Merlin's Magic Dipladenia

Merlin's Magic Dipladenia (Mandevilla sanderi 'Rosea') is the flowering climber for a hot courtyard where nothing has room to sprawl. It twines to about 1.5m tall and 1m wide, small enough for a pot and a slim trellis, and carries deep pink trumpet flowers in flushes from spring through to autumn. Unlike the larger mandevillas it stays compact and keeps flowering without constant tying in.

Why you'll love it

• Months of flower, not weeks. Pink trumpets open in repeated flushes from spring to autumn, heaviest through the warm months.
• Compact for a climber. At 1.5m by 1m it suits an obelisk or a balcony railing rather than swallowing a fence.
• Heat and humidity are no problem. It is South American and genuinely enjoys a hot, sticky summer, which few flowering climbers manage.
• Drought tolerant once settled. Established plants cope with dry spells, although potted plants still need regular water.

Where it works best

Pots, balconies and courtyards. A 400mm pot with an obelisk is the classic use. Growing it in a container also lets you move it under cover, which matters in any garden that gets frost.

Poolside planting. It drops very little litter compared with most flowering shrubs, handles reflected heat off paving, and sits the flowers at eye level along a pool fence.

Feature planting in small gardens. Trained up a post or a wall mounted wire, one plant becomes a vertical run of colour in a bed too narrow for a shrub.

Growing dipladenia in Australia

Position and climate. Full sun gives the heaviest flowering, with afternoon shade acceptable in the hottest inland gardens. This is a tropical, subtropical and warm temperate plant, and it is frost tender. In cool temperate gardens grow it in a pot and shift it under cover for winter.

Soil. Free draining above everything else. Use a quality potting mix in containers, and open up heavy garden soil with compost and coarse sand. Cold wet roots over winter are the usual cause of loss.

Water and feed. Water when the top few centimetres of mix dry out in spring and summer, then cut right back in winter. Liquid feed every two to three weeks through the warm months.

Pruning. Tip prune young growth to force branching, and cut the plant back by about a third in early spring. Flowers form on new wood, so that spring cut drives the season ahead. The stems bleed a milky sap, so wear gloves.

What to expect when it arrives

It is sold in 200mm pots in packs of six and 140mm pots in packs of ten. The 200mm plants are more advanced, already twining and often carrying buds in the warmer months. The 140mm plants are younger and better value per plant across a long balcony.

Climbers travel with their stems tied in, and some leaf drop after transit is normal. Give each plant its support within a week of arrival, because unsupported stems twine around each other and are awkward to separate later. Delivered Australia wide, with delivery from $29.95. Every plant carries our 30 day healthy plant guarantee.

Plant care guides and related reading

• Browse the full climbing plant range
• Choosing low maintenance poolside plants
• Compare plants for poolside gardens
• Plants that perform on a balcony

Common questions

Is dipladenia safe around cats and dogs?

No. The stems and leaves carry a milky sap that is toxic if chewed and irritating to skin, so keep it out of reach of pets that graze on foliage. Wear gloves when you prune.

Will it survive frost?

It is frost tender, so an unprotected plant in a cold garden will be cut back or killed by a hard frost. In cool temperate districts treat it as a container plant and move it under a verandah for winter.

Does it need a trellis?

Yes. It twines rather than clinging, so it needs something slim to wrap around. It will not attach itself to a flat wall or a paling fence without help.