Sally Scalera

Brevard County Horticulture Extension Agent
3695 Lake Drive -- Cocoa FL 32926 -- 321-633-1702

Ground cover produces food, too!

June 12, 2004

Every now and then you find a plant that accomplishes two things (at one time) in the landscape. Many ornamental plants also attract wildlife like butterflies, birds and hummingbirds. Some gardeners will only grow plants if they produce food but, as with citrus, they may also produce fragrant blooms. I have in mind today a very attractive ground cover that also produces food. he ground cover that I am thinking of is sweet potatoes (Ipomoea batatas).

When thinking of nutrition, many people already realize how nutritious sweet potatoes are. Sweet potatoes are packed with four times the U.S. Recommended Daily Allowance (RDA) of vitamin A and half the RDA of vitamin C. These are one of the healthiest vegetables you can harvest!

Even if you don't eat the skin of your sweet potato it still has a significant amount of copper, folic acid and fiber. The closest vegetables (nutritionally) to the sweet potatoes - and they are still far behind in overall nutritional value - are carrots, spinach and collard greens.

Do you have an area in your yard that is in full sun or partial shade and looking pretty bare? Would you like to cover that bare spot with an attractive ground cover and then later, be able to harvest some sweet potatoes? It's easy to do and now is the perfect time to get started. As long as the cold takes a long time in coming next winter your sweet potatoes will continue to grow. The plants are only damaged by frost.

Some garden centers sell slips (or rooted cuttings) of sweet potatoes in the late spring. You may not have a choice but recommended varieties for Florida include Porto Rico, Georgia Red, Jewel, Centennial, Coastal Sweet, Boniato or Sumor. If you want to start your own slips the fun and easy way then, just buy a sweet potato from the grocery store. Set the potato in a dish or vase. Keep one-third of the end or side covered with water and wait for growth to start on top. When shoots that are six inches or longer begin to form roots they can be snapped from the potato for planting.

Sweet potatoes grow in any well-drained sandy or organically amended soil. Space the plants 12-14 inches apart in a mass planting if you want them in the landscape or in rows four feet apart in the vegetable garden. Mulch the plants and then water them well twice a week. Give the plants a low nitrogen fertilizer, like 5-10-10, 2-12-12 or a similar fertilizer. Simply scatter the fertilizer among the vines and water the fertilizer in so none of the foliage gets burned.

You can begin harvesting the sweet potatoes in about 120 days but remember, you don't have to destroy the vine in the harvesting process. he sign that the sweet potatoes are ready for harvest is when the ground cracks around the base of the vine. The cracks indicate that the roots have swollen to edible size. If you want, dig a few to eat but leave the vines there so they will continue to grow and produce more potatoes. Sweet potatoes will develop underground everywhere the plant roots.

There are also some very attractive ornamental sweet potato vines that also produce edible roots. These cultivars are; 'Blackie', 'Margarita' and 'Tricolor'. In 1999 the FNGA picked 'Blackie' and 'Margarita' as a Plant of the Year. Blackie' has deep purple-red foliage. It produces dense mounds that stay low if planted in rich, moist soil. 'Blackie' prefers a little shade but will do well in full sun if it receives a constant water supply.

Edible roots with greenish-yellow flesh, a firm texture and a mild flavor will form later in the season. The 'Margarita' sweet potato has chartreuse green foliage. Light shade is best but plants that get plenty of water can take full sun.

'Tricolor' produces attractive variegated pink, white and gray-green foliage. Sometimes, 'Tricolor' is sold as 'Pink Frost'. This one grows slower then the other two cultivars. All of these plants produce edible sweet potatoes but you will want to visit a garden center to find these ornamental versions of the sweet potato.