©BSNHS 2014

 The foliage is a food source for insects both monophagus and polyphagus species, with 209 phytophagus insect species recorded feeding on Hawthorn. From pollen data Hawthorn arrived here around 7000 years ago.

This month its got to be Common Hawthorn or May (Crataegus monogyna another Rosaceae member.)  

A very common native tree, although a pioneer species often invading grassland, readily found in woods and hedgerows growing to around 6m in height as a shrubby tree. Here in Hatfield Forest towards the west of the lake (TL54102016) an old pollard has been recorded at 16m in height.

Usually flowers appear in May, although with the mild winter some trees are flowering a few weeks earlier than normal, though these are possible hybrids - Common Hawthorn hybridising with the Midland Hawthorn (Crataegus laevigata).

Flowers are abundant in corymbs of about 5 - 16 or more buds, which are globular, opening white with five petals one style (whereas the Midland Hawthorn usually has two styles). Heavily scented, attracting a wide variety of non specialised insect pollinators such as midges, flies, wasps, butterflies, moths and bees.

The red fruits ripen late August or September and may remain on the tree until the following Spring.  An important food source for mammals and birds especially winter visitors - Redwings and Fieldfares - but also our resident birds Thrushes, Blackbirds and Wood pigeons. Mistle thrushes have been recorded in defending individual trees for its fruit.   Birds are an important factor in seed dispersal, which then take 18 months to germinate.

Helophilus pendulus sunning itself

Hawthorn leaf galled by Phyllocoptes goniothorax

May Tree of the Month - Common Hawthorn