Day of the Rhododendron

Programme Outline

The programme describes the fight in Snowdonia National Park (Parc Cenedlaethol Eryri) against Rhododendron Ponticum, a species which has spread wildly since its introduction as an ornamental plant in Bodnant Gardens, a well-known stately home situated in the National Park. If left unchecked, the plant largely eliminates other plants and reduces the ecosystem to a monoculture.

The importance of the preservation of biodiversity is emphasised. The programme describes in detail some features of the rhododendron plant that enable it to propagate so effectively, such as its wind-borne seed dispersal and its efficient photosynthesis, and some features which limit opportunities for control. The fight to contain the plant is graphically shown.

00.00 - 03.38 Introduction

The spread of Rhododendron Ponticum across hillsides in Snowdonia National Park is an ecological problem.

03.38 - 05.45 Where did the invasion start?

First introduced by early plant collectors, the plant has spread from Bodnant Gardens.

05.45 - 07.20 Seed propagation in Rhododendron Ponticum

Each plant produces millions of seeds which are dispersed over large distances by the wind.

07.20 - 08.29 Underground attack

A symbiotic relationship between the roots and a certain fungus produces a toxin that poisons other species and thus reduces the degree of biodiversity.

08.29 - 12.34 Photosynthesis

Rhododendron Ponticum can photosynthesise in very low light levels, and produces a dense covering that prevents other plants from growing, leading very rapidly to a monoculture.

12.34 - 13.41 Methods of control

Physical methods of cutting and burning are not enough, and the plant even has a defence against chemical methods of control.

13.41 - 16.01 Defence against chemical poisoning

Unlike most plants, Rhododendron Ponticum does not have many cross-paths between phloem vessels, and so unless herbicides are sprayed onto all branches, some of the plant is likely to survive, and will need to be resprayed.

16.01 - end Summary and review of key points

In some areas where Rhododendron Ponticum has been cleared, oak trees are beginning to flourish and biodiversity is increasing.