Plant Doctor Archive

Rhodo won't flower

I HAVE had a Rhododendron yakushimanum and a gardenia for four years now and they have never flowered. I fertilise them with the azalea, camellia, rhododendron fertiliser and spray with Sequestrene, but still no flowers. Can you help?

BOTH these plants generally flower at an early age as long as they are healthy, and it sounds as if you are doing most things right in that regard. The question is, are they setting flower buds that fail to open or are no flower buds being initiated?

If the plants are growing well but lack flower buds, then simply cutting out the fertiliser to slow growth and encourage flowering may do the trick. But don't be tempted to cut the plants back as you may remove shoots with potential flower buds. The ideal time to prune rhododendrons is immediately after flowering, but yakushimanum types seldom need pruning. Never prune them in winter as you'll remove the shoot tips that flower in spring.

Similarly, don't prune gardenias unless absolutely necessary, such as to reduce legginess. Unlike the rhododendron, gardenias need to be in a very warm spot to get good flowering - though the variety 'Fragrant Star' is said to flower well in relatively cool conditions.

Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.