Acer carpinifolium (Hornbeam Maple)


Michael's Opinion

A small tree rarely seen in the landscape, at least in my experience but well worth inclusion in the garden. A rounded form looking more like a hornbeam in leaf than a maple, however it has significant autumn colour and interesting seed.

Botanical Information

FamilySapindaceae (Aceraceae)
GenusAcer
Speciescarpinifolium
CategoryWoody
TypeTree (deciduous)
OriginJapan.
Pronunciation

Details

USDA Hardiness Zone4 - 7
USDA Hardiness Ref.
Canadian Hardiness Zone2a - 6a
Canada Hardiness Ref.
RHS Hardiness ZoneH5 - H7
RHS Hardiness Ref.
Temperature (°C)(-34) - (-15)
Temperature (°F)(-30) - 5
Height6 - 8 m
Spread6 m
GrowthMedium
Flowering PeriodMay

Description and Growing Information

General DescriptionIt is a small tree with un-maple-like qualities, ie. multi-stemmed, entire leaves and drooping clusters of seed. This species has been placed on the IUCN Red List as least concern.
ID CharacteristicHornbeams are easily identified by their lobeless, ovate-oblong leaves that are un-maple like; they look like the true hornbeams (Carpinus). The leaves form hairs upon emergence in the spring and turn a brownish gold in the autumn. The bark is smooth and grey in colour, very similar to some species of Carpinus.
ShapeVertical in shape, it is dense and low branched.
LandscapeThe hornbeam maple is a small tree and is a suitable addition to a mixed perennial garden or for use as a patio tree because of its size, although this tree is not commonly found in nurseries.
PropagationRipe seed is best sown immediately in a cold frame and will germinate the following spring with no pre-treatment. Nursery seed should be pre-soaked for up to 24 hours followed by 2-4 months of cool stratification at a temperature of 1-8°C; the seed is slow to germinate.
CultivationHornbeam maple grows best in moist, well drained soils that are sandy-loamy or gritty-loamy in character. It prefers partial sun, but does well in full sun.
PestsNo serious pests, although they may be prone to aphids, borers and caterpillars. Verticullium wilt, leaf spots, tar spots and root rot are also potential diseases.
Notable SpecimensThe Niagara Parks Botanical Gardens, Niagara Falls, Ontario, Canada. Westonbirt, The National Arboretum, Tetbury, Gloucestershire, England.
Bark/Stem DescriptionThe bark is smooth and grey in colour.
Flower/Leaf Bud DescriptionThe bud is normally brown but occasionally a reddish colour with the scales imbricate.
Leaf DescriptionThe leaves are 7 - 15 cm in length and 3 - 6 cm in width. They are simple, lobeless, broad and pinnately veined with a serrated margin and 18 - 24 pairs of veins.
Flower DescriptionThe plant is dioecious and produces racemes which flower in May with green, five-stellate flowers.
Fruit DescriptionThe fruit is a samara, approximately 1 cm in length.
Colour DescriptionDark green throughout the spring and summer, brownish gold in the autumn.
Texture DescriptionFine in texture.

Photographs