This species, although an introduction, has probably been in Britain for more than 100 years. Although it is often found on ornamentals including shrubs, increasingly it has been found to affect trees such as sweet chestnut and oak, attacking the roots and root collar. The disease it causes on sweet chestnut is known as ink disease because of the blackish colour of infected roots and associated soil.
Phytophthora cinnamomi is favoured in continental climates, so is most frequently found in south east England. It is considered sensitive to frost, but despite this there are records of this species as far north as Scotland.