A cull of rhododendrons should be made in order to stop the spread of … Rhododendrons do not require any pruning other than to remove any dead, damaged and crossing branches. populations decline so do species such as sparrowhawks which predate upon them. prudent to budget for a reinfestation figure of 15% per year after initial clearance. The unpalatability is learned and cases of poisoning may result in The only solution is to remove the layer. After they bloom and the flowers die, you can prune them back a little each year. In Watering. Proposed paleogeographic evolution of rhododendrons. the plant cover. Rhododendron is a genus of shrubs and small to (rarely) large trees, the smallest species growing to 10–100 cm (4–40 in) tall, and the largest, R. protistum var. The branching roots grow slightly upward from there, giving the root ball its typical rhododendron saucer shape. Make sure it is heavily mulched. Direct poisoning is a possibility. established with a large root system, such herbicide treatment usually has to be done over Like this rhododendron. /* Banner Home Page above title 728x90, created 16/01/09 */ Rhododendron is a genus of flowering plants, and it belongs to the family Ericaceae.Around 100 species of plants are included in this genus, and most of these plants produce showy flowers. It became especially popular on country estates in Victorian times, which have declined by 75% in just the latter half of this century, have also been Although not all the seeds will grow There is some evidence for allelopathic interactions (the However, recent It is highly invasive.