Ferns and other inconveniences

The local paper is up in arms! A hypermarket had bought a patch of land next to its store to expand its activities at a total project cost of 15 million Eurors, only to be told it cannot proceed because of the existence on the site of a wild fern, Ophioglossum vulgatum.

This plant is not especially uncommon in Europe but has protected status in several areas, including the Sologne, on the edge of which the hypermarket is located. The Adder’s-tongue Fern is an unusual fern that grows in old grasslands, on hillsides, along woodland rides and on sand dunes. It usually appears between June and August, spending the rest of the year underground as a rhizome. Looking more like an Arum than a fern, it is considered a good indicator species of ancient meadows and can be found alongside Common Spotted-orchids, Quaking Grass and Devil’s-bit Scabious. For centuries it has been used as a treatment for wounds, using a preparation of it known as the ‘Green Oil of Charity’.

Ferns (but not this one) are one of the solutions recommended in Graham Rice’s new book, “Planting the Dry Shade Garden”. Billed as the only book deal with this growing condition, I was interested to read what was advised, having several dry-shade areas in my own garden. The book starts by discussing the nature of the problem of planting against shady walls or under trees. It goes on to explain how to improve the situation by reducing shade and increasing the amount of available moisture around trees. Crown thinning, crown thinning and tree removal are suggested options to increase light levels while a range of techniques are available to improve fertility and soil moisture content.

Planting the dry-shade garden - Graham Rice

In dealing with the soil the suggested actions are to raise soil levels, improve soil quality, install irrigation and mulch regularly. Container planting is also proposed. Increasing soil depth is a common but controversial technique, and one which may have your local authority tree officer rushing ’round to intervene. Few trees can confidently be predicted to thrive or even survive if more than four inches of fill are placed directly over their roots, so great care must be taken when gardeners construct raised beds as suggested. The rule of thumb is to preserving the existing levels in a circular area around the tree, equal in diameter to at least one-foot for every inch of stem diameter. This means that I should protect an area of 100 feet (30m) around our 150 year old Sequoia which is 8ft 4″ (2.55m) in diameter!

The other issue not discussed here is the serious harm which may be done to trees by planting amongst their roots. Regular cultivation of the soil can also remove or damage delicate feeding roots and introduce soil-borne diseases, so a high degree of care must be taken when gardening under trees.

As Graham Rice points out, what can be grown in dry shade depends on how bad the problem is – after all, some on the world’s finest gardens are woodland gardens. The main part of the book describes a range of plants suitable for the toughest conditions, a source of inspiration to those gardeners who have about given up hope with their own shady areas. Around 130 plants are listed and illustrated, with descriptions written in a style that suggests he knows them personally. The well-illustrated sections are divided into Shrubs, Climbers, Perennials, Groundcovers, Bulbs and Annuals and Biennials. We already have a few of the plants suggested in our bed under the Sequoia and  in the shade of the neighbour’s Lawson Cypress, but I am happy to say that I learned a thing or two and plants I might have not considered were brought to my attention. It is the nature of such a book that a few of my favourites were left out, while some of the suggestions would need controlling if they were not to take over more favoured parts of the garden.

All in all I would recommend this book to gardeners of both the armchair and the hands-on kinds. It is written by a well-respected and knowledgeable plantsman and aimed at garden owners on both sides of the Atlantic. At just over £10 from the Garden Design Academy bookshop, it could make an ideal stocking filler this Christmas.