Ornamental · Convolvulaceae
Ornamental Sweet Potato Vine
Ipomoea batatas
Warmth, bright light, and constant moisture set this vine unrolling a low blanket of chartreuse to near-black leaves over every rim it meets.
Full sun
Every 2–5 days
50–95°F · 10–35°C
USDA 9–11
Overview
Ornamental sweet potato vine wears its color in the leaves, not the roots. It is the same species as the food crop, Ipomoea batatas, bred instead for bold foliage that ranges from a bright chartreuse to a purple dark enough to read as near-black. The leaves crowd along trailing stems that pour over a pot rim or bed edge and knit into a low, dense sheet of color.
The stems stay short-jointed and hug close to the ground, holding the whole plant to just inches tall while it runs outward. It grows across hardiness zones 9 to 11 and is treated as an annual where it turns colder, flushing new leaves fast once the soil warms and blackening at the first hard cold. A single plant spreads its stems 8 to 10 feet (2.4 to 3 m) wide, which is why it drapes so far over walls and pot rims.
Leaf shape shifts by cultivar, from deep-cut lobes to a plain rounded heart, and the surface is smooth and matte. Flowers appear only now and then, small funnels in pale pink to violet, but the foliage is the whole point, and it is the leaves that carry the plant from spring until the cold.
Care
The short version: full sun to a little shade, evenly moist soil rich in organic matter, and warmth above frost. Feed it through the season, trim the trailing stems whenever they overrun their space, and grow it as an annual where winters bite.
Light
In full sun the leaves reach their deepest color, though the plant takes partial shade without complaint. The dark-leaved kinds keep their inky purple only in strong light, and under shade the blades fade toward green.
Water
Soil kept evenly moist holds the leaves firm and flat, and once the roots are down the vine bears a dry spell. Containers dry out fastest, and the leaves wilt as a clear watering cue, folding soft, so check pots in full sun every couple of days through summer.
Soil
Set the roots in loamy, well-draining soil worked full of organic matter. A slightly acidic pH of 5.5 to 6.5 suits it, and the loose drainage keeps the roots from sitting wet.
Temperature
The leaves push fastest in the warmth between 50°F and 95°F (10°C to 35°C) and stall in the cold. Frost blackens the foliage outright, so the vine cannot stay out through a freeze.
Humidity
Average outdoor humidity is plenty, and there is no number to hit. The vine carries muggy summer air on its leaves without trouble, though moving air keeps fungus off the surfaces.
Feeding
Feed every two weeks through the growing season with a balanced water-soluble fertilizer to keep new leaves unfurling. A high-phosphorus starter at transplanting pushes the young roots into strong early growth.
Pruning
Cut the trailing stems back anytime in the growing season to check the spread and keep the mound of leaves tidy. The stems take a hard cutback in stride and flush new growth quickly.
Size & spacing
The plant holds a low mound just 6 to 12 inches (15 to 30 cm) tall while its stems reach 8 to 10 feet (2.4 to 3 m) across. Give the stems room to run or trim them, since one plant blankets a wide stretch of ground in a season.
When to plant
The soft, leafy growth depends on warmth and blackens at the first frost. Start tubers or cuttings indoors a few weeks before the last frost, set the plants out once the soil has warmed in late spring, and let the stems run until cold weather ends the season.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Not typically started from seed; start tubers or root stem cuttings indoors 4 to 6 weeks before the last frost.
- Plant: Set out plants after all danger of frost has passed and soil has warmed in late spring.
- Harvest: Grown for foliage; rarely flowers (pale pink to violet funnel-shaped blooms). Tubers can be dug in fall before first frost.
Hardiness
USDA hardiness zones: 9–11
Temperature: down to -7°C
Troubleshooting
Trouble on this vine shows on the leaves first, whether the blades go limp with thirst, mottle under a fungus, or tear where something has been feeding. Most of it is cosmetic and easy to head off. Match what you see below and act before it spreads.
Discolored patches and dark speckled blotching across the leaf blades
Dark specks and irregular blotches break up the smooth leaf surface, and these are fungal leaf diseases. They spread where the vine goes back into the same ground year after year and the foliage packs in humid and crowded. Stripping off the spotted leaves, opening the planting so air moves across the surfaces, and shifting to fresh ground the next season returns the leaves to clean color.
Fix:
- Remove and discard affected foliage
- Improve air circulation and avoid overhead watering
Leaves going limp on a hot afternoon
The leaves that hung out firm and flat go soft and folded, and this is drought stress rather than disease. It shows first in pots baking in full sun, where the plant drinks faster than the soil can supply. A deep watering until it runs from the drainage holes lifts the drooping foliage, and more frequent watering keeps container leaves turgid through the hottest weeks.
Fix:
- Water thoroughly until it drains from the bottom
- Increase watering frequency for containers in full sun
Ragged, hole-punched blades flecked with pale stippling
Torn holes and a fine pale speckling pit the once-smooth blades, the work of flea beetles, thrips, and slugs. Tiny jumping beetles chew the holes, thrips rasp the dusty stippling into the surface, and slugs drag glistening trails across the leaves. Hand-picking or trapping the slugs, treating the beetles and thrips, and clearing the leaf litter that hides all three keeps the foliage whole.
Fix:
- Hand-pick or trap slugs
- Monitor and treat flea beetle and thrips populations as needed
Toxicity
Good news for pet owners: this vine is safe. The ASPCA lists Ipomoea batatas as non-toxic to cats, dogs, and horses, and its leaves and stems pose no threat to rabbits, livestock, birds, or people. The tubers underground are even edible, just blander than the kinds grown for eating.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Cats are safe around it. The ASPCA lists Ipomoea batatas as non-toxic, so a curious nibble on a leaf will not poison them.
Dogs None
The stems and leaves hold no toxic compounds, and the ASPCA clears it for dogs. A dog that chews a trailing vine takes no harm.
Horses None
Horses can graze near the foliage without harm, since the ASPCA rates the plant non-toxic to them.
Rabbits Safe
Nothing in the leaves or stems threatens rabbits, so a bite taken from a trailing shoot causes no trouble.
Livestock Safe
Cattle, goats, and sheep can be around the leaves and stems without risk, since the plant carries none of the toxins that worry farmers.
Birds Safe
Pet and backyard birds are in the clear. The foliage holds no compounds that would harm them.
People Safe
The leaves and stems are harmless to handle and grow around children. The tubers underground are even edible, just less tasty than the kinds bred for the kitchen.
Varieties
The differences come down to leaf color and leaf shape. These are the cultivars you will see most often.
Blackie
Its leaves are deeply lobed and cut into fingered points, colored a purple so dark it reads as near-black.
Margarita
Its broad heart-shaped leaves glow a bright chartreuse-green.
Sweet Caroline Group
Its leaves run green, red, or dark purple and take either a finely divided or a rounded heart shape.
Tricolor
Its green leaves are variegated, splashed and edged with pink and white.
How to propagate
This vine multiplies with almost no effort, either from cuttings of the leafy stems or by splitting the swollen tubers stored over winter.
Stem cuttingsEasy
Take 8 to 10 inch cuttings from vigorously growing terminal or middle vine sections in the warm growing season. · Roots typically develop in about 4 to 5 weeks.
Cuttings root readily from the succulent stems. In the warm growing season, 8 to 10 inch lengths snipped from the leafy tips or the middle of a vine sit in water or moist soil, where pale white roots push from the nodes in about 4 to 5 weeks. The rooted cuttings go outdoors once frost has passed.
DivisionEasy
In spring after last frost, divide stored tubers into sections. · Several weeks to sprout and establish.
The stored tubers split into pieces in spring once the last frost has passed. Each swollen tuber is cut so that every section keeps at least one eye, the small bud that pushes up a new shoot, and the pieces go into outdoor soil. They take several weeks to sprout and settle in.
Myths
Its family ties to the morning glories make sweet potato vine poisonous to animals.
The ASPCA lists Ipomoea batatas as non-toxic to cats, dogs, and horses. The toxic-seed danger belongs to the ornamental morning glories, Ipomoea tricolor and I. violacea, whose seeds carry LSA and other indole alkaloids. Sweet potato vine shares the family name, not the danger.
The fleshy tubers that form under ornamental vines are inedible to humans.
The fleshy tubers under the ornamental cultivars are edible. They simply taste blander than the kinds bred for the dinner table, so the plant is grown for the leaves overhead rather than the roots below.