Horticulture/Hamamelis

Witch-hazel (Hamamelis) is a genus of four species of flowering plants in the family Hamamelidaceae, with two species in North America (H. virginiana and H. vernalis), and one each in Japan (H. japonica) and China (H. mollis). They are popular ornamental plants, grown for their clusters of rich yellow to orange-red flowers which begin to expand in the autumn as or slightly before the leaves fall, and continue throughout the winter. Numerous cultivars have been selected for use as garden shrubs, many of them derived from the hybrid H. × intermedia Rehder (H. japonica × H. mollis).

The Parrotia, a closely related tree formerly treated as Hamamelis persica, is now given a genus of its own, as Parrotia persica, as it differs in the flowers not having petals. Other closely allied genera are Parrotiopsis, Fothergilla and Sycopsis (see under Hamamelidaceae). Witch-hazels are not closely related to the hazels.

Hamamelis species are used as food plants by the larvae of some Lepidoptera species including Feathered Thorn.

Description
They are deciduous shrubs or (rarely) small trees growing to 3–8 m tall, rarely to 12 m tall, with gray bark that varies from smooth to warty in texture. The leaves are alternately arranged, oval, 4–16 cm long and 3–11 cm broad, with a smooth or wavy margin. Winter vegetative buds are foliose, floral buds on short stalks, opening slightly several weeks before fully blooming. The flowers have four slender, strap-shaped petals 1–2 cm long, pale to dark yellow, orange, or red. The fruit is a two-parted capsule 1 cm long with two "beaks" at the tip of each half, containing a single 5 mm glossy black seed in each of the two parts; the capsule splits explosively at maturity in the autumn about 8 months after flowering; the seeds are ejected with sufficient force to fly for distances of up to 10 m.

Ecology
Flowers of the winter-blooming species are visited by many insects, including bumblebees, and so can serve as an important nectar source at that time of year.

Culture and Use
Witch hazels grow best in full sun, but tolerate considerable shade. Deep, fertile, well-drained soils are best, but they are quite adamptable.

Witch hazels should not be pruned in mid to late winter, as they bleed copiously and the plant may become desiccated.

On many plants, the leaves fail to fall off the plant in autumn, and may need to be cut off with scissors since the dark brown dead leaves detract from the flower display of winter-blooming types.

The bark and leaves are astringent, the extract, also referred to as Witch Hazel, is used medicinally. Extracts from its bark and leaves are used in aftershave lotions and lotions for treating bruises. The seeds contain a quantity of oil and are edible.

Arthropod pests

 * ../Aphids/:
 * Spiny Witch Hazel Gall Aphid: ../Hamamelistes spinosus/
 * Witch Hazel Leaf Gall Aphid: ../Hormaphis hamamelidis/


 * ../Scale Insects/
 * Walnut Scale: ../Quadraspidiotus juglansregiae/


 * ../Bugs/:
 * Alder Spittlebug: ../Clastoptera obtusa/


 * ../Caterpillars/:
 * Leafroller: ../Argyrotaenia quercifoliana/
 * Blotch Leafminer: ../Camereria hamameliella/
 * Yellownecked Caterpillar: ../Datana ministra/
 * Saddled Prominent Caterpillar: ../Heterocapma guttivitta/
 * Eastern Tent Caterpillar: ../Malacosoma americanum/
 * Blotch Leafminers: ../Phyllonorycter/ spp.

Mammal pests

 * ../Squirrels/ eat the fruits, and occasionally bite off the branch tips to get the sap.
 * ../White-tailed Deer/ are uninterested in this plant.

Diseases

 * ../Powdery Mildew/ caused by Podosphaera biuncinata
 * ../Leaf Spots/ caused by Gonatobotryum maculicola, Monochaetia monochaeta, Mycosphaerella sp., Phyllosticta hamamelidis, or Ramularia hamamelidis
 * Wood rots