Mandevilla × amabilis is a tropical twining vine in the Apocynaceae family, widely sold under the cultivar name Alice du Pont. It produces large, rose-pink, trumpet-shaped flowers continuously from late spring through fall, with bold glossy foliage that stays ornamental between flushes. It is one of the most commonly grown ornamental climbers for warm-climate gardens and seasonal patio containers.
The vine performs best in full sun with fertile, well-drained soil and consistent moisture during the growing season. Feeding with a balanced or high-phosphorus fertilizer every four weeks drives steady reblooming. In zones 9b–11 it grows as a woody perennial and can reach 15 ft or more on a sturdy trellis or arbor. In frost-prone zones it is treated as a tender seasonal vine or moved indoors before the first frost, overwintering in a bright, cool location with significantly reduced water. All parts contain a milky sap that irritates skin and is toxic to pets and children if ingested; wear gloves during pruning.
Powdery mildew
White or grey powdery coating on leaves - usually starting on older growth in humid conditions or when nights cool.
Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.
Root rot
Plants wilt, yellow, and stunt even in moist soil; lower stems and roots turn brown, soft, and mushy and the plant may collapse. Most common in heavy, wet, or poorly drained ground.
Improve drainage and stop overwatering, and never plant too deep. Lift and destroy badly affected plants along with the soil around the roots. Grow in raised or free-draining beds to prevent it returning.
Crown Rot
Lower leaves yellow and wilt; the base of the rosette turns brown and soft, sometimes with white fungal threads at the soil line. Plants collapse in wet conditions.
Remove and destroy affected plants. Improve drainage and avoid overhead watering. Do not mulch directly against the crown. Space plants for airflow and avoid replanting in the same wet spot.
Fungal leaf spot
Brown or purplish spots on the leaves, often ringed with a yellow halo, that spread and merge in warm, humid, or wet weather; heavily spotted leaves yellow and drop early.
Pick off spotted leaves and clear fallen debris to remove overwintering spores. Improve air circulation by thinning, and water at the base so foliage dries quickly. If it persists, apply a copper- or sulfur-based fungicide at the first sign.
Botrytis (grey mould)
Grey fuzzy mould on petals and stems, worst in cool wet conditions.
Remove affected parts immediately. Improve air circulation. Avoid overhead watering. Apply copper fungicide if severe.