Instead of being surrounded by the local flora of the region we found ourselves surrounded by exotic species of the world! Our venue last Thursday, Durham University Botanic Garden. Mike Hughes from the Botanic Garden was our guide.
The Botanic Garden has come a long way since moving to this site in 1970. In the former days wildflowers and natural habitats were deemed messy and weren’t valued as much as they should have been, lawns were kept pristine and pesticides were used to destroy any weeds that dared to appear. How things have changed!
Our first stop was the cornfield annuals border. Cornfield annuals such as corncockle (Agrostemma githago), poppy (Papaver rhoeas), cornflower (Centaurea cyanus) and marigold (Glebionis segetum) were once common features of traditional farming areas but have now have largely disappeared due to changes in agricultural methods. Cornfield annuals can only exist where soil is disturbed, which is why they used to grow in ploughed fields.
Although there may not be much to look in the winter, the borders are a riot of colour in the summer. Conditions of cornfields have been replicated by clearing and cultivating the ground to create a seedbed. After several years of cornfield annuals, the borders at the Botanic Garden have a good seed bank and need no additional seed.
Former dolomite paths around the gardens attracted weeds and consequently were sprayed with gallons of pesticide. Paths have now been replaced with paving and tarmac and the university no longer uses pesticides in the gardens.
Conservation and biodiversity are now key factors in the maintenance of the Botanic Garden and wildlife is actively encouraged.
Hazel trees are coppiced on a seven year rotation. New shoots growing from the stumps create different levels of shade and vegetation densities and a wide variety of habitat niches. In the past, coppicing was traditionally used to produce a variety of building materials (hurdles, wattle and daub etc.) and charcoal.
‘Messy’ areas are now allowed, seed heads are left over winter for the birds and the dead leaves left as a mulch for the plants.
Mike showed us a lot of interesting plants and trees! The corkscrew hazel (Corylus avellana ‘Contorta’) with its twisted stems, a 150 year old monkey puzzle tree (Araucaria araucana) and a walnut tree (Juglans sp) with its key identifiable striations seen inside the branches.
There was a splash of colour from the camellias and a shrub that smelt of chocolate!
We met these characters asleep in a trailer awaiting their retirement home!
We then proceeded to explore the woodland at the bottom of the gardens. Mike pointed out some conservation work in the woods in the form of coronet cuts on dead and dying tree limbs. The aim here being to mimic the natural breakage of limbs instead of removal by simply sawing off just above the branch collar. It is believed that this method is better for the trees and the rough cuts leave pockets or niches for fungi and invertebrates to colonise, creating more dead wood habitat. At the same time the pruning makes the limb safer.
We were welcomed to the meadows by a flock of Hebridean and Manx Loaghtan sheep. These hardy sheep graze and preserve both the meadows and arboretum pasture encouraging wildlife. Without grazing, or some other kind of management, these habitats would revert to scrub and woodland and their biodiversity would be lost.
The surrounding area uncovered a range of habitats including bluebell woods, woodland glades (with spring and summer orchids) and meadows. The diversity of the meadows has been increased using ‘green hay’ which is where cuttings are taken from ‘donor’ sites rich in flower species and transferred to nearby ‘receptor’ sites where species diversity is poorer. The area is also used by the Archaeological department for research into carbon capture.
We came across signs of the area’s mining past, hidden tunnels and disused railway tracks. And some red-berried elderberry (Sambucus racemosa) another curios relic from a past time.
It was a fascinating morning. Thanks to Mike Hughes from the Botanic Garden for showing us around and making it such an interesting day.
Thanks to Steve for arranging the event and to Jeff for supplying a lot of the photos (the better ones).