Grow and Care for Allamanda

Grow allamanda in full sun and heat, in soil that drains. Allamanda is a tropical evergreen in the dogbane family — golden trumpet is the yellow climber most tags mean. Frost kills it, so most of the country grows it as a summer plant or a pot you bring inside.

Give it full sun, warm nights, and soil that drains

Allamanda wants full sun and heat. It takes plenty of water during the growing season, but the soil has to drain. [1] Tie a climber from day one. golden trumpet does not twine and does not make tendrils, so a floppy vine is a training miss, not a different plant. Match vine or bush on Types of Allamanda.

Water when the top dries, and feed while it blooms

Allamanda blooms on new shoots in summer and fall if the root zone stays moist — not soggy — and you feed while it is growing. Let the surface dry slightly between waterings so the mix can take air. [2]

1. Water deeply until excess runs out of a pot, or until the root zone of a bed is wet several inches down.
2. Wait until the top of the mix feels dry, then water again. Do not keep the mix wet all week.
3. Feed every two to three weeks from spring through bloom with a fertilizer labeled for flowering plants.
4. Stop feeding in late summer as nights cool, so the plant can rest instead of pushing soft growth into frost.

A long dry spell drops flower buds. A wet pot in cool weather rots the roots. Water to the weather, not to a fixed calendar.

How to plant allamanda

1. Wait until nights stay reliably warm — about 60°F or higher — before you plant out or move a pot outside.
2. Dig a hole as deep as the root ball and two to three times as wide. Set the plant at the same depth it grew in the pot.
3. Backfill with the original soil mixed with a little compost. Water to settle. Do not bury the stem. Space a shrub about three to five feet from its neighbor. [3]
4. Tie a climber to a trellis or fence the same day. A bush allamanda can skip the tie if you are keeping it as a shrub.

Bring it in before frost, then cut it back in spring

Allamanda is frost-tender. A light freeze strips the leaves; a hard freeze kills the plant. In a frost-free yard it can stay in the ground. Everywhere else, treat a pot as a plant you move. Flowers form on the new shoots that follow a spring cut, so do not strip that wood in late summer if you still want bloom.

1. Move a container inside when nights drop toward 40°F. Do not wait for the first freeze on the forecast.
2. Give it the brightest window you have. Cut watering back and stop fertilizer so the plant can rest.
3. In spring, just before new growth starts, cut stems back to one or two nodes. Flowers form on the new shoots that follow.
4. Move the pot back outside only after nights stay warm, and harden it off in increasing sun for a week so leaves do not scorch.

You can also grow it as a summer annual and replace it the next year. That is simpler than forcing a dim indoor winter.

Not a mandevilla — and not a hardy trumpet vine

Allamanda is not mandevilla. Shops sometimes label a pink mandevilla as pink allamanda; that plant is a different genus, and its care lives on How to Grow Mandevilla. Allamanda is also not hardy trumpet vine. The orange climber that survives a cold winter is Campsis, covered on How to Grow Trumpet Vine. Golden trumpet is the yellow Allamanda in this cluster.

How to start allamanda from a cutting

Take a cutting in late spring if you want another plant. Half-hardened stems — stems that have started to firm — root more reliably than soft new tips or old woody canes.

1. In late spring, cut a half-hardened stem and strip the lower leaves. Wear gloves; the milky sap irritates skin.
2. Stick the cutting in a mix that drains. Bottom heat helps roots form.
3. Cover the pot so the air stays humid until the stem resists a gentle tug. Then grow it on in full sun and heat like the parent plant.

Keep it in sun and heat through the bloom season, and move the pot inside before a freeze — those two jobs decide whether allamanda flowers instead of rotting or frosting out.