It can be quite tricky to mimic the native growing conditions of golden trumpet plants as indoor specimens. Indoor Allamanda flowering vine needs structural support for the rambling stems. You can keep it pruned for a more compact plant. Good care of Allamanda golden trumpet starts with the planting medium. Use a potting soil with equal parts peat, compost and sand. Golden trumpet houseplants need four hours or more of direct bright sunlight.
Water deeply until the excess moisture runs out of the drainage holes but then wait until the top surface of the soil dries out before you irrigate again. Allamanda doesn’t like wet feet. Fertilize in spring through summer every two to three weeks with a good blooming plant food. Allow the plant to rest in winter. Suspend fertilizing in winter as part of good Allamanda plant care. Restart fertilizing in April and move the plant outside as soon as temperatures are above 60 F. (16 C.). Prune in early spring and cut stems back to pone to two nodes to promote tighter new growth.