The educational prowess of Durham University may be well known, but perhaps less heralded are the benefits of a visit to its botanical gardens, which have many wonderful trees and plenty of information to impart. 

WHILE the Durham University Botanical Gardens has only been located on its current site since 1969, there has been a University Botanical Garden in Durham since 1925. It was set up back then as an experimental garden, an objective which continues to the present day, being used a teaching and research location for students. It also provides a venue for educational visits and a wonderful 25-acre site for the public to enjoy.

It is not hard to see why it has won many awards, as it has something to offer everyone. Although I visited in early January, it is easy to see, with the plants and trees that grow there, that it would offer many different colour palettes and vistas during the year. There are certainly mature woodlands and wildflower meadows to consider, but also a North American Arboretum, bamboo groves and glasshouses full of both exotic plants and insects. All of this just on the outskirts of Durham city centre.

Forestry Journal: Beech tree stump and logs left in place after being diseased and brought down to create biodiversity in the areaBeech tree stump and logs left in place after being diseased and brought down to create biodiversity in the area (Image: eA/JH)

The visitor centre, opened by Dame Margot Fonteyn when she was chancellor of the university in 1988, is small but adequate with a café, some displays and maps. Walking outside, you are afforded a great view of what lays before you from this raised position. The map numbers all of the points of interest in the gardens so I decided to follow it sequentially to ensure I got to see all it had to offer, starting with the glasshouses, passing the Prince Bishop’s Garden and an interesting collection of grasses on the way.

The glasshouses consist of a Cactus House, with a wide range of cacti and succulent plants, while the Tropical House is used to replicate the humid environment of a rainforest complete with rain (or at least a misty spray of water). In the Tropical House are banana and coffee trees, as well as giant bamboo and orchids. Exiting the glasshouses, there are a number of parts of the garden that are given over to collections from Southern Hemisphere countries and the first glimpse of the Millennium Bug, a galvanised metal artwork.

The striking Millennium Bug, created by a local artist, took eight months to create and has become popular with visitors, especially children, in the last two decades that it has been present at the garden. Perhaps of less interest to many visitors, but equally as fascinating, is the stump of what was a specimen oak tree.

An attached notice says the oak suffered major limb damage during gales back in 2018. It goes on to say that the tree had a ‘weak union in one of its crotches’, which split due to the winds and was left hanging in the canopy. This left it as a danger to the public, along with the fact that the two main trunks were also showing signs of weak unions and had ‘weeping wounds’. The oak was in effect unbalanced and would in all likelihood have been bought down in a future storm.

Forestry Journal: Oak tree trunk left in place after being taken down due to major limb damage but left to become a ‘tall pollarded monolith’ and a home to ‘invertebrates’Oak tree trunk left in place after being taken down due to major limb damage but left to become a ‘tall pollarded monolith’ and a home to ‘invertebrates’ (Image: eA/JH)

Left with a dangerous and effectively ruined oak, those responsible for its care took the decision to bring it down. The process to remove the dangerous limbs ended up leaving what is described as a ‘tall, pollarded monolith’ that in time may regenerate.

Perhaps it is fitting that close by there is a new tree planting, part of the Queen’s Green Canopy to celebrate the late Queen’s Platinum Jubilee in 2022. Walking on down the hill past the ‘Conifer Lawn’, with a lovely array of various conifers, takes us past the research beds and a number of small information plaques. One I noted explained about the willow (Salix) tree. It described how wood from it is used in the making of cricket bats, telling you how and where it grows and explaining that there are of 300 species of willow growing in the world. A Peking willow (Salix matsudana) grows nearby.

Further on and the education for visitors continues at a grove of dawn redwoods (Metasequoia glyptostroboides), where another plaque, part of the botanic garden science trail, explains about these trees only being known as fossils and thought to have been extinct, before some were discovered growing in China in 1944. The use of trees to illustrate scientific points continues with a Foxglove tree (Paulownia tomentosa), which highlights the impact of climate change.

The plaque next to the tree informs visitors that Durham is at the northernmost limits of where this tree species can survive. It goes on to say that for the first decade of its existence at the botanical gardens it struggled to do so. However, because of the change in climate in this area to milder and wetter winters, the tree started to do better. In fact, it visibly improve, actually flowering for the first time in 2011. As climate change continues, more ‘exotic species’ will be able to be grown in the UK.

Forestry Journal: The Sakura Friendship Garden.The Sakura Friendship Garden. (Image: eA/JH)

There is a lovely collection of trees native to Japan and a Foxglove sculpture to admire on the way towards the Sakura Friendship Garden. The sculpture is a series of numbers on a wooden post, designed by the artist to make people stop and wonder. Looking closer you realise the ‘abstract’ numbers imitate the organic structure of the bells of a foxglove plant. The numbers form a link with each other, shaped like the bells in the bloom of the plant. Each has its own shape but is linked to the others, in much the same way that flowers need to follow the rules of the season. One thing is for sure, the sculpture certainly stands out.

The Sakura Friendship Garden is formed of a circle of small stone benches surrounded by Japanese flowering cherry trees. Unfortunately, January was not the best time to see them. When these trees are in full blossom this garden must be a lovely place in which to spend some time. Further on, next to the entrance to the University Woodland and Wildflower Meadow is yet another distinctive sculpture to admire. This series of giant fungi and was produced by Graeme Hopper, who also created the Millennium Bug artwork.

Nearby is another large trunk, the remains of a veteran beech tree which was deemed high risk. A notice explains the fungus giant polypote (Meripilus giganteus) was found in the roots, effectively making them rotten and the tree unstable. Removal was the only option, but with an eye to helping the biodiversity of the surrounding area. By ‘fracture pruning’ the beech trunk was left as a natural feature in the landscape.

The path towards the North American Arboretum passes through a bamboo grove, with a wildflower meadow and a new pinetum planted in 2010 on one side before reaching an area called the Himalayan Dell. There are some wonderful examples of common hornbeam (Carpinus betulinus) trees and some stunning looking Himalayan birch (Betula Utilis Var jacquemontii) with wonderful smooth white bark, making them noticeable from quite a distance.

The first tree of note in the North American Arboretum is a Californian redwood (Sequoia semperviren) quickly followed by an example of a tree common to this part of the world, a Sitka spruce (Picea sitchensis) and then a shore pine (Pinus contorta).

Forestry Journal: Himalayan birch (Betula utilis var jacquemontii)Himalayan birch (Betula utilis var jacquemontii) (Image: eA/JH)

As I walked around this part of the garden, it was interesting to see so many different types of tree species all native to Northern America. I liked a few in particular, such as a nice red maple (acer rubrum). Nearby grows a sweet birch (Betula jenta) whose label tells visitor that this tree species through its catkins feeds wildlife and its timber is used for joinery, veneer and paper pulp.

I must confess to being quite taken by the name of the next tree, an example of a Shagbark hickory (carya ovate). It has a shaggy, flaky bark when mature and is used to make tool handles and baseball bats. It is also, perhaps not surprisingly given its name, is used in smoke houses.

This arboretum also has growing in it an Eastern or Northern pine, which we are informed is the largest conifer of the eastern US and Canada, growing to heights of well over 30 m, and known as Weymouth pine in the UK.

There are two trees worth noting towards the exit. The first is an example of an Oregon maple or big leaf maple (Acer Macrophyllum), a tree species native to the Pacific coastal regions of Canada and North America, capable of growing to over 30 m. The timber from these trees is used for fuel and furniture making, especially piano frames. The other tree with a distinctive reddish lower trunk is a white ash (Fraxinus Americana), quite a nice tree to end on in this part of the gardens.

In the Woodland Garden, an information board next to a wonderful looking corkscrew hazel (Corylus avellana contorta) explains about natural mutants. This tree species is a natural mutant of wild hazel, the mutation taking the form of contorted shoots and distorted leaves. The original example of this species was found growing in Gloucestershire in 1870. Because it is not propagated from seed but rather by cuttings, all the trees of this species growing today in the UK are clones of the original tree from Gloucestershire.

Forestry Journal: Millennium Bug artwork – created two decades ago and a popular garden attraction.Millennium Bug artwork – created two decades ago and a popular garden attraction. (Image: eA/JH)

Pride of place in the Chillan collection used to be a tall monkey puzzle (Araucaria araucana). Sadly now it is just a small stump as the tree was cut down. Although it reached 160 years old in 2020, as can be quite common with this type of tree, it suddenly began to deteriorate and was felled, with just the stump, somewhat like an elephant’s foot, being left in place.

Before heading back to the visitor centre I was drawn to the central area of the gardens, surrounded by number of trees native to the UK, and to check out the woodland trail. Trail trees include oak, beech, and smaller numbers of sycamorem birch and rowan. A veteran beech boasts another information plaque explaining how trees like it draw lots of water through their roots, and, as in this tree's case, having a surface area of around 675 m2 releases water vapour into the atmosphere to fall as rain elsewhere. Such tidbits of information are well placed throughout the gardens.

There is time, walking back up to the visitor centre buildings, to learn about hazel coppicing for charcoal and admire a lovely example of a Norway maple (Acer platanoides) planted to commemorate a retirement. In addition, there is a rare Balkan maple (Acer hyrcanum ssp cordissectum) growing in a border which flowers with cornfield annuals. The Balkan maple was grown from a seed supplied by the University Botanic Garden Vienna and planted in 1972.

There is also a Malus hupehensis from Hupei Provence in China and a sorbus minima, a tree species that only grows in Britain. Both these trees are endangered species. The final information plaque I read explained the role of the University of Durham Botanical Garden and others like it throughout the world was to grow and distribute seeds and even saplings of such endangered species to stop them being lost to the world.