5th September 2009

5th September 2009 - Tree Trail Ness Gardens

We looked at and discussed over 60 different species of trees.

Ness of course is famous for its Sorbus collection, being the largest in the country. Sorbus rosea was introduced to cultivation through Ness, it was wild sourced from Gillgit in Pakistan in the 1980’s and has whitish pink berries. Sorbus leyana, Ley`s Whitebeam is described as Britain’s rarest tree. It is an apomictic microspecies, and is thought to be derived from Rowan (S. aucuparia) and Rock Whitebeam (S. rupicola). It is endemic to south Wales and is critically endangered. Sorbus domestica, the True Service Tree is native from southern Europe to north Africa. It was disputed to be native to Britain until it was found near Cardiff in 1984. It is a big tree, with leaves like Rowan but slightly bigger and hairy beneath. It exists in two forms, one with apple-shaped fruit (f.pomifera), and one with pear-shaped fruit (f.pyrifera).

There are many lovely Birches at Ness. Betula nigra, River Birch grows on river banks and waterways in the warmer parts of eastern USA, where it can survive being wet for several weeks at a time. The seeds ripen early and fall when the water is lowest to germinate in the moist rich soil. It has dark rugged bark when young, but the mature bark is pinkish orange and shaggy. It is a lovely tree to plant in a damp area. Betula dahurica is similar to B.nigra but is even nicer, it is found in Japan and Russia. Betula michauxii, the tiny Swamp Birch was sourced from an oil refinery access road in a place called Come by Chance, Newfoundland, Canada in 1988.

We looked a several Maples. Acer platanoides ‘Crimsin King’ is a variant of Norway Maple with nice crimson fruits. Acer griseum, Paper-bark Maple was brought back from China by Ernest Wilson in 1901, and has bark with papery scrolls, and lovely autumn colour. The nutlets have a very thick shell and often form without pollination so the tree is difficult to raise from seed. Acer cappadocicum is like Norway Maple but the fruits are more angled and the leaves less lobed. It turns butter-yellow in Autumn and is one of the four species of Maple with latex. It is native to Asia Minor. Acer saccharinum, Silver Maple is native to eastern USA. It is airy and willowy, with silver under its leaves it is attractive when ruffled by wind. It can be confused with Sugar Maple, A.saccharum, the one on Canada’s flag. Silver Maple is closely related to A.rubrum and like it produces red flowers in spring before the leaves. It does produce a small amount maple syrup. Acer carpinifolium, Hornbeam-leaved Maple has leaves like hornbeam, elegant, hanging and golden in autumn.

Two species of Liquidambar were considered. Liquidambar styraciflua, American Sweet Gum, has five-lobed leaves which are star-like and has good autumn colour. Liquidambar formosana, Chinese Sweet Gum has matt leaves with usually only three lobes, but occasionally five. The fruits have curled spines.

Platanus orientalis, Oriental Plane is from south east Europe and has deeper lobes than London Plane (which is the hybrid of P.orientalis and P.occidentalis). The species we looked at is most likely ‘Digitata’, which has narrow lobes.

There are some lovely Alders at Ness. We looked at the elegant Alnus glutinosa ‘Imperialis’ a variant of Common Alder, more graceful and finely cut than ‘Laciniata’ and very Japanese-looking. We also looked at Alnus sieboldiana, a splendid tree named after Von Siebold, a German botanist who worked in Japan as a doctor in the 1820s and amassed thousands of both living and preserved specimens of plants. This tree has big leaves edged with yellow teeth and impressive cones.

The two species of Tulip Tree were compared. Liriodendron tulipifera, the Tulip Tree from eastern USA, where it is known as Yellow Poplar, has flowers like 5cm ‘tulips’ of green and orange. Liriodendron chinense, Chinese Tulip Tree, from east China to north Vietnam, has leaves which are purple in spring, more waisted and whiter underneath.

We considered the differences between Firs and Spruces. Abies procera, Noble Fir, was discovered and brought to Britain from the US in 1830 by David Douglas. It has huge cones which disintegrate on the tree and are enjoyed by squirrels. It is very successful in Britain and regenerates naturally in Scotland. Abies concolor, Colorado White Fir, grows from Utah to Mexico and has leaves which are pale and curl vertically above the shoot. A.delavayi var forrestii, also known as A. forrestii was discovered by Forrest in China in 1910. It has glossy dark green leaves and lovely purple cones. Two Spruces were compared to the Firs, Picea smithiana, Morinda Spruce and Picea spinulosa, Sikkim Spruce. The main difference between Spruces and Firs are that Spruces have ‘pegs’ on old shoots which are left when the leaves fall and they have pendulous cones. Firs don’t have pegs but the leaves leave small scars, they have resin blisters on the trunk and cones which disintegrate on the tree.

A few species of Pines were considered. Pinus longaeva, the Great Basin Bristlecone Pine is one of the worlds longest lived trees, living nearly 5000 years. It grows in parts of California, Nevada and Utah. One was found to have 4,862 annual rings when it met its tragic end in 1964, accidentally cut down by forest rangers sent to take a core sample for counting. Pinus nigra ssp. laricio, Corsican Pine, can be differentiated from Pinus nigra ssp.nigra, Austrian Pine, by having a pale trunk, longer twisted needles, cleaner straighter bole and boughs like poles. On the other hand Austrian Pine is heavy limbed and has dark bark. We looked at the splendid row of Austrian Pines planted by A K Bulley as a windbreak. Pinus contorta ssp. contorta, Shore Pine is like Lodgepole Pine (P.contorta ssp. latifolia) but has shorter twisted needles pressed closer to the shoot and is more bushy. Pinus wallichiana, Bhutan Pine is from the Himalayas and has blue green leaves in 5’s which are long enough to droop.

We compared the two deciduous conifers. Metasequoia glyptostroboides, Dawn Redwood, a critically endangered tree in the wild, discovered in 1941 in a village in China, it has leaves, buds and side shoots all opposite, it comes into leaf earlier and has spongier darker bark. Taxodium distichum, Swamp Cypress, from eastern USA, can cope with waterlogged conditions by throwing up ‘knees’ or pneumatophores, which trap silt around the roots and probably help the roots to breathe. It has side shoots borne alternately (actually helically) along twigs, comes into leaf later and has a much more feathery look.

Three Redwoods were looked at and compared. Sequoiadendron giganteum, Giant Sequoia or Wellingtonia, is the world’s largest tree, has a flared bole with soft spongy bark and scale-like leaves. It is native to California where it grows on the western slopes of the Sierra Nevada. Cryptomeria japonica, Japanese Red Cedar, a giant tree in the mountains of Japan, is a redwood with hard bark, it has awl shaped leaves arranged in a helix around the shoot and is an excellent reddish timber. Sequoia sempervirens ‘Cantab’ is a variant of Coast Redwood which originated from ‘witches brooms’ at the University Botanic Gardens at Cambridge. Massive brooms could be seen in the tree we examined.

From the terrace three species of Cedars could be easily compared. Cedrus deodora, Deodar, from the Himalayas has a drooping leader, shoots that hang and leaves which are longer and softer than the others. Cedrus libani, Cedar of Lebanon has black-brown bark and level plates of foliage. Cedrus atlatica, Atlas Cedar is most often seen as ‘glauca’, has greyer bark, shorter needles in rosettes and branch tips that ascend.

Some other notable trees were:

Aesculus wangii is found in China and Vietnam, where it is threatened by habitat loss, and bears enormous panicles (to 45cm) of scented yellow purple-brown spotted flowers in spring, followed by large encased seeds (conkers) up to 10cm across. Although the Ness specimen is the British Champion it has not flowered yet.

Salix alba var sericea, Silver Willow is a County Champion for girth and height. The leaves stay silky hairy above, so that the tree looks like a puff of pale smoke from a distance.

Fagus sylvatica ‘Asplenifolia’ Fern-leaved Beech, a ‘chimaera’ with inner tissues of typical Beech enveloped by cells of the ‘sport’, so that sprouts of normal leaves will often grow from the trunk especially after injury. Both types of leaves were visible on the tree.

Cercidiphyllum japonicum, Katsura is from China and southern Japan (where it is endangered), it has opposite leaves that flush pink and die off lemon and orange with a smell of caramel from summer on. We had to smell four different trees before all the group could smell the caramel!

Davidia involucrata var vilmoriniana, the Dove or Handkerchief Tree is fertilized by bats, and has huge white hanging bracts early in the summer. This variety, which is the one most planted as it is the most hardy, is not hairy on the under surface of the leaf in comparison with Davidia involucrata var involucrata which is very downy underneath.

Cunninghamia lanceolata, Chinese Fir, is native to China to Vietnam and its leaves clasp the shoot all round in a helix. ‘Glauca’ has metallic blue-bloomed foliage due to more vivid stomatal bands and a waxy bloom. It is more hardy than the type which is wind sensitive

Thuja plicata, Western Red Cedar, from the USA, brought here 1853, has dull white stripes under the leaves and a smell of pineapple which fills the air around the tree on warm days.

Thujopsis dolebrata, Hiba, is related to Thuja but has broader leaves ‘painted’ white underneath, which are more glossy, and scale-like resembling tiny axe-heads (botanical name 'dolabra' means hatchet). It is an important forestry tree in Japan, the wood being light, strong and hard-wearing.

Populus wilsonii, a beautiful and unusual Poplar, it has big sea-green leaves which flap noisily and turn black on falling. It was found in Yunnan in China in 1907 by Ernest Wilson.

Polylepis australis is from high altitudes in the Andes, its generic name refers to the peeling bark.

Drimys winteri, Winters Bark is native to the central Andes, it has aromatic bark once chewed by sailors to combat scurvy and so was collected by Francis Drake. The fruits have been used as a pepper substitute.

Luma apiculata, Chilean or Orange-barked Myrtle is closely related to Myrtus, it has aromatic almost black foliage, abundant white flowers, cinnamon bark which peels to white and fruits which are edible and sweet. It has become naturalised in some southern Ireland gardens.

Phymosia umbellata, Mexican Bush Mallow has deep red mallow-like flowers and green velvety leaves. Apparently hummingbirds love it.

Styrax japonicus, Snowbell Tree, from Japan, has buds like furry mittens, massed snow white flowers which droop below every branch in early summer to be replaced by fruits like dangly earrings. It is hardy yet delicate, a lovely tree to plant.

Poncirrus trifoliata, Japanese Bitter Orange is closely related to Citrus and has white flowers, yellow inedible fruits, trifoliate leaves and spines. It is from China and Korea and makes an attractive thorny hedge which is hardy.

Juglans nigra, Black Walnut is native to eastern and central USA. The leaves have 10-23 slender leaflets often with no end one, and are finely toothed and downy underneath. This specimen is the County Champion for girth and height and was laden with fruit.

Ailanthus altissima, the Tree of Heaven is native to northern China but naturalises in US cities and Southern Europe as it survives in dry polluted urban sites. Male trees are reputed to smell bad. It has extra-floral nectaries like Prunus.

Phellodendron amurense, Amur Cork Tree resembles Ailanthus but the fruit is a drupe and the winter buds are enclosed.

Pterocarya x rhederiana, the hybrid of P.fraxinifolia (Caucasian Wingnut) and P.stenoptera (Chinese Wingnut), is a big tree with long hanging fruits, and a County Champion.

We compared the cut stumps of a Beech and a Giant Redwood to see different thickness of the bark and the annual rings. We listened to water moving up Eucalyptus Trees.

And also, we visited the Quercus robur planted in memory of Vera Gordon and were very pleased to see it looking healthy enough to support four types of gall! (Marble, Spangle, Silk-button and Artichoke).

Maria Knowles