sweet potato vines would have a better name than Tri-color.

All of these sweet potato vines are great in mixed planter boxes where you can combine with complementary blooming plants for an entire summer of beauty. When planted in the landscape, you can plant Blackie and Tri-Color four to six feet apart and let them grow together or plant closer, but they will crowd quickly. Marguerite can be planted on three-foot centers.

The key to having a green thumb with sweet potato vines and most of the other spring plants, may be how brown your thumb gets first.

If you ever wondered why you are such a good container gardener but fizzle after you get off the porch or patio, it is probably soil preparation. Container provide the very best in soil climates. That container with gorgeous flowers has a rich organic potting mix that allows for good drainage and maximum oxygen for roots.

We can achieve the same thing in a landscape bed with proper soil preparation. Work 2 to 3 inches of organic material into the bed and rototill to a depth of 10 to 12 inches. A spade for turning the soil also could be used.

Start getting your soil prepared as soon as it is dry enough. If you work the soil when it is wet, you will pay a heavy price by having large clods resembling bricks when drying does occur.

The organic matter helps loosen heavy clay soils for better water penetration and aeration leading to good root development. In sandier soils the organic matter helps hold water and nutrients.

There is still time for you to get a soil test to determine what fertilizer your bed needs. If you can't test, then broadcast a time-released 13-13-13 fertilizer at a rate of 2 pounds per 100 square feet and till in.