Know where your plants come from
When plant material is moved around from one country to another, either through importing or exporting, or people bringing in samples and cuttings, there is a risk of importing pests and diseases.
There are several diseases which are putting some of our common garden trees and shrubs at risk and which it pays to be aware of:
Ash die back
One of the most common plant diseases that most people are now aware of is Ash ‘die back’ which was imported into this the UK in 2012 and is now widespread and causing major damage. Signs your trees have this are black blotches appearing on the leaves, lesions on the bark of stems and branches and extensive dieback of shoots, twigs and branches.
However, there are a couple of other diseases lurking just over the channel that you may not be aware of which have the potential to cause a great deal more damage and which we should all work together to keep out:
Xyella fastidiosa is a bacterial disease which attacks a wide range of plants including lavender, rosemary, olives and some oak species. This list is increasing weekly as more host plants are found. Any outbreak in this country could lead to the destruction of all potential host plants within 100 metres of the infected plant and a potential quarantine zone with a radius of up to five kilometres for five years! So far in Europe there have been outbreaks of this disease in Italy, France, Germany and Spain, and it is moving northwards.
Xanthomonas arboricola pruni
Another bacterium is Xanthomonas arboricola pruni which causes severe holing in leaves and canker of the stems, which often die back. Xanthomona attacks a wide variety of cherries and laurels (Prunus species) and has the potential to do serious damage to the plum and cherry crop in the UK if imported. This disease is not to be confused with common Shot Hole in laurel, which is native to this country and just causes some minor damage from which the plants grow out of.
At present neither of these diseases are in this country, and legal controls are set to be imposed on the imports of potentially risky species. However, these have yet to be implemented and legislation alone will not be sufficient to protect our woodlands and gardens in the UK from the potentially devastating effects of these diseases.
What you can do to prevent these diseases entering this country:
The first thing is to keep calm and carry on planting. However, when buying planting stock ask your supplier to confirm that their plants have come from an area free from the diseases (at present the UK is completely free of these diseases and so UK grown plants are best).
Our Yorkshire grown stock is completely clear of imported diseases and with a totally auditable production trail. Not only this, since our nursery is situated in a frost pocket in North Yorkshire, you can be confident that our stock is guaranteed to be hardy.
For further information on these diseases please go to the Department for Environment Food and Rural Affairs website:-