In the days when the great plantsmen were exploring the previously uncharted mountain areas of China, Bhutan, Sikkim and the like, new finds were being sent back to their sponsors and were soon introduced to the botanics and the 'great' gardens of Britain. Many of these, Rhododendrons, Camellias etc.-were found in acidic soil and it was necessary to simulate that environment in cultivation.

As a result, peat, with its ability to neutralise alkaline soils, was used extensively as the medium for these plants and, as one would expect, they flourished….and so The Peat Garden was born.

THE CONTROVERSY FACTOR:
For many years, the Peat Garden was a feature of the larger gardens in Britain and long before the days when conservation gained importance, the harvesting of peat for domestic use was a large commercial venture. Today, the depletion of the habitat of some of the most endangered flora and fauna is, justifiably, causing worldwide concern. Gone are the days when peat blocks were transported the length and breadth of the country but there is still considerable peat extraction taking place which will, if left unchecked, cause the extinction of many of these islands' rarest treasures before the next century has time to take a foothold.

So why then, do you ask, am I advocating growing plants for the "Peat Garden?" As an author, and a plant lover, I feel there is a sense of responsibility on my shoulders to put both sides of the argument. There is obviously a lot of concern from conservation-minded people about the exploitation and overfarming of peatlands and I feel it would be remiss of me to advocate the use of peat in gardening without at least making reference to the other viewpoint.

One of the advantages of living in a rather dank and wet climate (although even this is changing by the year), is that it is possible, even advisable, to grow members of the Ericaceae family. They have few requirements to prosper - an acid soil, moisture at the roots (they must never be allowed to dry out), good drainage and a position in good light which, although not a prerequisite to flowering success, is nevertheless beneficial. The first three conditions, if not catered for by your natural environment, can be manufactured to encourage successful cultivation of this fine family of plants. If you plan on growing Rhododendrons, Kalmias, Gaultherias and the like, it is imperative that you test your soil for its hydrogen potential (ph). This can be done very easily with a test meter or a chemical analysis kit, both of which can be purchased for a small sum of money and both of which are readily available at nurseries and sundries establishments. You should, if you are lucky, record a ph level of between 5.5 and 4. Anything higher is likely to contain too much lime and anything lower is likely to be too acidic. If you find that your soil is acid, then you have no need to worry, members of the Ericaceae family will happily grow for you.
On the other hand, if you determine that your soil is alkaline, then to plant ericaceous plants would mean the kiss of death. The lime content in the soil would poison the plants, the leaves would go yellow (chlorotic) and the plants, if they did not die in the first season, would perform very badly before eventually giving up the ghost.
So what can be done…..As with most forms of gardening, there is no simple answer. It takes a great deal of thought and a great deal of preparation. In order to cultivate these plants successfully, you will need to provide their basic requirements of
1. Acid soil
2. Moisture retention
3. Excellent drainage and
4. Good light…….(this does NOT mean full sun).
To take these requirements a step at a time:

ACID SOIL
As stated earlier, a ph of 4-5.5 is ideal. Composted bark, pine needles and leaf mould, providing they are from plants already growing in an acid soil, are excellent for modifying an otherwise high ph level and will contain many more nutrients than peat itself.
MOISTURE RETENTION
A soil containing the above ingredients should, providing it is never left to dry out, have sufficient moisture levels to maintain the plant life.
DRAINAGE
Very few, if any plants, will cope with being permanently starved of oxygen at the roots. To this end, a proportion of drainage material should be incorporated into the compost at mixing time. It goes without saying that this too must be lime free.
ASPECT
Good light, as opposed to strong sunlight, will benefit the majority of ericaceous and allied plants. Good planting schemes can however accommodate areas of shade when deemed necessary and the whole object of providing shade is to ensure that the plants (a) do not dry out and (b) do not scorch in the full heat of the sun. Use shade wisely.

Having established that you can provide the plants with these conditions, you can refer to the list of plants given below. However, should you have determined that your soil level is too alkaline, do not despair. Many alpine plants are grown in raised beds, so why not ericaceous plants? It is possible to build a raised bed with stone, timber or whatever else fits in with your general landscaping style. Remember though, no waterworn limestone, as beautiful as it may be. The bed should have a depth of say 60cm. This should ensure that any lime in the soil will not find its way into the roots of your plants. The remaining dimensions are entirely up to you. Consider how much fill you will require to complete the bed (take into account the shrinkage factor) and then decide the length and width of the raised bed.

And now to the plants…….. Many excellent books and articles have been written on the subject of plants for the Peat Garden. So many in fact, that to list a selection of plants without duplicating the work of other authors would be nigh impossible. Suffice it to say, that those with an avid affection for these plants, will endeavour to grow as many of them as space allows and consequently have very similar tastes and affinities. I will for the purpose of this article list them in alphabetical order of genus and where I can, will suggest possible sources for the plants.

Dwarf Shrubs

Andromeda:

Dwarf shrubs, ideally suited to the smaller garden or peat bed, which flower in May and June. Ones to look out for are A.glaucophylla from N.America with terminal clusters of the palest pink flowers. A.polifolia (The Bog Rosemary) is commonplace in the Northern hemisphere. It has glaucous leaves which are white underneath and amongst its many beautiful forms can be included, 'Compacta', which as its name implies is a compact form with bright pink flowers.(there is also a white form of 'Compacta' which is equally beautiful in flower), 'Minima' which is a near-prostrate form and 'Shibutsu' another compact plant with many soft pink flowers.

Arcterica

This is a monotypic genus, the species being A.nana. A rather diminutive plant from Japan with a profusion of white urn-shaped flowers in April and May. There is also a form with red stems known as A.nana 'Redshanks' which has been available for a number of years.

Arctostaphylos

The 'Bearberry' a large genus with many species from N.America, some much too large for the small peat garden. Of those more suited to the smaller garden, myrtifolia, nevadensis and uva-ursi should be sought after for their prostrate habit and ground cover capabilities. The 'Black Bearberry' Arctostaphylos alpina is now better known as Arctous alpinus, a gem of a plant for habit (very low and dense), foliage (dark green, bronze and red) and flower (terminal clusters of white urn-shaped flowers with just a hint of pink).

Arctous
(see under Arctostaphylos alpina)


Cassiope

This genus is so widely grown, that it would be impossible to list them. C.fastigiata, lycopdioides, tetragona, selaginoides and wardii are amongst the best species for this type of culture, whilst "Edinburgh", "Muirhead"and "Randle Cooke" are extremely rewarding hybrids, which will also take kindly to pot culture.

Gaultheria

This is a very large genus consisting of shrubs from every Continent, many of which are suitable for a peat or rock garden.I should point out at this stage that the genus is listed as a poisonous plant. G.adenothrix from Japan, is a dainty little thing with red stems, dark green leaves and pink flowers which will spread comfortably without being a nuisance. G.cuneata, which is my personal favourite hails from China and has shiny green leaves and not insignificant racemes of pure white flowers followed by gleaming white berries to match. This is a beauty, compact and hardy.G.procumbens is one of the most readily available species. From N.America, this small shrub makes an excellent evergreen carpet of dark green and bronze leaves, covered in bright red berries throughout the winter months. The flowers, white tinged with pink, give an excellent show during the early summer. Another gem, although of doubtful hardiness in all but the mildest regions is G.trichophylla with its abundance of rose flowers over tufts of bright green foliage. In the winter, the foliage can turn almost red and is covered with berries of the brightest blue.Indispensable if you have the climate.Recent introductions from S.America include Gg angustifolia and mucronata, with berries in shades of white, blue and pink and are ones to try for the future.G.depressa from New Zealand and G.hispida from Australia are other members of the southern hemisphere Gaultherias worth trying.

Gaylussacia

This is a mainly N.American genus with small and dwarf shrubs in it's repertoire. One of the dwarfest and most outstanding is G.brachycera, whose greatest claim to fame is it's foliage of autumn tints.

Kalmia

Much in demand for the acid garden, most of the Kalmias may be a little on the tall side for many gardens, however there are some incredibly beautiful compact forms in cultivation and you should seek them out. Amongst the finest is K.angustifolia rubra nana. This is both compact and shapely and in early summer has the most gorgeous bright-red flowers in abundance. Kalmia latifolia too, whilst too large for most gardens does have some dwarfer forms. Try "Little Linda", whose buds are of the brightest red, opening to give bright pink flowers in the summer sunshine. "Galaxy" has stellate flowers, whilst "Silver Dollar" has the largest flowers of all-and pure white at that. K.microphylla is a true alpine species, only 15cm in height and a real treasure.Deep rose coloured flowers in summer make this an absolute joy to behold. And finally, K.polifolia, the Swamp Laurel from a vast area of the USA including the Rocky Mountains. A small shrub from 30 - 45cm high with rose-coloured saucer-shaped flowers throughout the summer.

Kalmiopsis 

Restricted to a single species, Kalmiopsis leachiana is one of the real treasures of the peat garden. Kalmia-like flowers of deep rose-pink cover the plant in spring to the effect that it is difficult to see the foliage. One of my plants (see Photo Gallery 3) has bright pink flowers and much reduced foliage size. A very compact and fine shrub. There are some plants from different locations in Oregon, the best known being K.leachiana M.LePiniec and the Umpqua Valley (soon to be named K.fragrans) form. In the last few years, other forms have made appearances including K.leachiana 'Shooting Star' with stellate flowers and K.leachiana 'Appleblossom' with pure white flowers.

Leiophyllum

Leiophyllum is related to the similar genus, Ledum , from which it differs by its leaf shape. L.buxifolium as its name implies, has leaves similar to those of the box tree (Buxus) but there the difference ends. This small, neat compact plant has a profusion of white flowers in the early summer and the form 'prostratum' is smaller and obviously more prostrate but equally floriferous. 'Compactum' shows all the characteristics of L.buxifolium but on a more diminutive scale. All these make excellent plants for the smaller peat bed.

Loiseleuria

The Mountain Azalea...L.procumbens is a real gem, that is if you can get it to flower in cultivation. This very shy-flowering beauty is a native of Scotland and other parts of the Northern hemisphere. A recent introduction from Japan has proved to be more amenable in cultivation and this has been seen with so many pink, bell-shaped flowers as to obscure the very tiny leaves. A must if you can find a good flowering form.

Menziesia

One of the largest of the 'dwarf' shrubs covered in this section (it reaches 1m tall but it is slow growing and well worth its place in the garden), M.ciliicalyx is a deciduous shrub par excellence.With late spring flowers of cream through to purple, borne in trusses all over the plant this, together with its form M.ciliicalyx purpurea will delight you.Another exceptional plant from Japan...how do they do it?

xPhylliopsis

Bi-generic hybrids out of Phyllodoce and Kalmiopsis and sharing the charms of both parents. The most widely grown is "Pinocchio" with long arching stems of pink flowers in spring. Other recent hybrids (and they seem to be appearing on a regular basis) include "Coppelia" ,"Hobgoblin" ,"Sugar Plum" ,"Puck" and "Mermaid" all of which are excellent peat bed plants.

Phyllodoce

The Phyllodoces can be either easy or demanding dependant, apparently, on whether they are happy where they are! How one accommodates an attitude like that is beyond my reasoning but they are certainly worth the extra cossetting they demand. P.aleutica is a choice plant with clusters of yellow urn shaped flowers and an excellent foil to the many pink and white flowers that appear at the same time of year. P.breweri from N.America, is larger than the aforementioned and carries pink kalmia-like flowers of a bright rose pink. It can spread quite nicely but never invasive. One of the easier ones. Another yellow flowered species is P.glanduliflora, also, from the USA, rarely seen in gardens but worth seeking out. It, together with P.empetriformis are responsible for a range of natural hybrids which are identified as P.x intermedia. "Drummondii", one such hybrid has masses of crimson flowers in late spring. Vigorous and relatively easy to please. P.nipponica, a choice little shrub from Japan forms clumps in the peat bed and when happy with its lot will produce masses of pure white flowers in Spring

xPhyllothamnus

Another bi-generic hybrid, the parents, Phyllodoce empetriformis and Rhodothamnus chamaecistus, giving rise to xPhyllothamnus erectus and a special plant it is. Masses of bright pink flowers, hanging in umbels from the tips of the branches in late spring. More amenable to cultivation than either of its parents.

Pieris

Some of the species and hybrids are possibly too large for all but the largest peat gardens but there are a few that will light up the garden with the incredible colour of their young foliage and the abundance of white flowers on long panicles. Of those, I would recommend, P.japponica 'Mountain Fire' with brilliant red new growth, P.yakushimensis whose new foliage is a golden-orange and the even dwarfer P.yakushimensis 'Brookside Miniature'.

Rhododendron

Well, where to start?........
If ever there was a genus that deserved the accolade "every garden should have one", then this is it. From the giants of the Himalayas to the minutest creeping dwarfs, the Rhododendrons have something for everyone. I could not possibly list every one suitable for the peat garden in the limitations of this page and so I will try to list those with the broadest range of form, flower colour, leaf indumentum and special character. Be tolerant of my whims....if a 1000 people read this (I should be so lucky), I will guarantee that each of them will have their own favourite which I have omitted from the list. My apologies for the omissions but perhaps some of my favourites may well turn into yours.......and vice versa.

PLANTS ATTAINING A HEIGHT OF 90 - 150 cm.
(....and for the purists, I make no apologies for listing a majority of hybrids).

R.yakushimanum....what a stunner this is. It's got everything. Silvery new growth, dark green leathery leaves with orange-brown indumentum on the underside, compact habit, dome shaped, flowers in trusses changing from pink in bud, to white suffused with pink and then to white.No wonder this has parented a vast range of new hybrids. A caveat here though. This plant must be deadheaded annually to get the best results. I say must because it is recommended that all Rhododendrons should be deadheaded annually...but who has the time to do this..and anyway, I've never found it to be absolutely necessary, other than with R.yakushimanum.
Of the hybrids, 'Bambi' has the leaf indumentum (not all the offspring have it) and flowers which are deep rose-pink in bud, opening to rose-pink and ageing to cream suffused with pink. Very floriferous and long lasting. 'Caroline Allbrook' has frilly lavender flowers and is probably the best of this colour. 'Titian Beauty' is a classic red and is very free flowering with excellent indumentum, while 'Grumpy' is a pale yellow to cream form.There are a couple of white flowered hybrids but they haven't got a hope of competing with the species.
Other good garden plants of this height include R.'Nancy Evans' a free-flowering hybrid raised in America and bearing trusses of the deepest yellow bells and is, in my opinion, one of the best yellows around. A particular favourite of mine R.'Bow Bells' has a good compact habit, new growth which is bronze in colour and the largest, wide open flowers, of the richest pink, borne in loose trusses throughout April.......... and finally for this section, you could do worse than try some of the evergreen Azaleas (again with no apologies to the purists) but they are too numerous to name and are generally available from garden centres etc.


PLANTS ATTAINING A HEIGHT BETWEEN 30cm and 90cm

There are a number of Rhododendrons that are compact and stay well within the bounds of a raised bed. One of the best, R.'Curlew' is studded with lemon coloured flowers for weeks on end in spring. It is low growing and maintains a height c.40cm but with a much wider spread (see photograph at top of page). R.'Blue Tit' is an early flowering form upto 1m in height with lovely lavender blue flowers which become deeper as they age. R.'Pink Drift' is a little beauty of compact habit which covers itself with rose-pink buds opening to soft lavender in early spring. One of the earliest dwarf shrubs is R.'Praecox' which flowers for me in February and is awash with deep purple flowers. Of the whites, R.'Arctic Tern' excels. It is a hybrid of R.trichostoma and carries its many small white flowers in compact trusses. Upto 90cm and later flowering than most. R.primuliflorum, is without doubt, a must for every peat garden. Clear pink primula-like flowers cover the plant in late spring. I first saw this in an AGS show and fell in love with it immediately. Not too difficult but does require excellent drainage.

PLANTS ATTAINING A HEIGHT LESS THAN 30cm

There are a number of plants that will stay compact and low growing for many years. R. 'Alpine Gem' attains a height of 15cm and has many deep pink flowers in May. R.campylogynum is an unusual shrub with sempervivum-like rosettes but the real beauty of this is in the drooping thimble-shaped flowers which adorn it throughout early summer. R.campylogynum 'Claret' is a real treasure, reaching 40cmin time. My own personal favourite in the smaller class has got to be R.cephalanthum crebreflorum , a stunning plant with daphne-like cream flowers suffused with the palest pink. A real show-stopper. The prostrateR.radicans is another favourite forming mats of shiny foliage no more than 10cm high and carrying disproportionately large purple flowers in early summer.
There are so many rhododendrons to choose from that I have barely scratched the surface of what is available. Check your local nurseries for established favourites and for the new hybrids which are now regularly being introduced.

Rhodothamnus

One of the few members of the Ericaceae that will tolerate lime in its diet. R.chamaecistus grows on limestone formations in the Alps and forms carpets of tiny leaves covered in large, flat, rich pink flowers. This is not an easy plant to grow but well worth the effort. A delight in the peat bed.

Vaccinium

This is my final listing of ericaceous shrubs and I could not hope to do justice to the many wonderful plants that have been introduced from North & South America. Of the three I grow, V.macrocarpon 'Hamilton' is a carpeter with a vigour but it can be restrained with judicial pruning. The flowers are small and insignificant but the huge red berries are plentiful. V.moupinense is similar to V.delavayi but has mahogany coloured flowers and does not (in my experience) reach more than 60 cms in height. Autumn tinted foliage is an added extra. The cowberry V.vitis-idaea is a dwarf creeping shrub and its miniature form V.vitis-idaea minus is a little gem, equally at home in a trough or in the peat bed.

The above list is far from comprehensive and there are many more dwarf shrubs that will happilly grow in a peat bed. I have restricted my list to members of the Ericaceae but you must experiment and grow what you enjoy. As I said earlier, these are my personal favourites.....I would be pleased to hear about yours. Happy peat gardening.

If,as a result of this article, I have encouraged anyone to build a peat bed, or introduce new plants to their existing garden, then my work will have been worthwhile. I make no claims to being an "expert" - I am an enthusiast like yourselves. There may well be plants that you grow, not listed above, that you would like other people to know about....you may have some photographs that illustrate these plants....you may disagree with some of my comments. To this end, I would welcome any feedback from you. Please feel free to send your comments, good or bad and I will publish them and hopefully invite discussion.Thank you.

PHOTOGRAPHS ACCOMPANYING THE TEXT
Andromeda polifolia 'Nikko'
Gaultheria cuneata
xPhylliopsis hillieri 'Pinnochio'
Phyllodoce caerulea
Rhododendron 'Bow Bells'
Rhododendron nakaharae
Rhododendron yakushimanum
A View Of The Peat Garden
© Charles Johnson 1998


All other photographs © Alan Grainger 1998

Plant Associations In The Peat Garden by Charles Johnson

Nurseries supplying plants mentioned in the text