Flowering insects

Why do people get so excited about orchids? They will point out a wild orchid whilst ignoring a larger and more colourful flower growing nearby. Orchids are not unusual - they form the largest group of flowering plants, with over 25,000 species. They can be locally rare, but of the 50 rarest plants in the UK only three are orchids. There must be something else which enthralls us.

Once, the earth was covered with plants only of shades of green, brown and orange, with simple flowers - like 1970s wallpaper. Then came a psychedelic revolution. Insects began searching for protein-rich pollen for food and carried it from flower to flower on their bodies, increasing pollination which before had relied on the wind. The most successful flowers were those which attracted most insects and maximised pollen uptake - resulting in the evolution of bright colours, scents, and intricate shapes and patterns. This is where the orchids excelled - they became the extreme essence of flowers and advertised the promise of sweet nectar or sex. However, orchids can be great deceivers, and they may not provide food or sex to thank the insects for their efforts. I think orchids draw us in because they exude something familiar beyond beauty - an abstraction of the animals that move through our lives. It is as if they could move without the wind.

In our first Spring in the house, at the end of March, we noticed an orchid on the front lawn: a Green-winged Orchid (Anacamptis morio). We were very excited, and thought of ways we could protect it. But as March turned to April more and more appeared in the garden, until there were hundreds around the house - particularly in the small hay meadow (where in future they will grow between the rows of fruit trees). By flowering early, they are one of the few flowers available for emerging queen bumblebees to visit and pollinate - but they deceive them and do not provide nectar.

As April progressed, patches of Tongue Orchids (Serapias lingua), a Mediterranean species, appeared in front of the hill meadow and among the trees by the small hay meadow. They are pollinated by a small black bee, Ceratina cucurbitina, which they sexually decieve by producing chemicals similar to its mating pheromones.

At the edge of the large hay meadow, a small group of Burnt Orchids (Neotinea ustulata). They attract Tachinid flies for pollination with a scent like honey, but again deceive them by not providing nectar.

Tucked away in the trees by the small hay meadow, a woodland orchid - Narrow-leaved Helliborine (Cephalanthera longifolia). It is pollinated by deceiving solitary bees such as Halictus and Lasioglossum for food.

April turned to May and, in the oak wood, a single Greater Butterfly-orchid (Platanthera chlorantha). This orchid does produce nectar, but it is found at the bottom of a 30mm long tube, and it produces a vanilla scent, but at night. Both of these facts have lead to the assumption that the orchid is pollinated by insects with a long proboscises, at night - moths.

I did not need to search for Pyramidal Orchids (Anacampus pyramidalis) as they were growing in the gravel under a tree in the courtyard. They are also pollinated by lepidoptera, which they provide with nectar.

Then appeared some orchids which take sexual deception to incredible extremes - the Bee Orchids (Ophrys). They are mostly Mediterranean and, despite looking totally unique in their complexity, there are around 200 species - making them the largest group of orchids. The flowers mimic the form and sex pheromones of female bees, and male bees will pollinate the flowers whilst trying to copulate with them. Each species mimics a different specific pollinator. The bees do become wise to this trick, and only around ten percent of flowers are pollinised each year - but each flower will produce thousands of seeds.

On our front lawn grow a number of common Bee Orchids (Ophrys apifera). They attract the solitary bee Eucera longicornis.

Take a closer look. It really is a little furry lady bee.

On a bank at the edge of the small hay meadow a bunch of Early Spider-orchids (Ophrys sphegodes). It's pattern is very variable over Europe, and 16 sub-species have been described. It is not pollinated by spiders though, but by the miner bee Andrena nigroaenea.

Anyone can see it is a cuddly little solitary bee, not a spider.

Like the Spider-orchids, other orchids are described by the animals we see in them - not the insects they attract. Growing out of the bank of the front drive I noticed a Man Orchid (Orchis anthropophora). It is mainly pollinated by small beetles and sawflies.

Indeed the flowers do look like little men - with cycling helmets.

Entering the height of summer, in June, a few Lizard Orchids (Himantoglossum hircinum) sprouted next to the ageing Bee Orchids on the front lawn. They are not pollinated by lizards (though there are plenty close by) but are believed to be food-deceptive, given off an attractive scent to attract mainly bees - but not providing nectar. The latin name hirsinum means 'smelling like a goat'.

The flowers really are reclining lizards. But with cycling helmets?

Just when it seemed summer was over, in September, large numbers of Autumn Lady's Tresses (Spiranthes spiralis) spiralled their way out of the front lawn and garden. Their fragrance, close to vanilla or almonds, attracts a wide variety of bees for pollination - and they are rewarded with nectar.

I used to think orchids were plants of nature reserves, requiring a special trip to protected places - but they are all around us. We have enjoyed eleven species in our garden alone. What will we see if we walk outside...?

Going native

Our land is now free of christmas trees. Time to plant some natives. At the side of the small hay meadow I planted an Elm (here in the foreground) and a Silver Birch (Betula pendula). 

Elms are a much rarer sight than they used to be. In 1910 they began to die. By the end of the century France had lost 97% of its trees. My elm tree is a symbol of 'girl power' in science. I have planted it on the centenary of the discovery of the cause of the disease that was killing the elms - a fungus called Ophiostoma - by an all female team in the Netherlands (thus 'Dutch Elm Disease`): Johanna Westerdijk (the first woman to become a professor in the Netherlands - in 1917, two years before she was allowed to vote), and her two PhD students Bea Schwarz and Christine Buisman. (I was once interviewed for a job at Glasgow University - the successful candidate was a woman working on the molecular taxonomy of elms, and I now wonder if she knew about the female Dutch pioneers).

The Dutch made an Ophiostoma resistance programme from 1928 to 1992, resulting in three highly efficacious cultivars - one of which is 'Nanguen', raised in Wageningen (the Agricultural University where I worked for two years). It is the cultivar most closely resembling native European elms. It was screened in France, where it is now sold under the name Lutèce ('Nanguen' is a contraction of Nancy & Wageningen). I have planted a 'Nanguen'. This cultivar is now being planted for butterfly conservation, namely of the White-lettered Hairstreak (Satyrium w-album) which only lays its eggs on elms. I'm not sure a single tree will attract them, but who knows.

Nearby I have planted a Rowan (Sorbus aucuparia). It should delight with its white flowers in summer, providing food for insects, and in Autumn its red berries will provide food for birds (aucuparia comes from the latin words avis for bird and capere for catching). 

Marianne wanted a Walnut tree. We do have a small one trapped in a hedge in the shade behind the house, but it will never realise its potential - given enough space and light a walnut tree can reach a height of over 30 metres with a trunk over 2 metres in diameter. I have planted a Juglans regia, the so-called Persian Walnut, a native from Europe to China, in the most open space of the front garden, in front of the large hay meadow. We are not alone - in France walnuts are the second orchard crop by area, grown on around 20,000 hectares, and we live in the most important region. I doubt we will be a major supplier of nuts, but we may sit on a bench under the shade of a magnificent crown.

I've also planted some fig trees (Ficus carica), each a different variety - the flavour and smell of the Mediterranean and Middle East. Figs like it sunny and dry. I've planted one by a south facing wall, next to the large hay meadow.

Another two figs are at the side of the potager meadow. I don't know if its the best site, but I live in hope.

Delicious fruit is not a reason to grow figs - because the part you eat is not the fruit, it's a fleshy pod inside which little male and female flowers bloom and form little true fruits when pollinated. The wonder of figs is their need to be pollinated by a fig wasp, Blastophaga psenes.

At the base of the flower pod is a hole. A female fig wasp will fly into the hole, carrying pollen from another fig, and lay her eggs in some of the flowers - whilst at the same time pollinating other female flowers. The wingless males will then hatch first and mate with females before they have hatched. The males will then dig holes in the pod for the females to escape, and then die. Male fig wasps never see the world outside a fig pod. The females fly out, having collected pollen on their way - and the cycle continues. You couldn't make it up!

Postscript:

Back in Basel for Chistmas, I take walks in my local wood - an ancient wetland, now canalized. There, lining a stream, are a number of large elms. One of them has recently been labelled. It says the tree is a White Elm (Ulmus laevis) that is between 200 and 250 years old. This is a species of north-eastern Europe, that reaches its western limit in Switzerland. It is one one of the few elms that can tolerate watterlogged conditions (as this area would have been when these trees were saplings) and it even relies on flooding to transport its seeds. 

A characteristic of the species is that the leaf veins beyond the lobe are undivided.

I can hear you shouting at your computer screen "but Dutch Elm Disease killed all the big elm trees!". Well, many White Elms did not suffer from the disease - not because they are resistant to Ophiostoma, but because their bark contains a chemical called Alnulin which is distasteful to the Elm Bark Beetles (Scolytus species) which carry the disease. The beetles would rather feast on Field Elms and Wych Elms.

The answer to the question 'when is the best time to plant a tree' is 'twenty years ago'. But really, it's never too late to plant a tree - as long as it's a native.

Fruits of my labour

I spent most of my working life in the world's most important orchards: apples in Italy, France, USA, South Africa; pears in Belgium, the Netherlands; oranges in Spain, Italy, USA, Brazil... I was even given a job in my company as head of fruits for Europe. So, now that I have the space and time, I thought I should have my own orchard. I decided on the traditional old faithfuls, apples and plums.

The Apple (Malus domestica) originated in Central Asia, where it was domesticated from wild M. sieversii. The unusually sweet fruits were selected among the many species of sour wild 'crab' apples. Seeds would have been transported west to Europe along the silk road, and hybrids formed with native species along the way, including the Wild European Crab Apple (M. sylvestris). Such was the importance of the apple, that in the ancient Middle East it was used as the fruit in the creation myth of the Garden of Eden.

Apples have a lot of genetic variation. When two trees cross-fertilise, the young trees which grow from their pips will inherit the characteristics of both parents - looking different from both, and from each other (just like us). Since ancient times humans have used cross breeding to create new 'varieties' which are unique, for example in looks, taste, and timing of flowering and fruiting. However, this genetic variation also means that once a cultivar has been selected its characteristics will degrade when it cross-fertilises with another tree. To solve this, ancient Asian societies invented 'grafting' - a stem (scion) is simply cut and attached to a rootstock (the underground part of the tree), onto which it will grow into a 'clone' of its parent.

Rootstocks are the engines of trees, and their genetics will effect how big a tree will grow and where it will grow best. For agriculture to advance, farmers would need to be able to obtain reliable rootstocks with predictable properties best suited for them - as investing in a slow growing tree is a big risk. Enter Sir Ronald Hatton.

A Londoner by birth, Hatton was nephew of the famous statistician Karl Pearson (the founder of mathematical statistics). He studied history at Oxford but, after subsequently working on a farm, realised his true vocation and went to study agriculture at East Malling Research Station at Wye in Kent (where he would become director, and also publish a book titled 'Folk of the Furrow' under the nom de plume Christopher Holdenby). From 1912 Hatton catalogued apple rootstocks, numbering them in a series after the letter M for Malling. They became the international standard for apple production. Later, in collaboration with the John Innes Institute at Merton in South London (a few kilometres from where I grew up), aphid resistant varieties were developed which were designated (you guessed it) MM. Commerial apple orchards usually plant rootstocks for small trees (low M numbers), to be grown at high densities, which are trained and pruned heavily for convenience of management and to maximise quality and yield.

I'm not planting an orchard to make money or feed the world. I want to witness the magnificence of an apple tree fulfilling its genetic potential, and enjoy all the wildlife which that should bring. Hatton and his cloned M rootstocks are not for me. There is an alternative - seedling rootstocks (called franc in France), grown from apple pips. They have more genetic variation and are very vigorous - scions grafted onto them will grow into trees of over six metres in height, with the lowest branches around two metres from the ground.

The European Plum (Prunus domestica) is thought to have originated in the Middle East, as a hybrid of the Cherry Plum (P. cerasifera) and the Blackthorn (P. spinosa). In Europe there are four main plum groups: typical European Plums (from Eastern Europe, such as the Quetsche), the Agen Prune Plums (natives of my region, and the most economically important), Reine-Claude (named after the French 16th century Queen and imported into England as Greengages), and the Mirabelles (small often feral fruits used for jams). Plums also have a seedling rootstock - Myrobalan, grown from the pips of ancestral Prunus cerasifera. Trees grafted onto this rootstock can grow up to six metres in height.

Before the 20th century, most orchards had trees of this size. Today they are a rare sight, and their days are limited because, like humans, 100 years is an exceptional age even for big trees. In these ancient orchards, as in sparse woodlands, the open spaces around the trees were carpeted with wild flower meadows where, after the summer hay cut, livestock grazed under the high branches - captured here by British artists Nicholas Verrall and Janet Fischer.

It's a pretty bucolic scene, but in reality livestock can damage tree bark by rubbing against it and they will fertilize meadows with their feaces to the benefit of grasses over wild flowers - and I think there are too many domesticated farm animals in the world anyway. Probably better to substitute them with a scythe and a mower, using the standing space below the canopy, and enjoy visits from wild deer. The fruits of these trees need to be harvested by ladder, or collected as windfalls for cider, or just left for the wild birds, insects, and mammals to enjoy.

Having decided on my rootstocks, I had to choose the scions. There are over 7,000 varieties of apples, yet in Europe only fifteen make up 75% of the apples consumed - those that are uniform and easy to produce and sell. Leading these is the Heineken of apples, Golden Delicious.

Again I want genetic diversity, and I want varieties that were selected for local conditions with a unique history and character. I prefer to drink Westmalle Tripel. I'm a paid up member of CAMRA - the Campaign for Real Apples.

Local varieties on seedling root stock are not found at the local garden centre. In my region, Aquitaine, the place to go is the CVA in Agen - their mission to 'safeguard old fruit varieties of regional heritage'.

I chose twelve varieties of apples newly grafted onto franc, and three of two year old plum scions on myrobalan. I made sure that the varieties were as 'rustic' in character as possible, including those specifically suited to be eaten fresh, cooked, or made into cider. I also ensured that they would be spread over the year in flowering (for cross-pollination) and fruiting (for harvesting).

I then planned the orchard - a series of rows with 6 metres between the plum trees and 10 metres between the apples.

A lot of people think that planting an orchard just requires digging holes and plonking trees in them - they don't realize the skilled workforce and sophisticated equipment that is required.

In January, Marianne and I dug holes and plonked trees in them.

Once the trees were planted, we fenced in each with a 1.3 metres high wire mesh to prevent nibbling by the roe deer which come into the garden most nights. The final result looked a bit pathetic - a far cry from the ancient orchards of oil paintings.

The power of nature. By summer the orchard was already beginning to look like an orchard. All the trees produced healthy shoots and leaves. I mowed and mulched the rows through the year to return nitrogen into the soil. The meadow between the rows was left to be cut by the farmer for hay in mid-summer, and for the rest of the year I mowed it but took the cuttings away for composting - to remove nitrogen to keep the grass low and to encourage the Spring flowers.

One of the Quetsche even produced some fruit.

Nature works at its own pace. After five years my baby apple trees should become adults and bear fruit. In ten years they will enter the potency of maturity, then age into mellowed and wrinkled gentle giants. They will dress in lichen, and allow birds to pick twigs and nest in the safety of their huge canopies. And they will be joined by the laughter of children, climbing and swinging from the strong arms of their branches in the shade of the endless summer days of their adult reminiscences. And the old folks will look on with their Westmalle Tripels, and they will say that it was good.