As I walked around the garden today here at RBGE, there was a real sense of autumn in the air. Golden leaves lay scattered on the ground, the smell of cold dampness filled my nostrils and there was enough of a chill to need a warm cosy jacket.
Whilst enjoying the sights and smells of autumn I took some aerial drone photographs of trees in our Living Collection that have magnificent autumn colour. This gives a new perspective to viewing their incredible beauty and structure.
Liriodendron tulipifera
Liriodendron tulipifera is a tall, stately, deciduous tree with a pyramidal to broad conical habit. The attractive foliage is bright green and slightly glossy, turning golden yellow in the autumn.
The American Tulip Tree as it is commonly known is a popular plant for gardens. The leaves flutter on their long stalks as if to draw attention to their special shape, and the American name ‘Tulip Poplar’ reminds us of this, and of the trees timber qualities and rapid growth in the deep moist soils which it prefers. On poor dry or chalky soils it will survive rather than flourish. In Europe, it grows as far north as Finland. However, in southern England only a few, younger specimens show the long, straight characteristic of the tree thriving in its native forests in the USA. I remember the magnificent trees of 50 m tall growing in the native woodland area at Longwood Gardens in Pennsylvania whilst I worked there in 2015-2016.
This beautiful tree requires a moist fertile soil, preferably slightly acidic, it will thrive in deep loam that will not dry out. Plant in full sun or part shade.
Metasequoia glyptostroboides
A large tree of conical habit. Soft attractive flaky cinnamon bark. Bright apple green leaves during summer becoming tawny pink and golden orange in autumn. Small green cones turn brown when ripe. One of the most rewarding of trees to plant for the future. First observed by a Chinese botanist in 1941, despite knowledge of its existence in pre-historic times from fossil records. Seeds were collected in 1947 and sent to the Arnold Arboretum. They were then sent to other gardens in America and Europe in 1948. This tree was awarded the Royal Horticultural Society’s Award of Garden Merit and will grow quickly. It thrives in moist but well-drained soil in a sheltered position with sun or partial shade. It is also very tolerant of air pollution and waterlogged soils.
Liquidambar acalycina
This tree was collected and introduced to N. American cultivation by the Sino-American Botanical Expedition to China in 1980 (SABE 1950). The first opportunity for many decades for American botanists to explore and collect seed from the vast array of native Chinese plants. Roy Lancaster subsequently introduced seed from one of the original trees growing at The Arnold Arboretum. It is from this tree at Westonbirt Arboretum that two trees were propagated and grown on at the Royal Botanic Garden Edinburgh in 2015. They are planted in the vicinity of the Caledonian Hall, where they have grown well and now are showing incredible autumn colour starting yellow and turning to a rich purple. Liquidambar should be planted in full sun to achieve their best colour, in neutral to acid soil that is moist but well-drained. Once the trees mature, they tolerate occasional drought as well as periodic flooding. Protect from frost when young.
Taxodium distichum
The colour of this tree in Autumn is incredible. This tree is one of the most beautiful and interesting that can be grown in wet places, but can also thrive in ordinary soil. Native to the United States of America from S. Delaware to Florida, west to Texas, and extending northwards in the Mississippi valley. The ‘knees’ produced by the roots of the tree are often known as pneumatophores – a term coined at a time when it was believed that they serve to supply air to the roots when these are immersed in water. But research carried out in the United States has shown that their removal makes no difference to the health of the tree. In cultivation they tend to be produced by trees growing beside still or running water, and then not always. The foliage is feathery and delicate. The most tender green in spring, and dying off a rich fiery brown in autumn. It is fully hardy, and grows well in Scotland, despite the coolness of our summers.
Quercus robur
The broad, dome-headed tree is the more common of the two native oaks, the other being Quercus petraea. The lobed leaves are dark green above, paler underneath, turning a deep orange in autumn. Known as one of the longest-lived and most valuable timber trees of the world and is still frequently used in house-building – floors and panelling. Grow in deep, fertile, well-drained soil. The tree is adaptable to most soils even heavy clay.
National Tree Week is the UK’s largest annual tree celebration, running from Saturday 27 November to Sunday 5 December. Across the country, people will be planting thousands of trees to mark the start of the winter tree planting season. Trees and hedgerows are some of the most powerful tools we have in the fight against climate change.