Ontario Weeds: European
buckthorn
Table of Contents
- Name
- Other Names
- Family
- General Description
- Stems and Roots
- Leaves
- Flowers and Fruit
- Habitat
- Caution
- Similar Species
- Related Links
Name: European buckthorn, Rhamnus
cathartica L.,
Other Names: nerprun commun, Common
buckthorn, nerprun purgatif, nerprun cathartique
Family: Buckthorn Family (Rhamnaceae)
General Description: Perennial, reproducing
only by seed. Grows as a bushy small tree or several-stemmed shrub
up to 6 m (20 ft) high.
Photos and Pictures
European buckthorn (A - flowering branch;
B - branch with black berries)
European buckthorn.
Stems & Roots: Most branches
older than one year are tipped with a short, sharp thorn, (hence
"thorn" in its English name); this thorn often present
in the fork of 2 branches.
Leaves: Leaves usually opposite (2
per node), but sometimes alternate (1 per node), elliptic or oblong
usually with fine rounded teeth but sometimes nearly smooth, dark
green above and lighter green or yellowish-green below; usually
with 3 main branching veins (sometimes 2 or 4) on each side of the
midrib that strongly curve or arch forward towards the tip of the
leaf.
Flowers & Fruit: Flowers small,
with 4 sepals and 4 petals, greenish to yellowish, short-stalked,
in small clusters from the axils of leaves or on short twigs along
the stem; each flower unisexual with either 4 stamens or 1 pistil
but not both, and the sexes usually on different plants; berries
round, 5 - 6 mm (1/5 - ¼ in.) in diameter, purplish-black
and very juicy with 4 very hard seeds (stones). Flowers during May
and June but the berries, and often the dry leaves, persist on the
tree long into winter.
Habitat: European buckthorn was introduced
as an ornamental shrub, but its seeds have been widely scattered
by birds and other animals so it is common in fence lines, woodland,
pastures and abandoned farmyards throughout southern Ontario.
Similar Species: It is distinguished by
the sharp, thorn-tipped branches in contrast to the simple or compound
thorns growing from the sides of branches in the Hawthorns, by the
prominent forward-curved side veins of the leaves, the clusters
of purplish-black berries along the stems and short twigs, and each
berry usually with 4 hard seeds.
Caution: Because European buckthorn is
an alternate host for the fungus which causes leaf and crown rust
of oats, it must be destroyed to minimize this disease on oats.
The juicy berries are very bitter and cathartic, and usually cause
severe stomach cramps if eaten.
Related Links
... on general Weed
topics
... on weed identification, order OMAFRA
Publication 505: Ontario Weeds
... on weed control, order OMAFRA
Publication 75: Guide To Weed Control
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