Trees Gallery - The Yorkshire Arboretum -page 11

Quercus rubra

Red oak

A deciduous tree native to N America and S Canada. It can grow 30 to 40m, with a trunk up to 2m in diameter, quite straight and not too spreading in habit. The acorns take two years to develop on the tree. It is considered invasive in Europe, and is a neophyte a plant not native to a region, introduced and escaped into the wild in recent history (after 1500). in Britain.

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Rhamnus cathartica

Buckthorn

Sometimes called purging buckthorn on account of the laxative effects its berries induce when eaten. A small, spiny tree native to England and Wales and throughout Europe. Mature trees can grow to a height of 10m, with grey-brown bark and spiny branches. The leaf buds are conical and black-brown in colour, and form on long stalks. Female flowers develop into purple-black berries ( drupes a fleshy fruit with thin skin and a central stone containing the seed), 6–10mm in diameter. The seeds within the fruit are dispersed by birds. [Woodland Trust]

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Rhododendron ciliatum

Rhododendron ciliatum

A native of the Sikkim Himalayas, one of the Hooker collections in 1848. It forms a mounding, compact shrub, slowly growing to 1.2m. It has peeling, smooth, and reddish-brown bark. The deep green evergreen foliage is elliptical, bordered with ciliate describing a structure, such as a leaf margin, fringed with fine hairs hairs. White to white flushed pink flowers are not fragrant. This species has been used quite often in hybridizing and is the parent of many widely grown and well-known hybrids.

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Rhododendron floribundum

Rhododendron floribundum

An evergreen shrub native to Szechwan, growing up to 2m in the wild. It has a stiff erect habit when young, with branchlets clothed in grey down. The leaves are a stiff, hard leathery texture, elliptical, tapered at both ends, margins recurved, a dark dull green, much wrinkled above, clothed beneath with a dull white felt. Discovered by the French missionary Pere David near Mupin in 1869.

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Rhododendron 'Hana-asobe'

Azalea hana-asobe

A Japanese evergreen, dense shrub, with strong single purplish-pink flowers that obscure the foliage. The branches are carried in layers. Best in an open situation.:

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Rhododendron niveum

Rhododendron niveum

Native to the E Himalayas, an evergreen shrub or small tree that grows to 6m, with elliptical leathery leaves, 11cm long. When young the leaves are covered in a white indumentum a covering of fine hairs , which falls off the upper surface but remains on the underside. Discovered by J. D. Hooker in Sikkim in 1849.

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Rhododendron thomsonii

Thomson's rhododendron

An evergreen shrub or small tree, to 3m high in cultivation, 6m in its native Himalayas. The bark is smooth, reddish and peeling, leaves are rounded to oval, matt dark green, with a bluish tint when young. It produces loose clusters of 3-10 bell-shaped, rich crimson flowers in mid to late spring. Discovered by J. D. Hooker in 1850 from Sikkim, where it grows at 3000-4000m.

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Salix acutifolia

Sharp leaved willow

Also known as Siberian violet-willow, long-leaved violet willow, it is native to Russia and E Asia. It is a spreading, deciduous, dioecious having male and female reproductive parts on separate plants shrub or tree, growing to 10m tall. The young shoots are deep purple with a white bloom. Male catkins are 5cm and silvery, with gold anthers, while female catkins are green and 3cm long.

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Salix x sepulcralis erythroflexuosa

Curly golden willow

A small tree or large shrub, to 5m tall, with narrow, twisted pale green leaves and yellow catkins in spring. Its pendulous, orange-yellow juvenile shoots are twisted and contorted and mature to a dark brown colour. It is often pruned or pollarded to maintain its ornamental size, and has beautiful orange-yellow bark. The leaves are usually sage green on the top and paler on the underside, pointed at each end, and growing alternately along the twigs. In early spring they bear tiny flowers and catkins. A cross between S. x sepulcralis 'Chrysocoma' x S. babylonica 'Tor'

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Salix 'Snake'

Snake willow

A twisted willow cultivar, a cross between S. alba var. argentea x S matsudana 'Tortuosa'. This could be the same as s. Dart's Snake, but I am not sure.

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Skimmia japonica

Japanese Skimmia

A rounded evergreen shrub native to Japan, China, and Southeast Asia, growing to 6m tall and wide. It has glossy, leathery leaves, cream-yellow or white fragrant flowers, followed on female plants by small, round, red fruits. Male flowerheads are large and conspicuous compared with the smaller females. The Arboretum has a group of skimmias on the west side of the lake, with cultivars 'Chilan choice', 'Kew Green', 'Obsbowli' and 'Rubella' all present. I am not sure which is pictured here.

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Sorbus aucuparia

Rowan

A native of Britain, also Europe and N Asia. Also called the mountain ash due to its pinnate leaves, though it is not related. The creamy white, 5 petalled flowers are hermaphrodite containing both male and female floral organs: pistils and stamens , developing into clusters of scarlet berries. It was planted near houses to ward off evil spirits.