Corylus avellana
Corylaceae
Cob-nut
January to March
It is found throughout the country.
See the BSBI distribution map for Hazel
It is widespread in woods, scrub, hedgerows, on river
banks and cliffs, and is widely planted in copses and
hedges, round fields and alongside country paths.
Hazel is a native shrub or small tree, growing up to 6m.
The male flowers are numereous in pendulous, yellow
catkins up to 8cm. Each flower has small oval bracts and
4 stamens with yellow anthers..
Female flowers are bud-like spikes up to 4mm across. They
have a single ovule, 2 styles and a tuft of bright red linear
stigmas (see below).*.
Male catkins tend to appear before female flowers.
Hazel is wind pollinated.
Flowers appear before the leaves.
The fruits are edible nuts encased in a woody husk.
Leaves are up to 12cm, suborbicular, cordate at the
base, weakly serrate, strongly veined and petiolated.
Young twigs are covered in reddish-brown glandular hairs.
Hazelnuts are good to eat if the squirrels don't get
there first.
Hazel is grown commercially in Turkey and North
America with the nuts sold for eating, especially at
Christmas, and used in the manufacture of praline,
chocolate truffles and flavoured coffees.
* ScienceDaily, 13 February 2025.
.It has been shown that the red stigmas in wind-pollinated
trees accumulate anthocyanin, the same compounds that
are revealed in autumn leaves after green chlorophyll
production slows down. The anthocyanin supports pollen
germination and growth by acting as an antioxidant.
Wei-Hao Wang et al.(2025) Molecular Biology and
Evolution, DOI: 10.1093/molbev/msaf040
.Genetic mechanisms and adaptive benefits of
anthocyanin-red stigmas in a wind-pollinated tree.
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Hazel tree with male catkins in January
Male catkins
Male flowers with 2 bracteoles and 4
emerging anthers
Male flowers with ripe anthers and
bracteoles
Male and female flowers
Female closed flower bud and newly
open flower
Female flowers with linear stigmas
above the ovules
Close-up of linear stigmas
Hazel fruits - nuts
Closer view of Hazel nuts
Hazel leaves
Petioles with hairs
Glandular twig
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