Family: Oleaceae
Common Name: Ash

Found throughout the northern hemisphere, except in the coldest regions and the tropics, this genus comprises around 65 species of deciduous trees, many very ornamental, and making beautiful park and street trees. Some of the species are valued for their tough, pale timber. They all have pinnate leaves, most of which colour beautifully before falling, and winged fruits, called samaras. Masses of tiny flowers appear before the leaves open. Flower structure divides the genus into two sections, but this does not concern the gardener.

Species

F. americana, white ash, zone 3, is a magnificent tree which is highly valued in its native habitat of North America. It reaches heights of 15-30 m (50-100 ft) and has a long, straight trunk. The leaves comprise seven to nine long, lance-shaped, dark green leaflets, paler on the undersides, which change to a pur­plish colour before falling. Useful as a specimen tree, it yields valuable hardwood timber used for many purposes.

F. augustifolia, narrow-leaved ash, zone 6, is a popular tree in drier cli­mates, as it tolerates very dry, almost desert, conditions. It is a handsome tree, to 25 m (80 ft) tall. Cultivar Raywood = 'Flame', claret ash, is a hardy tree, 6-10 m (20-33 ft) tall. Its attractive foliage colours superbly in autumn to a deep coppery red, even in lowland areas.

F. excelsior, common ash or European ash, zone 4, grows 30-40 m (100-130 ft) tall in its habitat, although around half this size in culti­vation. It has a rounded canopy, making it a lovely shelter or specimen tree for large gar-dens. It has distinctive, black buds from which both the leaves, comprising nine to eleven leaflets, and flowers emerge. The timber is well suited to carpentry. As an ornamental it is hard to better the golden ash, F. excelsior 'Aurea'. The twigs and small branches are yellow and the lime to yellow foliage becomes deep gold in autumn.

F. ornus, manna ash or flowering ash, zone 6, grows 7-15 m (23-50 ft) tall, with gray buds and long, slightly toothed, sharply pointed leaflets. In late spring it is covered in sprays of strongly perfumed, dull white flowers, borne at the tips of the branches. The sweet sap, or 'manna' (not the 'manna' referred to in the Bible), was once used as a laxative.

Cultivation

Fraxinus will grow in most soils, even limestone soils, but prefers a well-drained, sunny position, though it will tolerate partial shade. Being deciduous, it is best to plant in late autumn or early winter. Propagate from stratified seed sown in spring, except for F. excelsior 'Aurea' and F. angustifolia Raywood = 'Flame', which should be budded onto the seedlings of F. angustifolia or F. americana in the early summer.

Climate

There are species suited to various cli­matic zones.