Rhododendron – Rhododendron Ponticum

Rhododendron ponticum is an evergreen, hardy shrub which is so easy to grow in the right lime-free conditions that it has become naturali7ed in many of our woodlands, and people often think of it as a native wild plant, although in fact it was introduced from Spain and Asia Minor. With its natural height of up to 6 m (20 ft), and its spread of 9 m (30 ft) or more, it makes an effective informal hedge or screen. Its purple and pink flowers are borne in June.

General care: Plant in March, in lime- and chalk-free soil which has got some humus or compost in it, adding leaf mould or hop manure if necessary. Rhododendrons are surface-rooting, and must have some moisture-retaining material in the topsoil. Set the plants 90 cm (3 ft) apart if for a hedge, and 1.5 m (5 ft) apart or more for a screen, depending on the thickness of the screen required. Water on planting, and keep up the water if the first spring is dry. R. ponticum needs no pruning, apart from any trimming necessary to keep it in shape, which should be done in the winter. Deadhead the flowers to stop the seeds forming, unless they are needed for propagation.

Rhododendron - Rhododendron Ponticum

Propagation: Seeds harvested when they are ripe should be sown the following spring in pots or pans of soil-less compost. Alternatively, layer some long shoots any time in the summer.

Pests and diseases: Rhododendron bud blast turns the flower buds brown or black in the autumn. Control is by killing the carrier, the rhododendron leaf hopper, by spraying with fenitrothion in August. Leaf-yellowing caused by chlorosis means that your soil is too alkaline to grow rhododendrons. You can try making it more acid by adding quantities of peat.

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