Head Gardener's Blog: Deciduous Evergreens
The Ginkgo, standing on the parkland as you come into Riverhill..
Indulge me and let me take you back to October 2006. I had very luckily started a gardening apprenticeship with the National Trust and was thrilled to be at the beginning of my gardening career. I had been in the job less than 8 weeks, was young, naive and had a lot to learn (and was well aware of it) however I was fairly certain I knew the difference between a deciduous and evergreen tree. It's simple isn't it? Deciduous trees lose their leaves in winter and evergreens/conifers keep their needles all year…. Wrong!
Well not totally wrong, in the whole of course that is the case. However, the deputy head gardener at Scotney Castle took great glee in enlightening me on a group of plants known as the 'deciduous conifers'. I know an oxymoron! It certainly had me flummoxed.
Worldwide there are about 20 species of trees that are considered to be deciduous conifers, not all of them will grow in our climate. The ones that do are split into four genera: Larix, Taxodium, Metasequoia and Ginkgo. The large majority of deciduous conifers belong to the genus of Larix (Larch). The most common by far in the gardens of this country is the European Larch, Larix decidua (decidua, the clue is even in the name)
The only larch of any size is on the drive at Riverhill. It's not a particularly beautiful specimen due to the fact it got battered in the 1987 storm but all the same it has survived to this day and is one of the deciduous evergreens.
The second deciduous conifer to be found at Riverhill is the swamp cypress (Taxodium distichum). In fact we have two and they are found at the bottom of the orchard sweep. And this time of year their fine needles turn a fantastic coppery red. Taxodium distichum originates from the swamps of the southeast USA and have adapted to these conditions. The roots of Taxodium have the ability to grow adaptations, known as knees, that protrude above the surface and allow the tree to take in oxygen.
The Taxodium at the bottom of the Orchard Sweep.
The Larch that stands at the entrance to Riverhill.
Metasequoia (with Larch in the background) On the driveway at Riverhill.
The third is Metasequoia glyptostroboides (I know a mouthful!), otherwise known as dawn redwood. This is a tree with a quite fascinating history. It was once thought that this tree had gone the same way as the Dodo, fossils had been found but no living specimen had. Until 1941 when it was discovered growing in central China. Its discovery sent shock waves through the botanical fraternity and there was a mad rush for enthusiasts and landowners to get their hands on this new plant.
There are now several Metasequoias at Riverhill but the one in the wood garden has its own tale to tell. Soon after its discovery in 1941 seed was collected and sent around the world. Some of which was sent to Arnold Arboretum in Boston where they were germinated and grown on. Subsequently in 1948 Arnold Arboretum showed the saplings at the Garden Show at Olympic, which the then owners of Riverhill Major David and Evelyn Rogers, attended. When David and Evelyn enquired about buying one they were told firmly that they were for display only and far too precious to sell. However at the end of the afternoon, when all the plants were being packed away one would not fit back in the box and so it was given to Evelyn, who of course was thrilled. Unfortunately, they were on their way to the theatre and so had little choice but to take the plant with them. So, we may not have had the first Metasequoia to be planted in England but we are fairly certain that we had the first (and probably only) one go to the theatre.
The last deciduous conifer to be found at Riverhill is the Ginkgo biloba (Maidenhair tree). Now in truth the Ginkgo has been reclassified in the last few years and is now not considered to be a conifer. In fact it has been classified into their own division, Ginkgophyta, with a single class, order, family, genus and species, of which Ginkgo biloba is the only extant representative.
However for the purposes of this I have included it as it has many traits of a conifer. The fan shaped leaves are actually as a result of its needles fusing together. Also Ginkgo like all other conifers produces a 'naked seed' (gymnosperm), meaning their seeds are not enclosed in a ripened fruit but are protected by cones or by a fleshy seed coat.
Ginko leaf.
The Ginkgo is known as the "living fossil plant", as it is the oldest species of tree growing on Earth right now. Fossils of the maidenhair tree dating back to the Jurassic period, 200 million years ago, have been found in Asia, Europe and North America. In fact Ginkgo trees are known for their unique ability to survive as they will tolerate poor soils and will withstand poisonous smog and acid rain. The best proof if it's ability to survive are the Ginkgo trees that continue to grow in Hiroshima and Nagasaki. These trees, some of which were within 2km of the blast centre, would have been subjected to huge amounts of radiation and it is thought no living organism would survive. In the autumn of 1945 they looked like match sticks protruding from the ground, their leaves incinerated, branches ripped off and their bark completely scorched. Yet by the next spring they were coming into leaf and have done every spring since.
Happy leaf raking!