A guide to when to prune trees

Acacia(Mimosa) After flowering and remove any
frost damage in spring
Acer (Maple) Winter
Aesculus (Hippocastanum)
Autumn until mid-winter
Albizia (Swamp Wattle) Spring
Alnus (Alder) Autumn until mid-winter
Betula (Birch) Late summer, before mid-winter
Carpinus (Hornbeam) Late summer, before mid-winter
Carya (Hickory) Autumn, early winter
Castanea (Sativa) Chestnut Autumn or winter
Catalpa (Bignonioides) Bean Tree Between autumn and late winter
Corylus (Colurna) Hazel Winter
Davidia (Handkerchief Tree) Autumn to early spring
(Flame Tree, Royal Poinciana)
Late winter, before new growth in spring
Embothrium Late summer 
Emmenoptery Between autumn and early spring
Euccalyptus (Gum Tree) Winter to spring
Eucryphia (X Nymansensis) Spring
Fagus (Sylvatica) Beech Autumn to early spring
Fraxinus (Excelsior) Ash Autumn and early spring
Gleditsia (Triacanthos) Late summer to mid-winter
Halesia (Carolina) Silver Bell,
Snowdrop Tree
Autumn to early spring
Hoheria (Populnea) Late spring
Ilex (Aquifolium) Holly Mid to late summer
Jacaranda Winter
Juglans (Nigra) Walnut Mid-summer, before mid-winter
Laburnum (Anagyroides)
Golden Rain
Late summer, before mid-winter
Lagerstroemia Autumn to early spring
Laurus (Nobilis) Bay train in spring before new growth,
shape in summer
Lindera (Praecox) Autumn to early spring
Luma Spring, before growth
Maackia (Amurensis) Autumn to early spring
Magnolia (Campbellii) Early to mid-summer
Malus (Baccata) Crab Apple Autumn to early spring
Meliosma Spring as growth begins
(Dombeyi) Southern Beech
Late spring
(Obliqua) Autumn to early spring
Oxydendrum (Sorrel Tree) Autumn and early spring
Platanus (X Acerifolia) Autumn to early spring
Plumeria (Rubra) Early spring
Populus (alba)  Late summer or early spring
Pyrus (Calleryana) Pear Autumn to early spring
Quercus (Cerris) Turkey Oak Autumn and early spring
Rhus (Verniciflua) Varnish Tree Late summer
Robinia (Pseudoacacia) Mid-late summer
Salix (Willow) Autumn to early spring
Sophora Summer
Styrax (Japonicus) Autumn to early spring
Tilia (Lime) Midsummer to mid-winter
Ulmus (Carpinifolia) Elm Autumn to early spring
Zelkova (Serrata) Late winter, possible light prune in
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