Hazel Catkins

The Common Hazel is a wind pollinated, monoecious tree.  A perfect flower, like those found on Cherry trees, has male and female parts combined but this can lead to self pollination so  some trees separate the male and female flower parts. If the separated parts are on the same tree it is known as monoecious (Greek for one household). Alder, Oak, Beech, Birch, Hornbeam and Sweet Chestnut are other examples of monoecious trees. 

Hazel catkins – the hazel is a monoecious tree with male flowers on hanging catkins and tiny female bud-like flowers with red stigmas. To see catkins on the closely-related Turkish Hazel click HERE

Hazel male catkin in February

The male flowers are on yellow catkins that hang down ready to release pollen onto the wind. There may be over 200 unisexual male flowers on a single catkin. 

hazel male catkin anthers

Each maleflower is covered by a scale which lifts when the catkin is ready to release pollen. Underneath each scale there are 4 pairs of green stamens full of pollen. The stamens split open to release pollen for wind dispersal when the conditions are suitable.


hazel male catkin anthers

Close-up showing the catkin after the pollen has been released and the stamens have turned brown. After pollen release, the male catkin soon drops off.

hazel female catkin

The  female flowers resemble a bud, with crimson stigmas that protrude when they are ready to receive pollen. The flower buds are located on the branch above the catkin, to avoid self-pollination.

hazel female catkin close-up

The female flower bud is shown in close-up in this photo. Each bud has several flowers. Each flower has 4 stigmas to collect pollen. If fertilised, each flower will produce  one nut, known as a cob.

hazel nuts or cobs

 One to four nuts are produced from one bud, depending on how many flowers were fertilised.