April 23

Gardens of the High Line by Piet Oudolf and Rick Darke

ELEVATING THE NATURE OF MODERN LANDSCAPES

This is such a fantastic book if you like the look of the High Line Gardens. These are gardens in new York created on the old railway line that is elevated above the city and was descending into disrepair since its closure. Some far-sighted person envisaged a garden and together the landscape architects James Corner Field Oprtsyiond, Diller Scofodia + Renfro and gardener Piet Oudolf created a vision and plan that became reality.

The book is a picture book of the gardens on the High Line throughout the seasons and it shows the hard landscaping and the planting working so well together. I think it is possibly my most favourite garden that I haven’t visited of all time (at the moment) because I love the hard edges of the landscaping and the wild planting.

Photo by Richard Darke

There were two things I took from the book for my garden. Firstly, always be able to articulate the vision and principles for the garden. I am well aware of doing this in my work but hadn’t thought about it from a gardening point of view and it is true. The beds in my garden or on the wildlife plot that are the least successful are the ones where I am not sure what I am doing in them. On the wildlife plot the names of the beds are sometimes a shortcut to what I am doing with them – The Grasses Bed – but I have one unnamed bed that I just stick all the leftover plants in and it looks a mess. At home in the garden I am slowly moving to be a bit wilder and this needs articulating about what I mean for each border and bed and the garden as a whole.

Photo by Richard Darke

I love the way the tracks have been relaid and the planting appears through them in parts of the garden. Some of the tracks have also been used as sculptural items and I like that too. Context is everything here – the context being industrial but wild land.

An example of articulating the vision of the garden is of the Chelsea Thicket. Here a sense of enclosure was required with fragrance playing a key part of the experience. The ground is to be covered in a carpet of herbaceous plants that act as a mulch and prevent weeds from becoming too prolific. This has been achieved through the planting of trees that enclose area and then shrubs such as viburnum, winter hazel, fothergilla and witch hazels to name a few that provide the fragrance. Underneath these are planted sedges, hakonchloa, spring vetch and fumewort. This is a classic layered woodland.

The most essential skill to possess, whether designing or conserving layered landscapes, is the ability to observe and articulate the patterns

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The second thing I took from the book are plants to try out – I garden on sand and therefore some of the limitations they have on soil depth and dryness make the plants quite suitable for me. Once I have worked out and articulated the vision for my gardens and beds, then I will go back through the book and identify some plants to try. Easy to try plants would be spring vetch (Lathyrus vernus), Frosted Violet coral bells (Heuchara ‘Frosted Violet’) and sedges (Carex bromoides) as an understory.

This is a book I will return to time and time again, to lose myself in the pictures and to try and recreate a small part of it in the soil I tend.

December 24

Wilding by Isabella Tree

A volunteer who works with me on the wildlife plot suggested I read Wilding: The return of nature to a British farm by Isabella Tree. I hadn’t heard of this book but it was highly commended by the 2019  Wainwright Book Prize and so there is no time like the present to get started on it.

It is a fantastic story about wilding the Knepp Estate,  a mixed farm, which through grants and lack of money became the most amazing return to nature with a little help from the owners. The one thing the book does really well is show the inter-connectedness of everything. So, rather than write the normal sort of review, I am going to record some of the elements which were new to me or amazed me.

  • I didn’t know about the relationship between oak trees and jays. Jays eat acorns but also store them. They peck and push them far down into the soil – in fact to the very distance that is most propitious for an acorn to sprout. During the summer months they leave the acorns as there is plenty of other food but then eventually return. By now the acorn has sprouted so the jay pulls it up just enough to get to the cotyledon leaves which remain underground. Because the oak sends down strong roots very early in its life, it is often strong enough to withstand this attack and will carry on growing. If that isn’t enough, the jay will bury the acorns at the edge of scrub plants and these continue to grow and eventually provide a thorny tree guard for the oak, preventing cows, deer and other grazing animals getting to it. So, not only does the jay get a carbohydrate rich food, but it plants the seeds from which the next oaks will grow. In a four week period a jay can bury about 7,500 acorns. Why aren’t we allowing jays to do this for us instead of recruiting hundreds of volunteers to plant trees that need plastic guards?
  • By not using herbcides, pesticides and any other cide on the farm the number and type of dung beetles increased dramatically. In fact the owners timed how long it took for beetles to arrive at a newly deposited pile of dung and it was three minutes. Using wormers and paratiscides on cattle kills the dung beetles or any other insect that eats the dung. Because dung beetles tunnel, this has an impact on the quality of the soil reducing the aeration, fertility and ability to soak up water. But even better, the dung beetles reduce the parasites in the dung by eating it up quickly and therefore reduce the amount of wormers needed. And of course, if you use wormers, it reduces the beetles and other insects which then has an effect on the birds and so on up through the food chain.
  • Honeysuckle provides nesting material for doormice. I didn’t know that and we don’t really have any, honeysuckle or doormice, on the wildlife plot so need to take some cuttings and grow some if only for the scent.
  • Credit – Getty images

    What comes through loud and clear in the book is something Tree refers to as ‘species-shifting syndrome’ as exemplified by nightingales and purple emperor butterflies. Nightingales are often referred to as a woodland species but left to their own devices at Knepp, the nightingales have nested in wide, prickly hedges and open-grown scrub both of which are rich in insects, not woodland. Could it be that they are seen in coppiced woodland because they are clinging on to a habitat that is present, not their preferred but the least worst thing. Time and again, Tree says that if you look in wildlife guides over a 100 years ago the range and type of habitat described in them is different to the modern guides. If we take the modern guides at face value we would be planting lots of coppiced woodlands to encourage nightingales but it wouldn’t. They cling on to these as a last hope not actively choosing them as their preferred habitat. She demonstrates the same with the butterflies and suspects the same thing with collared doves.

  • If you want to increase biodiversity allow herbivores on the land. They create a biodiverse ecosystem from a blank slate – just one species will do but if you have more then there will be an even bigger effect. One example given in the book is in Nigeria where cattle grazed with donkey’s put on 60% more weight because the donkeys graze the tough, upper portion of the grass revealing more delicate parts for cows. This also happens slightly closer to home on Dartmoor where the wild ponies eat what they like, leaving close cropped grass for other herbivores such as free-roaming cattle and sheep. What they leave behind is ideal habitat for marsh fritillary butterflies.
  • Islands of wilding are not enough. We need corridors and more, bigger and better sites.

This is such a fantastic book, jam-packed full of interesting, slowly evolving rewilding observations. The big take away from it is that nature does it best; not the big, well-known conservation groups although they have all done other good things. It is their lack of ability to take risks and to be at the forefront of different ways of working that is quite frustrating.

All I can say is the winning book of the Wainwright prize in 2018 must have been excellent.

 

March 21

10 things I didn’t know about soil

I was given  a couple of books for Christmas about soil. I read the fun-looking one a while ago but left the more serious one, Teaming with Microbes by Jeff Lowenfels and Wayne Lewis,  and have only just got round to it. It turns out that you shouldn’t judge a book by its cover. I learnt masses from the second book so here are my top 10 amazing facts.

  1. I have heard plants being called fast carbon pathways but haven’t ever really understood why. It turns out that as a result of photosynthesis, carbohydrates move back down a plant to the roots and then drip out of them. These carbohydrates and proteins that come out of the roots are known as exudates and are what attract the fungi and bacteria in the soil to them.  Bacteria and fungi are eaten by protozoa and nematodes and their waste is absorbed by the plants as nutrients all of which happens in the rhizosphere which which is about 1mm around the root system of a plant.  I like the analogy that is used in the book of bacteria and fungi being the small bags of fertilizer and the protozoa and nematodes act as fertilizer spreaders. All of this is controlled by the plant. Soil life provides the nutrients needed for plant life and plants initiate and fuel the cycle by producing exudates.
  2. Some plants prefer soil dominated by bacteria, others by fungi. I knew that there are organisms in the soil but I didn’t know that plants had preferences.
  3. Most vegetables, annuals and grasses prefer soil with more bacteria and their nitrogen in nitrate form.
  4. Most trees, shrubs and perennials prefer fungally dominated soils. In general, the longer a plant stays in the soil, the more it likes a fungally dominated soil. It make sense really. Annual plants are over in a year or less and that isn’t conducive to the hyphae on the fungi having enough time to grow and spread out.  In fact, the bacterial numbers in the soil stay the same, it is the fungal numbers that increase.
  5. The compost that we add to a soil inoculates it with the micro organisms in it. The aged brown material we add feeds the fungus and the green stuff provides the sugars for the bacteria. Kelp and rock dust can be added to compost heaps and they provide food for fungal growth.
  6. Worm compost is rich in bacteria with very little fungal activity. That makes sense. The worms eat the scraps we put in and the microbes in their digestive system break them down. It is therefore best used on annual vegetables.
  7. Bacteria need more moisture than fungi and work quicker if the materials are ground up or shredded. This fits in with making the 18 day compost using the Berkeley method (which I still haven’t mastered yet!).
  8. The best way to support fungi is to spread a compost made with more brown material than green with the addition of rock dust if you have it. After this has been spread you could then mulch with wood chippings which will break down more slowly. I was thinking about raspberry canes when I read this.
  9. There are two types of mycorrhizae: ectomycorrhizea and endomycorrhizae and plants prefer one rather than the other. Ectomycorrhizea grow around the roots of a plant and surround them, endomycorrhizae  grow into the cells of the roots of a plant. Some mycorrhizae can act as ecto with one plant and endo with another. Fascinating and very flexible!
  10. It is worth using mycorrhizal fungi when transplanting all plants other than brassicas and chenopodia (spinach, beetroot etc). They do not utilise mycorrhizae.

There are a variety of actions that can develop bacteria and fungi in the soil – adding compost, mulching (or combine the two and mulch with compost!) and using actively aerated compost teas. I am still getting my head around these teas – they involve an air pump or being stirred for hours and so are not for the faint-hearted.  What is easier to understand are the actions can damage the soil food web.

  • Digging the soil will break up the rhizosphere, the hyphae on the fungi and destroy the structure of the soil created by the micro-organisms.
  • Chemical fertilisers, insecticides, pesticides and fungicides affect the soil food web being toxic to some organisms, warding off others and changing the environment. When plants are fed chemically, the bacterial and fungal relationships with the plant are not formed, the microbial populations reduce as a result and the plant then needs constant chemical feeding.

If you are interested in the soil food web, Dr Elaine Ingham is the queen of this science and her How it Works videos explain the processes much more clearly than I can.

I am going to have to read the other book written by Lowenfel and Lewis – Teaming with Nutrients.