Maple, a genus of deciduous deciduous trees and shrubs.

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recognize Sycamore
Sycamore, photo: Willow - CC BY 2.5
  • The “maple keys” (samaras) of the Common Maple are poisonous to horses

Maple(Acer), a genus of deciduous deciduous trees and shrubs, belonging to the maple family (Aceraceae). There are about 120 species and are found in the temperate regions of the northern hemisphere. Field maple (Acer campestre) and Sycamore (Acer pseudoplatanus) are native to central, eastern and southern Europe.
Maples are known for their fall colors.
A Maple can grow into a tree thirty feet tall and fifteen feet wide.
Maples like nutritious, loose soil, although they will also settle for poor soil.
The fruit of the maple consist of a nut with two wings (samara).
Pruning maple trees is not really necessary, however, sometimes intersecting branches need to be cut away or the crown thinned a bit. Because the maple, like grapes and beeches, bleeds from pruning wounds when the tree is not at rest, major pruning is best done in the months of July and August, when the maple is in full growth and pruning wounds will recover quickly. The same applies to pruning Japanese maple trees (Acer palmatum, Acer dissectum): prune in the summer.
Maples are susceptible to pests from Aphids and gall mites. Mildew is also relatively common.


Aphids on the leaves. Sometimes these secrete honeydew on which sooty mold forms.

recognize galls on maple tree
Galls on maple leaf, photo: BJ.schoenmakers – CC0

Galls (+ 2mm) where the veins of the leaves cross, ranging from green to reddish brown. Sometimes hairy: Maple pimple gall mite (Aceria spp.).

recognize scale insects on maple (Acer)
Cottony Hydrangea Scale on Japanese maple, photo: Sandra Marijnes

White woolly waxy fluff with wax threads: Cottony Hydrangea Scale (Pulvinaria hydrangeae). The lint is in fact the egg sac of the insect.

recognizing horse chestnut scale
Horse chestnut scale on maple tree, photo: Cwmhiraeth – CC BY-SA 4.0

Brownish aphids populate the stem: Horse chestnut scale (Pulvinaria regalis).

Fungi & diseases

recognize spots maple leaf
Black spots on top of maple leaf, photo: Annabel – CC BY-SA 3.0

Black spots on the leaves: tar spot (Rhytisma acerinum).

recognize fungus on maple
Gray, powdery fungus on Spanish bark, photo: Frank Vincentz / CC BY-SA 3.0

Gray, powdery fungus on top of leaves: variants of powdery mildew (Ascomycete strain).

The leaves of young trees suddenly wilt, dry up and die. Eventually the young maple dies: Verticillium wilt (Verticillium spp).

recognize damage soot bark disease
Sooty bark disease on maple tree, photo: bjoerns – CC BY-SA 4.0

Dark brown to black spots on the bark, early leaf fall and dried branches in the crown: sooty bark disease (Cryptostroma corticale).

Recognize coral spot
Coral spot, photo: Pethan – CC BY-SA 3.0

Small, orange-red raised spots appear on affected branches, which can be either dead or living branches: Coral spot (Nectria cinnabarina).

Recognizing fungus on trees
Lacquered bracket, photo: Chmee2 – CC BY-SA 3.0

Mushroom formation on trunk: fan-shaped fungus, shiny orange/brown top. The spores are found as cocoa-like powder around the fungus. The fungus can grow half a meter wide on old, large trees: Lacquered bracket (Ganoderma resinaceum).


Maples have a thin bark, which can cause the bark to burn in hot weather and lots of sun.