by George Papadelis
American gardeners have made huge strides in their efforts to reproduce the incredible combinations of color, form, and texture produced by the English. Gardeners have put less and less focus on flowers, and more on interesting foliage. This shift has made certain plants extremely popular lately. Among the annuals, silver has become a staple. Dusty miller and especially licorice plant are in higher demand than ever before. Among the silver perennials, lamium and lamb’s ear (the non-blooming form), for shade and sun respectively, are priceless in any combination. The multicolored leaves of annuals like Caladium, Phormium, and coleus make incredible accents in both beds and containers. This month’s featured plant is readily available to provide you with beautiful gold or black foliage. Ipomoea batatas ‘Margarita,’ golden sweet potato vine, has large, heart-shaped leaves of chartreuse that grow on vigorous trailing vines. In contrast, Ipomoea batatas ‘Blackie,’ has blackish burgundy leaves on vigorous trailing vines. These vines will not climb, they will only trail. In the past 2 or 3 years, more and more gardeners have relied on these for an easy-to-grow, black- or gold-leafed, cascading plant.
Sweet potato vines are extremely versatile and easy to grow. I have seen very happy plants in the full sun and heat of North Carolina, as well as in planters with impatiens in full shade. They are not prone to pest or disease problems, and once established, they are tolerant of both wet and dry conditions. The common name is accurate; plants will produce edible sweet potatoes. Although they are almost always grown from cuttings, gardeners are always surprised when removing plants in the fall, since a large potato will have developed below the soil. This can be stored and propagated the following spring, but most gardeners find this difficult and will usually acquire fresh, new plants.
Use the gold sweet potato in contrast with purple foliage or flowers. Rose, pink, or blue flowers will also work. For bedding, try the bright purple, pink or rose flowers of trailing verbena for a tapestry of bright foliage and flowers. In containers, add verbena and a vertical flower component such as the blue, spiked flowers of Salvia farinacea. For vertical foliage, try the dark foliage of New Zealand flax (Phormium), a sort of fancy-leafed spike, or the metallic purple, silver, and green foliage of Persian shield (Strobilanthes).
The black-leafed sweet potato looks great with anything bright. Silver or gold foliage is perfect, and bright yellow, pink, rose, or magenta flowers are great as well. Try the silver foliage of licorice plant or the trailing silver leaves of Artemisia ‘Silver Brocade.’ This perennial looks like a sort of trailing dusty miller whose foliage glows in contrast to the large black leaves of Ipomoea batatas ‘Blackie.’ For bright flowers, use trailing verbenas, yellow lantana, or petunias.
When trying to develop these sweet potato combinations, try making a little “bouquet” in your hand with the elements you are considering. This is a great way to predict how your creation will look when complete. Remember that these are very versatile plants so the possible combinations are numerous. And with the hundreds of interesting and attractive plants now available in both perennials and annuals, you are sure to create a hit. It’s hard to err when using reliable, showy foliage like that of the sweet potato vine.
Sweet Potato Vine
Botanical name: Ipomoea batatas
Plant type: Annual (tender perennial treated as an annual)
Plant size: Height: low, trailing Length: up to several feet
Habit: Low-growing, trailing, cascading
Hardiness: Zone 9 (where it can be grown as a perennial)
Leaf color: Chartreuse (‘Margarita’); dark burgundy (‘Blackie’); green, white and pink (‘Pink Frost’)
Leaf shape: Heart-shaped (‘Margarita’); maple-like (‘Blackie’); arrow-shaped (‘Pink Frost’)
Leaf size: 2-5 inches across
Light: Full sun, partial shade
Soil: Well-drained, moderately fertile
Uses: Containers, hanging baskets
Companion plants: Many annuals and perennials; experiment with both similar and contrasting colors
Remarks: Grown for its cascading habit and attractive foliage, especially to contrast with companion plants
George Papadelis is the owner of Telly’s Greenhouse in Troy, Michigan.