I found myself in Norfolk overnight attending the twentieth anniversary dinner of a company I've done a lot of work for over the years. Admittedly I featured more in their first decade than their second but it was nice to join in.
 Reader, there was revelry and a certain amount of drinking involved. I shall not write of such things but it falls within the scope of this diary to note that the venue was a fine old country house with walled gardens, a croquet lawn and sylvan glades.
 I rose early this morning and wandered down to the boating lake where I lingered awhile in tranquil contemplation. Then I returned to the house in search of strong black coffee.

 I saw this little plant growing out of mossy stones and stumps all around Heathercombe. I was trying to think which rare native flora it might be. Then the penny dropped- it's Pink Purslane (Claytonia sibirica), a plant from North America and Siberia that has naturalised in parts of the UK after being introduced as a garden plant.
 I have it in my own garden! But I didn't recognise it at first because it looks so thoroughly at home in the surroundings, much more vigorous, larger flowers and pinker in fact. Some plants like it tough; anything with the word sibirica in it is invariably very hardy. Dartmoor obviously suits it more than South London.

 A.R.T. part two. After Martin Crawford showed us the forest garden greenhouse he took us round the rest of the site.

 Adjacent to the greenhouse he is developing a low growing garden using forest gardening principles -without the tree canopy- as a prototype for smaller gardens. Living in London that's an approach I find particularly interesting. There is little scope for planting fully fledged forests in urban areas but there are many domestic gardens and public spaces.
 Strawberry plants carpet the ground; there isn't a patch of bare soil anywhere.   

 The Littlehempston site is exposed to the elements (that's the edge of Dartmoor on the horizon). Two forest garden staples form long hedgerow windbreaks: Sea Buckthorn (Hippophae spp.) and Autumn Olive (Elaeagnus umbellata). The former bears berries rich in vitamin C, the latter dark red fruits that can be eaten raw or cooked. Both are valued for their nitrogen fixing properties.

 

The hedges provide some shelter for several large scale plantings. The top photo shows the start of a new forest garden canopy layer. The yellow flowered Brooms are 'nursery plants', which Martin notes is a strategy used in forestry but not agriculture. Shrubs create shelter while the trees establish themselves.
 The second photo shows a planting of hazel in wide rows that will allow for 'alley cropping' i.e. combining agroforestry with polycultures of crops in strips. Elsewhere there are plantings of a nut orchard and experimental coppices i.e. trials of trees that are food producing and suitable for coppicing and pollarding. Martin is something of an authority on nut trees but points out there is no point planting them for food production in a locale where there are squirrels!
 The Littlehempston site is also where Martin does all his propagation and runs a mail order/internet business selling forest garden plants. Part three to follow...

 The woods, fields, hedgerows and verges in the valleys around Dartmoor were alive with wildflowers. Bluebells, Greater Stichwort and Red Campion were everywhere.
 Beautiful, but I particularly enjoyed seeing drifts of Cuckoo Flower (Cardamine pratensis). I have noticed them here and there in other parts of the country though never so many. The Cuckoo Flower is aptly named; the plant and the bird both announce the arrival of spring and I heard the call of the cuckoo throughout my five days at Heathercombe. 

 The Agroforestry Research Trust is the creation of Martin Crawford, a man who seems to possess indefatigable energy and ability. A drive through winding Devon lanes took the course to his Littlehempston site covering eleven acres near Totnes.
 His best known site is the two acre forest garden he has developed at Dartington Hall over a period of twenty five years. I wrote an entry about it recently (February 27th.) with examples of some of the general principles of forest gardening and Permaculture's ethos of creating food forests which generate a "permanent agriculture".

 Littlehempston is a somewhat different proposition and work began in 2011. It contains two new forest gardens, various large scale experimental plantings, nurseries and propagation beds and most intriguingly a sub-tropical forest garden greenhouse (as seen at the far end of the photograph above). It's pretty big as greenhouses go- intended to allow trees that grow as tall as six metres. 

  

 "Futuristic" is a word that doesn't seem entirely out of place here. The temperature is maintained by a 'climate battery'. In so far as I understand it the warm moist air of the daytime is circulated through underground pipes by fans warming the soil by conduction and condensating. The cooler air at night is circulated through the pipes which picks up heat stored in the thermal mass of the soil. The temperature is thereby regulated day and night- the re-circulated air has a cooling effect during the daytime preventing overheating of the glasshouse and a warming effect at night.
 I don't have a science background and I must say this is blowing my mind. The technology and research began in America and one of the leading proponents there describes it as "The magic of phase change from liquid to vapor and back again"!
 Electricity is used to power the fans overhead but the amount used is minimal whereas traditional greenhouses use a considerable amount of energy to maintain optimum temperature.

 Martin is clear that the greenhouse is intended for sub-tropical growing as there simply isn't sufficient daylight in the UK that's strong enough for fully tropical plants. I expect he will push the boundaries to see what is possible but as well as being a polymath he is a very practical pragmatist.
 I will have to make this part one of several entries about the Littlehempston visit because there was a good deal more to see. To be continued...

 Just back from five days on Dartmoor. The occasion was the second part of the Forest Gardening course which I began in February (subject of several entries back then). The High Heathercombe Centre overlooks one of the greener farmed valleys looking across to desolate hills beyond. The centre itself is perched by the edge of another stretch of bleak moorland and I took several walks into the solitude...

 The walks from Heathercombe point into the heart of the moor.

 It's fairly easy to get off the beaten track. Nonetheless there are beaten tracks which make rambling rather easier than hiking through the tufts and tussocks which resemble Sherlock's Grimpen Mire in places (though the moor seems pretty dry by Dartmoor standards at the moment).

 The remains of dry stone walls sometimes offer a viable route to follow.

 There was one sight I especially wanted to see. Years ago I saw an aerial photograph of Grimspound- the remains of a Bronze Age settlement surrounded by a circular boundary wall of about 150 metres in diameter. It's clearly marked on the OS map and as I approached the area I spotted it beyond a Tor ahead of me.

 So it was a real bonus to get some walking in but my main purpose for coming to Dartmoor was to continue the course. In particular it included a visit to see ART - the Agroforestry Research Trust - which I will write about in my next entry.   

 I'm heading off again to High Heathercombe on the edge of Dartmoor for part two of the Forest Gardening course (so there won't be any posts till early next week). NB Part one was the subject of several entries late February.
 The trip will include another session with Martin Crawford. Last time we visited his two acre garden at Dartington and he has others in the area which we'll be looking at this time round- including a glasshouse garden which sounds intriguing.