Mandevilla

About Mandevilla

Mandevilla is a tropical twining vine with glossy evergreen leaves and big trumpet-shaped flowers in pink, red, white and yellow. It's a summer favorite for mailboxes, trellises, patio pots and hanging baskets, and hummingbirds and butterflies visit the flowers (NC State; UF/IFAS). Plants once sold as Dipladenia now belong to Mandevilla; newer kinds are bushier and need little support. Outside frost-free areas it's grown as a summer annual or brought indoors for winter.

Survives winter outdoors only in zones 10-11, where it can bloom all year (UF/IFAS); everywhere else grow it as a summer annual or overwinter it indoors.

When to plant

Timing is counted from your average last spring frost (and first fall frost). Sow & Tell works out the actual dates for your ZIP code.

Set out nursery plants after frost danger has passed and nights stay warm; it grows best around 65-70 F (NC State). Give vining kinds a pole, wire or trellis to twine on, and in very hot, humid areas some afternoon shade (NC State, UF/IFAS). To keep it, bring it in before nights regularly fall to the low 50s F (UMD): grow it on in a bright, cool room around 55 F with extra humidity, or cut it back to about 12 inches and let it rest near 50 F in a frost-free garage or basement, watering only now and then (NYBG, MU Extension). Days to first bloom aren't documented; nursery plants are usually sold in bloom.

Soil

Moist, well-drained soil or potting mix; it handles sand, loam or clay as long as water drains away (UF/IFAS, NC State).

Use a well-drained potting mix or loose garden soil; it tolerates sand, loam or clay if water drains away (UF/IFAS).

Feeding

• Spring through summer, while it's growing and blooming: balanced or water-soluble fertilizer. UF/IFAS advises regular watering and regular feeding through the growing season; follow the label rate, especially in pots.
• Late winter or spring, when an overwintered plant puts out new growth: water-soluble houseplant fertilizer. Hold off feeding through winter, then start again once new growth appears and move it to a sunny spot (UMD).

Don't keep it soggy indoors; let the soil dry out somewhat in winter (NC State), and don't feed while it rests (UMD).

Harvest

Blooms most heavily in summer, and all year in zones 10-11 (UF/IFAS). Pinch the shoot tips of young plants for a bushier, fuller vine, and wear gloves when you prune because the milky sap can irritate skin (UF/IFAS, NC State).

Varieties (11)

Extension sources document these 11; breeders now favor shrubbier kinds. Yellow-flowered vines sold as 'yellow mandevilla' are a different plant (Pentalinon luteum) per UF/IFAS.

Pests to watch for

Aphids, Twospotted spider mite, Thrips, Whiteflies, Mealybugs, Scale insects

In the kitchen

Safety: The milky sap can irritate skin and may be toxic if swallowed (UF/IFAS). Wear gloves when pruning, and don't eat any part.

Pets: Not listed by the ASPCA (no mandevilla entry). UF/IFAS warns the milky sap may be toxic if swallowed, so keep pets from chewing it.