Tree Guide: Alder

Alder Alnus glutinosa

Deciduous

Up to 20 metres tall

(rarely to 40 metres)

 Leaves to 10cm long, elliptical or almost circular; dark green and hairless

Flowers in catkins, appearing before leaves from January to March

Fruit cone-like, woody and egg-shaped

Alder Moth

Acronicta alni

Forewing length 16-19mm

Adults May-June

Larva June-August

Overwinters as a pupa

 
 

May Highflyer

Hydriomena impluviata

Forewing length 13-16mm

Adults May-early July

Larva July-October

Overwinters as a pupa

Alder Sawfly

Eriocampa ovata       

                               

 

Size 10mm

Adults May-August