Ulmus

Ulmaceae

Elm

Deciduous trees, leaves typically turn yellow in autumn, flowers are small and red appearing before leaves, and the green fruits are disc shaped and winged.
 

Uses

Specimen tree, large garden tree, coastal garden tree, shade tree, windbreak. 
 

Culture

Elms thrive in exposed sunny aspects in most types of soil. They do not require pruning. A number of species, notably the Wych Elm or Scotch Elm (U. glabra) are tolerant to salt winds. 

Propagation

Named cultivars are commonly grafted on seedlings; seed needs stratification (period in cold) to induce germination  They can be propagated from suckers which should be potted or kept in nursery beds and then planted out after 2 years. Weeping forms are usually grafted onto U. glabra rootstock in summer. Autumn layering will yield new plants after two years.

Cultivars

Cultivars include:

U. glabra (syn. U. Montana; Wych Elm, Scotch Elm): One of the few trees which can be planted near the sea in full exposure to sea gales. It is a large spreading tree to 9m with an oval head. The leaves which emerge on short stalks are obovate and toothed, with a rough surface, and appear as mid green turning yellow in winter. Dense fruit crops appear in spring. It is capable of reproducing readily from seed.

U. minor (syn. U. carpinifolia, U. angustifolia, U. elegantissima, U. nitens, U. foliacea; Field Elm, Smooth-leaved Elm): A native of North Africa, Europe and Western Asia. They are large trees with an open habit, rounded or oval head, and slender shoots which may be pendulous. The leaves are mid green to dark green above, hairy and venous beneath, and turning yellow in winter. Leaves are coarsely toothed, oval to oblanceolate, smooth and leathery. It can be used as a windbreak in coastal areas.       

U. procera (syn. U. campestris; U. minor var. vulgaris; English Elm): A large tree with downy shoots growing to 9m. The mid to dark green leaves are rounded with a rough surface, and are sharply double toothed. They seldom produce fruit, but when they do it is smooth. They do not produce seed but spread by suckers.

U. x hollandica (Dutch Elm): A natural hybrid native to Western Europe and reaches a height of 11m with leaves that are dark green, shiny and obovate. A number of variable hybrids exist. They are generally fast growing. They are not the source of Dutch elm disease as is sometimes erroneously thought. Rather, research into the disease first took place in Holland.    

 

Plant Health

Pests include caterpillars, aphids and gall mites which can result in blistered leaves. The elm bark beetle is a more serious problem; responsible for transmitting ‘Dutch elm disease’ which has decimated populations of this wonderful species in the Northern Hemisphere in recent decades. This disease causes browning of leaves which remain attached to dead branches. Whilst large infected branches may be removed, an infected tree will ultimately die. Other diseases include bracket fungi developing on dead wood, die-back and canker caused by fungi, and coral spot where reddish pink pustules develop towards the base of dead wood. Honey fungus may also kill trees quickly.   

More info

Widespread in temperate areas of the northern hemisphere; around 45 species.

 

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