It’s maintenance time for rhododendrons

Rhododendrons need relatively little maintenance throughout the year and you might think that in winter you could forget about them completely. However, there are several important tasks to bear in mind that can help optimise both health and flowering in the coming season.

Winter is a good time to prune out dead wood to reveal the sinuous branching structure of larger rhododendrons and, at the same time, any suckers on grafted varieties should be removed to prevent competition with the variety grafted above.

Competing growth from adjacent plants can also be dealt with along with herbaceous stalks or long grass matted around the stems or collapsed over smaller rhododendrons.

Shading from overhead trees can also be reduced to increase light and air flow as spring returns to increase flowering and reduce disease.

While doing all this, any bare areas can also be identified for mulching in spring. In colder areas be ready with frost cloth to protect more tender and early flowering varieties.

Soil renovation and border development are the more intensive tasks for winter to revitalise areas in decline or needing a makeover. Installing drains, digging over and forking-in gypsum to aid soil structure can all be considered to help open up the soil and improve vigour.

From here comes the opportunity to devise a whole new planting scheme.

All these strategies have been used in the Rhododendron Dell at the Dunedin Botanic Garden over the years to ensure fresh and attractive displays.

Garden Life is produced by the Dunedin Botanic Garden.

For further information contact Doug Thomson.