What is a mandevilla?
Mandevilla (Mandevilla sanderi), sometimes sold as Dipladenia, is a vigorous twining vine from the dogbane family native to tropical South America. It’s best known for its showy, funnel-shaped flowers that bloom in vivid shades of red, pink, white, and bicolor from late spring through the first frosts of autumn. Given a sunny spot and a trellis, obelisk, or hanging basket to spill from, it blooms almost non-stop — making it one of the most rewarding warm-season container plants available in garden centers.
How much light does a mandevilla need?
Mandevilla is emphatically a full-sun plant — it needs at least 4–6 hours of direct sun per day to produce its signature flowers. In a partially shaded spot it will stay green but bloom sparsely. Indoors, a south- or west-facing window is ideal; outdoors, a sunny patio or balcony rail where it can soak up the afternoon sun is perfect. If you’re growing it under glass in winter, a supplemental grow light will keep it from going completely dormant.
How often should you water a mandevilla?
Water every 7–10 days during active growth, allowing the top inch of soil to dry out between sessions. Mandevilla sits at the crossroads of two failure modes: overly dry soil leads to bud drop and wilted growth, while waterlogged soil causes root rot fast. A free-draining, slightly gritty mix (standard potting soil amended with perlite) and a pot with drainage holes are non-negotiable. Ease off to every two to three weeks in winter when the plant is resting.
How do you get a mandevilla to bloom?
Three things drive flowering. First, maximum sun — anything less than four hours of direct light daily and bud production drops sharply. Second, the right fertilizer — during the growing season use a bloom-boosting formula with a higher middle number (phosphorus) rather than a nitrogen-heavy general fertilizer, which pushes leaves over flowers. Third, warmth — mandevilla stops blooming below about 60°F (16°C), so keep it in a warm spot and bring it inside before cool nights set in.
Can you overwinter a mandevilla indoors?
Yes. Before the first frost, cut the vines back by about a third, move the plant indoors to a bright, warm spot, and reduce watering to once every two to three weeks. It will likely drop some leaves and rest through winter; that’s normal. Resume regular watering and feeding when you move it back outside in late spring once nighttime temperatures stay above 50°F (10°C). Many gardeners successfully overwinter the same plant for several years this way.
Is mandevilla toxic to pets?
Mandevilla is not on the ASPCA’s toxic-plants list, but as a member of the Apocynaceae family it produces a milky latex sap that can cause mild gastrointestinal symptoms — drooling, vomiting, or diarrhea — if leaves or stems are chewed by cats or dogs. It is best treated as mildly toxic and kept out of reach of pets and small children as a precaution.