Rhododendron Frequently Asked Questions

What is Rhododendron?

Rhododendron is a non-native species introduced to Britain during the late 18th century. Originally sought after for its ornamental aesthetics, Rhododendron quickly became a common sight in Victorian gardens and estates providing excellent cover for game birds such as pheasants. Today, Rhododendron can be found growing nationwide, in both countryside and urban areas.

What does Rhododendron look like?

Rhododendron species vary in size but can grow to heights of 8 metres and form a dense, impenetrable mass of thick interlaced branches and tough, waxy leaves. Many species of Rhododendron feature clusters of brightly coloured flowers which can produce thousands of seeds.

Why is Rhododendron a problem?

A combination of large seed banks and the ability for its branches to take root when in contact with the ground enables Rhododendron to spread and rapidly colonise the surrounding area. The dense foliage cover of the plant will starve any local vegetation of light and deny them the opportunity to develop, enabling Rhododendron to continually spread from season to season unhindered. There have been cases of Rhododendron colonies stretching across bodies of water, using horizontal growth to spread while remaining firmly rooted along the shoreline.

What damage can Rhododendron cause?

Biodiversity in an area where Rhododendron is present can be significantly impacted. The blanketing of thick branches and leaves will shade natural light from other neighbouring species and eventually growth and reproduction is halted under the lightless canopy. Plants that otherwise would have become home to hundreds of species of mammals, birds and insects had it not been for the presence of Rhododendron are no longer able to survive. It has been known for entire areas to be abandoned for future development due to the presence of Rhododendron. These impassable living barriers deny access and render ground unusable if established growth is not controlled. Several species of Rhododendron are toxic and can poison grazing animals unfortunate enough to consume them.

How can you kill Rhododendron?

Successful control and elimination of Rhododendron can be a time-consuming and costly undertaking. The use of herbicides can often be ineffective due to the thick waxy leaves of the plant preventing full chemical absorption and can often take several years before progress can be made. Mechanical means of control such as digging or cutting of Rhododendron will have varied degrees of success depending on experience and equipment used. Re-infestation of ground previously affected by Rhododendron can be a risk due to the possibility of dormant seeds and must therefore be taken into consideration if control is to be attempted.

How can I prevent Rhododendron spreading?

The relentless spread of Rhododendron can be very difficult to prevent due to the huge number of wind dispersed seeds produced and the rooting of branches contacting ground level. The methods of control described above are the most likely means of preventing further growth of Rhododendron; regular cutting back of existing foliage may slow the spread but will not be a long term solution.

Can I plant Rhododendron?

There is no law against the planting of Rhododendron on private property but due to its highly invasive nature it is not advisable to do so especially in close proximity to property boundaries. Whereas you may be more than happy with your Rhododendron, your neighbour might not be if it spreads into their land!