Mandevilla
Mandevilla sanderi
also called dipladenia, rocktrumpet
A summer climber that has to come in before the nights reach 10°C, then sit barely awake until spring.
- Type
- Shrub · Perennial
- Botanical family
- Mixed / other
- Foliage color
- Green
- Flower color
- Pink
- Sunlight
- Full sun to bright indirect light.
- Watering
- Water freely through summer, sparingly in winter.
- Feeding
- A high-potash feed every week or two through the growing season.
- Frost tolerant
- Yes
- Flowering
- May
- Pruning
- Prune hard in early spring, before growth starts.
- Overwintering
- Bring it in before 10°C, then keep it barely moist at 10-15°C.
- Apr–May Spring Growth
- May–Oct Flowering
- Oct–Nov Growing
- Nov–Dec Dormancy
- Jan–Apr Dormancy
- Plant spacing
- 3 ft 3 in
- In-row spacing
- 3 ft 3 in
- Between rows
- 4 ft 1 in
- Square-foot density
- Not suited to SFG
- Root system
- Swollen storage roots
- Working depth
- 8–20 in
- Can reach
- 3 ft down where the soil allows
- Spread
- 3.5–5 ft across, about 1–1.5× the width of the plant
- Shallowest pot
- 14 in of soil
The fat roots are the larder and the thin ones do the feeding. Lift them or mulch them deeply where the ground freezes hard, and handle them by the crown: a snapped storage root rots rather than heals.
A tuberous root that will overwinter dry and dormant in a frost-free shed, which is how a mandevilla is kept from year to year where it cannot stay outside.
The habit is Mandevilla’s own; the figures are what that habit usually comes to at this size, not a measurement of this species. Roots follow the soil either way: a compacted pan, a high water table or heavy clay stops them well short of any of it, and deep open ground lets them go further.
Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. companion plant
- Ladybird (lady beetle) Coccinellidae
The gardener’s favorite ally: adults and their alligator-shaped larvae each eat thousands of aphids, plus scale, mealybugs, and other soft-bodied sap-suckers. Grow flat, open flowers for the adults and never spray a colony that ladybird larvae are already working.
- Big-eyed bug Geocoris spp.
A stubby 3 mm bug with enormous wrap-around eyes, working the soil surface and the low foliage for aphids, mites, thrips and insect eggs. It is the main natural check on chinch bugs in a lawn and it is killed outright by insecticide.
- Green lacewing Chrysoperla carnea
Its bristly larvae — "aphid lions" — impale aphids, mealybugs, thrips, and mite colonies, eating hundreds a week. Adults feed on nectar and pollen from small open flowers and overwinter in hollow stems left standing.
- Minute pirate bug Orius spp.
A pinhead-sized true bug that is the best natural check on thrips, and happily spears aphids, mites, and insect eggs too. It needs pollen when prey is scarce, so keep something flowering nearby.
- Dragonflies & damselflies OdonataHunts Whitefly
Aerial hunters that take mosquitoes, midges and small flies on the wing all day, and whose larvae spend a year or more clearing the same insects from the water. A pond with planted margins and no fish is the way to have them.
- Hoverfly SyrphidaeHunts Scale insects
Bee-mimicking flies whose legless larvae graze aphid colonies clean while the adults pollinate. A ribbon of shallow, nectar-rich flowers kept in bloom all season recruits wave after wave of them.
- Parasitic wasps Braconidae & TrichogrammaHunts Whitefly
Tiny, stingless wasps that lay eggs in or on caterpillars, aphids, and moth eggs — the white cocoons riding a hornworm are their calling card, so leave that caterpillar be. Umbel flowers with shallow nectar keep the adults fuelled.
- Predatory mites Phytoseiulus & AmblyseiusHunts Spider mites
Fast orange mites that hunt spider mites egg-by-egg, and cousins that clear thrips and fungus-gnat larvae. Sold as a biological control for greenhouses; outdoors they follow humidity — mist and mulch, don’t dust with sulfur.
- Rove beetle StaphylinidaeHunts Spider mites
Slim, quick beetles with short wing cases that hunt in soil and litter, taking root-fly eggs and larvae, fungus-gnat larvae, and mites. Mulch and undisturbed ground keep them resident year-round.
- Spiders AraneaeHunts Whitefly
Webs, ambushes, and night patrols make spiders the garden’s steadiest generalist predators, taking whatever flies or crawls past. Mulch, ground cover, and undisturbed corners keep the population dense.
Green-leaved shrubs with pink flowers, like this one.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com