Common diseases that could be affecting trees in your garden

Five common tree diseases that can be found in the UK

Homeowners have been warned of five common tree diseases that can be found across woodlands and gardens in the UK that could damage or even kill trees on their properties.

Arboriculturists from Arbtech have shared their expert advice on the symptoms to lookout for, including wilting leaves, damaged bark, and discolouration.

Whilst conservation efforts are in place, tree diseases can have a devastating impact on the landscape and the biodiversity of our woodlands.

There are a number of different diseases that are widespread across the UK and affecting many different species of trees in both woodlands and gardens.

Amongst the common diseases are Ash dieback, a potentially fatal disease which is predicted to wipe out almost 80% of the UK’s ash populations, and Dutch elm disease, the killer of millions of elm trees across the UK over the past 50 years. *

Symptoms for ash trees suffering with Ash dieback include dark patches developing on leaves during the summer months, before wilting and discolouring to black where leaves might also shed early.

Similarly for Dutch elm disease, symptoms can also be seen in the leaves, as diseased elm trees will consist of clusters of yellow leaves that wilt and fall.

Other common tree diseases in the UK include Acute oak decline, Horse chestnut bleeding canker, and Phytophthora ramorum. 

Since homeowners with a tree on their property have a legal duty to ensure the safety of their neighbours, it is important that trees in the garden are not left to be unsafe through damage or disease, as this may leave them liable if it causes any damage to a property or person.

It is recommended that tree owners have regular tree surveys completed by qualified arboriculturists to ensure the ongoing safety of any trees on the property.

A spokesperson from Arbtech said: “Tree disease can unfortunately have a devastating impact across our tree populations in the UK.

“As well as the impacts it has on the biodiversity and landscape of our woodlands, trees in your garden could also be at risk so it’s important to look out for the different symptoms.

“Since homeowners have a legal duty to ensure the safety of their neighbours, it’s really important that you have regular tree surveys completed by qualified arboriculturists so trees aren’t left to be unsafe.

“Having your trees looked at by a professional can help to determine the best course of action, and early intervention is key.

“And before undergoing any work to trees in your garden, make sure to check with local planning authorities in case the tree has any protections in place.”

Five common tree diseases in the UK and their symptoms:

Ash dieback

A devastating disease that can affect ash trees of all ages, with younger trees succumbing to the disease more quickly. The common symptoms to look out for include dark patches developing on leaves during the summer months, leaves wilting and discolouring to black, diamond-shaped dark brown lesions developing where the branches meet the trunk, and a brownish-grey colour to the inner bark under the lesions.

Dutch elm disease

A disease that has killed millions of elm trees across the UK over the past 50 years after it was accidentally imported from Canada in the late 1960s. Some of the common symptoms to look out for include clusters of yellow leaves that wilt and fall, dark streaks underneath the barks of twigs, shoots that die back from the tip, and twigs that bend down into a shape described as a “shepherd’s crook”.

Acute oak decline

The current decline in the UK has been observed for the past 20 years, with trees that are over 50 seemingly worst affected, and mature trees can die within 5 years of getting the disease. If you’re the owner of an oak tree, the symptoms to look out for include the general thinning of the crown as leaves are lost, cracks in the bark, and dark fluid and extensive weeping patches that can seep through vertical cracks in the bark.

Horse chestnut bleeding canker

This can affect trees of all ages, where some infections can last for years with little impact, while some can spread rapidly and sometimes cause death of part or even the whole tree. The symptoms include cracks in the bark that can ooze a dark or reddish-brown liquid, discoloured wood under the bark that could have patches of brown or purple, and dead bark might even fall away on older cankers.

Phytophthora

Phytophthora is a genus of fungus-like organisms that has many different species and can affect many types of plants including trees and shrubs. Two species in particular that have had an impact in the UK include Phytophthora ramorum, which has had a devastating impact on larch plantations, and Phytophthora kernoviae, which has been particularly damaging to beech trees. Symptoms of Phytophthora ramorum include areas of black “bleeding” on the trunk, whilst Phytophthora kernoviae symptoms include bleeding cankers on oak and beech tree trunks.