Language English Trees and Shrubs Hydrangea quercifolia Photo: Robert Mineau OngletsBotanyOrigin and description This small shrub (1.5 m x 1.5 m) with a rounded growth habit produces large leaves shaped similarly to oak leaves. Dull green in summer, in the fall they turn red, purple and orange. Flower heads form in pyramidal panicles consisting of tiny fertile flowers and large white sterile florets which often turn purple. Species, cultivars and related plants ‘Snow Flake,’ ‘Snow Queen,’ ‘Little Honey,’ ‘Snow Giant,’ ‘Pee Wee,’ ‘Sike’s Dwarf’. Toxicity All parts of the plant are poisonous. Common nameOakleaf hydrangeaLatin name (genus)Hydrangea quercifoliaFrench common name Hydrangée à feuilles de chêne Botanical familyHydrangeaceae HorticultureGrowing conditions Lighting conditions Sun or partial shade. Soil Rich, cool and well drained. Hardiness and protection Barely hardy in our climate, choose a site sheltered from winter winds, where snow accumulates, but does not melt too quickly in the spring (east or north side of the foundation). Although the roots will survive in Zone 5, stems and flower buds are susceptible to frost (Zone 6), especially during a cold winter without snow. If there is a frost, new shoots will spring from the roots but they will not flower. In the fall, the stems must be protected under a thick layer of shredded-leaf mulch (30 cm). In spring, the mulch should remain in place until the end of the spring frosts. Small cultivars (‘Sike’s Dwarf’) are most likely to flower because they winter under the snow. Pruning and maintenance The flowers bloom on old wood, so prune lightly. Pruning too heavily (coppicing) will prevent flowering in that year. In the fall, just cut the stems that have flowered back to a pair of healthy buds and cover with mulch. In spring, prune to remove any stem sections damaged by the cold. HardinessZone 5Zone 6See also Cultivating hydrangeas (Hydrangea spp.) Climbing hydrangea Climbing hydrangea Mountain hydrangea Mountain hydrangea Hortensia Hortensia Panicle hydrangea Panicle hydrangea Pests and diseases Hydrangea Leaf-tier The hydrangea leaf-tier (Exartema ferriferanum) is a small moth that lays its eggs on the branches in either the fall or the spring. Upon hatching, the small green black-headed caterpillars sew two terminal leaves together with silk thread, forming an enclosure in which they feed.