Thorp Perrow Arboretum

Geoff Appleyard Memorial Tree Walk

Friday 15th September 2023

Leader: Graham Heffernan

Number of attendees: 16

Graham had visited the site not too long before our outing and worked out a route on which he wanted to take us. With more than 4,300 species listed on the Arboretum’s catalogue Graham had selected a small selection. Even so I noted 60 trees on the day, and I may have missed a few.

Graham introduced the walk by giving us a potted history of the site. The site originated in the 16th and 17th centuries with parkland trees. The Arboretum proper was created by Colonel Sir Leonard Ropner (1895–1977) in 1931. This gentleman also founded several gardens in the park. Today the Thorp Perrow estate is one of the finest arboreta in the United Kingdom. It holds five National Plant Collections: Tilia (Lime), Fraxinus (Ash), Cotinus (Smoke Bush), Laburnum and Juglans (Walnut), and has 48 Champion Trees in its collection.

The following are notes about some of the trees we saw, including some of Graham’s interesting information and ID tips. In most cases I have also put the Arboretum Tree number, in case anyone wants to re-visit in the future.

Not too far from the entrance was our first tree, a Cornus mas (Cornelian Cherry). Despite its common name this is a Dogwood, though it was the right time of the year to be sporting some very Cherry like berries. The pattern of the leaf veins points to its species. Z210.

Another Dogwood was not too far away, this time Cornus controversa ‘Variegata’ (Table Dogwood). This tree is sometimes referred to as ‘The Wedding Cake Tree’ due to the tiered nature of its branching. This cultivar has cream edging to its leaves. Z277.

As we walked Graham pointed out some yellowish Lawson’s Cypress’s. These are ‘Aura’ types of Chamaecyparis lawsoniana. There are a lot of these with different cultivar names. The cones have small spines on the scales, there is a very clear resin gland on the tips of the leaves, and a seam where the two sides of the leaves meet. Later we saw a C. lawsoniana 'Imbricata Pendula' X391 – this is hugely changed from the species, a spire with very pendulous branches. The leaves are acute but sharp, the resin glands indistinct. Graham asked whether we liked it as a specimen tree, the general opinion was unfavourable.

We met other Cypresses to compare the Lawson’s with; Chamaecyparis obtusa (Hinoki Cypress) X22, the cones are like Lawson's but without the spine on the cone scales. Chamaecyparis pisifera (Sawara Cypress) X016, have very small cones, with indistinct resin glands. Cupressa arizonica (Arizona Cypress) X002, 3D sprays, larger cones, the yellow ends of the leaves are pollen showing through.

The Gingko biloba (this one had large leaves) was known from fossil records before a live specimen was found. In 195 million years it has hardly changed, though many of the tree's defence features were developed against predators that no longer exist. It has succulent fruit. The leaves cover the branches well. It is not a flowering plant, more a coniferous type seed with no protection, and no ovary. You see male planted trees usually, as female flowers make a mess and smell when they fall. Z363.

Prunus x yedoensis 'Shidare Yoshino' X148 (Yoshino Cherry). This lovely Cherry is not known to grow anywhere in the wild and is thought to be a hybrid between Prunus speciosa (Oshima Cherry) which we also saw, X142 (veteran tree), and Prunus subhirtella. When looking at the Oshima Cherry Graham described how Cherry bark breaks down as it ages. It begins with nice shining bark and horizontal rows of lenticels; these eventually break up and this results in very craggy bark on older trees.

We stopped for lunch by the monument at the south end of the site. This is overlooked by an arc of small Taxus baccata 'Fastigiata' (Irish Yew). Here Graham explained how Yews have arils, not berries. This soft red covering is open at one end, the poisonous seed inside is naked, and has no ovary as with other conifers. The aril is the only part of the Yew tree that isn’t poisonous, though all our group declined to try one!

After lunch we visited a few pines of different species comparing, the leaves and cone sizes.

• Pinus pinea (Stone Pine) T12, sometimes known as the Umbrella Pine due to the way it grows in its native range in the Mediterranean.

• Pinus armandii (Chinese White Pine) V330, long needles in fascicles of 5 and smooth bark (not what you would think of as Pine bark).

• Pinus bungeana (Lacebark Pine) V329, with bark unique among pines, reminiscent of London Plane.

• Pinus gregii (Gregg Pine) V227, a tree restricted in its native range to cold upland areas in northern Mexico.

• Pinus muricata (Bishop's Pine) V197, the cones face backwards in clusters on the branches, sometimes growing out of the trunk! The cones remain unopened for many years until fire causes them to open and release the seeds.

• Pinus coulteri (Big Cone Pine) V212, believed to produce the world's largest cones when grown in their native area.

• Pinus nigra subsp. pallasiana (Turkish Black Pine) V124, listed as uncommon in the catalogue.

Malus sylvestris (Wild Crab Apple) is one of our native trees, but now quite rare in the wild. V192 is a good example and was fruiting abundantly. Tart apple pie anyone? For comparison, soon after we looked at a Champion Tree, Malus kansuensis (Calva Crab Apple) also in fruit, small red oval apples. Another, unusual and uncommon apple is the Malus tribolata (Lebanese Wild Apple) V121. The leaves as the scientific name suggests are 3-lobed.

Viburnum rhytidophyllum (Leatherleaf Viburnum) V001 is interesting. Underneath the leaves the hairs are star shaped, and the upper surface is very leathery, hence the common name.

Halesia carolina (Snowbell Tree / Carolina Silverbell) V21. The snowbell name comes from the spring flowers. At this time of year, we looked at the fruits which have 4 deep wings.

A tall tree, with a narrow profile, being allowed space for one to step back and few from a distance is the Calocedrus decurrens (Incense Cedar) U26/U30. Graham mentioned that this tree has soft, straight wood, non-splintering wood which is suitable for pencil manufacture.

We compared several Acer species with different characteristics:

• Acer cappadocium (Cappadocian Maple) V0097, has leaves which are not serrated between its 5 lobes and goes butter yellow in Autumn, we were too early!

• Acer platanoides (Norway Maple) O102, has large leaves with 5 lobes, but with some points on each lobe. Graham mentioned the spaces between the spines on the leaves are concave, whereas in in Acer pseudoplatanus (Sycamore) they are convex.

• Acer maximowiczianum (Nikko Maple) O017, is one of several maples to have trifoliate leaves.

• Acer capillipes (Red Snake-bark Maple) N129, the tree has light red, brown, and green bark supposedly reminiscent of snake’s skin.

Eucryphia x intermedia (Brush bush) N104. This tree has quite large flowers, and luckily for us the tree was in flower on our visit.

Juglans cinerea (Butternut) M076. This is a Walnut species, we did a test on a Walnut twig to show that the species has chambered pith in the twigs, other species with similar leaf arrangements do not have this.

Near the end of the walk were 2 exceptional trees, first Pterocarya fraxinifolia (Caucasian Wingnut) which was making a great display of the fruits which gives the common name to the tree. The long strings of semi-circular wings on the nuts.

Almost certainly the oldest tree is Catherine Parr’s Oak; Quercus robur (Pendunculate Oak). This is said to have been planted by her, and this is very possible though not proven. If true the tree would be around 400 years old, and this is backed up by its girth which is about right for a tree of that age.

Many thanks to Graham doing the research, sharing his knowledge and experience, and to Bruce for recording all the species. The group had a very pleasant and interesting day.

Text and photographs by Ian D