Mandevilla Care Guide
Mandevilla spp.
Quick Answer
Most Mandevilla problems trace back to two things: insufficient light and inconsistent watering. It needs genuinely bright indirect light — not just near a window, but in the bright zone where you'd comfortably read without a lamp. Water when the top inch or two of soil is dry rather than on a schedule, and keep humidity above 50% for the best results.
⭐Difficulty
Moderate
☀️Light
Bright indirect to full sun
💧Watering
Every 5–7 days
🌫️Humidity
Medium (40–60%)
🌡️Temperature
50–90°F
📈Growth Rate
Moderate–Fast
Toxicity
Source: ASPCA Animal Poison Control
Watering
Summer
Every 5–7 days
Winter
Every 10–14 days
Method: Water when top inch is dry; water thoroughly; drain well; do not overwater — root rot is a concern; reduce significantly in winter
In summer, aim to water mandevilla approximately every 5–7 days; in winter cut back to around every 10–14 days. Rather than following a calendar, water when the top 1–2 inches of soil feel dry. Water thoroughly until water drains from the bottom, then don't water again until the soil passes the dryness check. Yellow leaves often signal overwatering; drooping with dry soil means it needs water now.
Light Requirements
Bright indirect to full sun
Mandevilla does best in a south- or west-facing windowsill where it gets at least 2–4 hours of direct sun. Without direct light, Mandevilla stretches toward the light source, loses its compact shape, and colour or markings may fade.
Soil & Potting
Soil: Well-draining potting mix with perlite
Pot: Any pot with drainage; provide a trellis or stake
Temperature & Humidity
Temperature: 50–90°F (10–32°C)
Humidity: Medium (40–60%)
Fertilizing
Frequency: Every 2 weeks in spring/summer with bloom fertilizer; skip fall/winter
Type: High-potassium bloom fertilizer
Common Problems
Yellow leaves
Yellow leaves: Overwatering. Let top inch dry before watering. Yellow leaves that start on the lower or older growth first usually point to overwatering. Check the soil — if it's wet, hold off entirely until it dries out properly. Less commonly, yellowing comes from low light, nutrient deficiency, or the natural ageing of older leaves.
No flowers
No flowers: Insufficient sun or wrong fertilizer. Move outdoors; use bloom fertilizer. Catching the problem early makes it much easier to fix — watch for early warning signs and act before the plant is in serious distress.
Spider mites
Spider mites: Very common in warm dry conditions. Treat with neem oil. Check under leaves and along stems regularly, since pests establish colonies before becoming visible from above. Treat with insecticidal soap or neem oil, covering the undersides of leaves, and repeat every 5–7 days for at least three rounds.
Milky sap irritation
Milky sap irritation: Wear gloves when pruning; avoid touching sap to skin or eyes. Catching the problem early makes it much easier to fix — watch for early warning signs and act before the plant is in serious distress.
Propagation
The easiest way to propagate Mandevilla is by stem cuttings. Take a 4–6 inch cutting that includes at least one node (the point where a leaf attaches). Remove any leaves that would be submerged, then place it in water or directly into moist potting mix. In water, roots appear within 2–4 weeks; pot up once they reach an inch long. The thing that trips people up most: taking a cutting without a node. Without a node, the cutting stays green for weeks but will never root.
Seasonal Care Calendar
🌸 Spring
Spring is when Mandevilla starts actively pushing new growth as day length and light intensity increase. Increase watering frequency as the plant becomes more active, begin fertilising every 2–4 weeks with a balanced liquid fertiliser, and this is the ideal window for repotting or taking cuttings.
☀️ Summer
Summer is peak growing season — Mandevilla is working hard and using water and nutrients faster than at other times of year. Water more frequently but check the soil rather than going on a fixed schedule, since heat and higher light accelerate drying. If you move it outdoors, introduce it to conditions gradually to prevent sun scorch.
🍂 Fall
Fall is a transition: Mandevilla grows more slowly as light levels decrease. Reduce watering frequency slightly, stop fertilising by late October, and move it closer to a window to compensate for shorter days. Avoid drafts from opening windows as temperatures drop. Watch for flower buds developing around late spring through fall — avoid repotting or relocating the plant at this time.
❄️ Winter
In winter, Mandevilla enters a slower-growth phase and uses water more slowly than in summer. Water less frequently to avoid root issues from soil staying wet too long in low light. If your home is heated and the air is dry, a pebble tray or humidifier keeps the plant comfortable.