Saturday 17 August 2019

Wonderful wall shrubs

Andrew Collyer - Practical Gardening

Looking in gardens around the country you'd be hard pushed not to be impressed by the flowers being displayed by the Camellias at the moment. I think the last few years have been particularly good as far as this hardy versatile shrub is concerned.

Seeing all these Camellias reminded me of the fantastic wall trained specimen of Camellia 'Debbie' I had growing in my old garden in Dublin. It also made me think of how the art of growing wall shrubs has diminished. The popular Pyracantha, widely grown for its white flowers and a heavy crop of red or orange berries is usually seen against a wall. This prickly plant is commonly called Firethorn and if you have had a go at pruning one you will know why. But apart from those you rarely see wall shrubs any more.

What is a wall shrub? It is basically a woody plant that can be grown as a free standing shrub but in this case it has been planted near a wall and shaped and trained to create a vertical flat plant. They were very popular in the past but people generally look to climbers now when they think of wall coverings. Climbing plants are great but they can become somewhat unruly working their way up drain pipes and cables on the outside of houses.

This can become a maintenance problem when left uncontrolled.

Also, and I don't want to give you nightmares, but I have seen rats up around windows having found their way there via over grown climbing plants. I think they are looking for birds nests and maybe snails. I know this from personal experience and be sure I now maintain my climbers well away from any house access point.

Nearly all shrubs and trees can be wall trained if you are prepared to put a little effort into managing them early on and create a strong network of lateral branches. They will be slower than climbers but once established they are actually easier to maintain and won't get out of control.

Fruit trees have been grown against walls for centuries so why not grow Laburnum, flowering cherries or Acacia dealbata [Mimosa] as wall plants rather than as trees when space is tight.

Why grow wall shrubs? There are quite a few reasons actually. In small gardens it can be a very useful way to grow plants that you just wouldn't have room for otherwise. Take Ceanothus [Californian Lilac] for example. Much prized for its powdery blue spring and summer flowers it would make too big a plant for a town garden but lends itself as a great specimen to train on a sunny wall.

Ribes [Flowering currant], Viburnum, Forsythia and the beautiful Osmanthus delavayi also fall into this category along with nearly every other large shrub. .

Wall training is a great way to successfully grow tender shrubs that would be too exposed if planted free standing in a border to do well. A wall will provide quite a few degrees of frost cover. There are some lovely plants that fall into the category for warm sunny wall planting and not only do they have a better chance of thriving there they will flower better as the wood will ripen to provide flower buds in the additional heat.

Abutilon vitifolium 'Album' with three inch white saucer shaped flowers or the cultivar A. 'Veronica Tennant' the same only in mauve are truly stunning plants.

Sophora microphylla 'Sun King' with yellow flower from late winter to spring with delicate evergreen ferny foliage or Sophora tetraptera with larger flowers in May.

Chimonanthus praecox [Winter sweet] as it suggests produces very fragrant winter flowers. It really needs the backing of a south facing wall to produce good flowering wood but when it does you won't be disappointed. Coronilla glauca 'Variegata' is another pretty little plant that does so much better against a sunny wall producing yellow fragrant flowers from spring onwards.

My final reason for growing wall shrubs is that some plants just look better planted this way, and personally I include Camellias in that.

Other plants I think look better against a wall are Garrya eliptica' James Roof' [Tassle Bush] its long dangling catkins look much more dramatic when seen in linear form rather than on a rounded bush. This plant will do well on a north wall which is a bonus.

Azara microphylus is a plant that is both tender and will also grow on a north wall, it is an elegant foliage plant producing a multitude of tiny evergreen leaves.

Chaenomeles [Quince] are much better as a wall shrub. They can be a little straggly otherwise. C. Crimson and Gold' flowering in March is a favourite with the hot flower colours rarely seen at that time of year.

Finally Magnolia x grandiflora. Plant on a large sunny wall and give this plant room to show of its 25cms fragrant creamy flowers in October.

Wexford People

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