Corylus is
a genus of around 10 species of deciduous trees and shrubs from
temperate woodland regions. They have alternate, rounded or oval
leaves. As bonsai, most forms of Corylus are considered to have
too large and coarse leaves to be displayed during the growing
season. However, after leaf-fall, their rugged bark and catkins
make for excellent winter displays. During the late-Summer and
early Autumn, Hazels produce edible nuts.
In Europe it is Corylus avellana / Common Hazel
that is most frequently seen as bonsai. This is an upright tree-like
shrub to 5metres in height with broadly heart-shaped, toothed,
mid-green leaves to 10cm long. During the winter, it bears small
pendant yellow catkins to 4cm long which remain on the tree until
early Spring.
Corylus avellana 'Contorta' / Corkscrew Hazel
is a form that has naturally twisted growth creating an excellent
twisted and distorted trunk and branch structure. (The 'twisting'
habit is due to a naturally occurring virus that does no harm
to the tree other than to create accelerations in growth unevenly
across the width of a shoot. This results in new shoots that cannot
grow straight and true.
Corylus species
are related to Birches and are members of the same broad family
Betulaceae, other 'Hazels' such as Winter Hazel / Corylopsis species
and Witch Hazels / Hamamelis species are not closely related (though
of a similar appearance) and are members of the Hamamelidaceae
family.
