23 August 2024

Growing Wild: Haws and Powdery Mildew on Whitethorn

Catherine Keena, Teagasc Countryside Management Specialist, takes a closer look at some of our native Irish biodiversity, focusing this time on Haws and Powdery Mildew on Whitethorn.

Haws on Whitethorn

Look out for haws on whitethorn and note where they are occurring – on older wood. Treeline hedges where whitethorn has grown into single stem trees with full canopies full of haws at this time of year. Topped hedges with occasional whitethorn trees, which have been allowed grow within them provide haws on those trees. At Hedgerow Week events on Teagasc farms in Ballyhaise, Athenry, Clonakilty, Curtins Moorepark and Kildalton at 11am on 2 – 6 September respectively – see where whitethorn saplings have been selected in recent years from within existing old hedges and allowed grow up and mature as individuals to flower and fruit – an easy way to increase our native Irish biodiversity in topped hedges.

Topped hedge

Powdery Mildew on Whitethorn

Look out for powdery mildew on whitethorn hedges. The white powdery coating on the leaves is a disease but plants will out-grow this. Farmers appear to be more aware of diseases on newly planted hedges because of the fireblight scare and are relieved when powdery mildew is diagnosed. It may be more prevalent on topped hedges protected with compostable film, or hedges in drier conditions, as powdery mildew does not like wet conditions. There is no need to worry or do anything. Learn more at Hedgerow Week events on Teagasc farms in Ballyhaise, Athenry, Clonakilty, Curtins Moorepark and Kildalton at 11am on 2 – 6 September respectively – promoting native Irish biodiversity.

Powdery mildew on recently planted whitethorn hedge