Last week was national tree week when the Tree Council of Ireland promotes the planting of trees across the country.
Any regular reader of this column will know that I have a particular interest and love of trees and encourage their planting at all times. I've even gone as far as to suggest that in rural gardens, and there are plenty of those of half an acre in size or more, everyone should be made plant at least one large tree species.
By this I mean a long lived tree, at least 200 years, and a tree, that when mature, will be over 60 feet. Not only would this be good for the environment but it would have a beneficial long lasting impact on the beauty of our countryside.
If your an urban dweller there are still plenty of small tree options available. When planting trees in town gardens be aware of surrounding properties, a little consideration when selecting a tree type and appropriate planting spot can save conflict later. Most people like a bit of privacy but when that rare commodity of sunlight is cut out it can cause problems.
There's a lot of emphasis on planting native and naturalise species which is commendable but in a garden situation I feel foreign species are equally welcome. They actually add to the diversity of the tree stock grown in Ireland and helps soften the impact when diseases such as those affecting our elms and more recently ash populations strike.
So what constitutes a tree? Both trees and shrubs are woody and some shrubs can be quite large so this can be confusing. The general criteria for a tree to qualify as a tree is that it should have a clear stem of five feet and at which point it should be three inches in diameter. Above this it should have a discernible leafy crown to a height of at least fifteen feet. This should be clear but I still consider plants like the Japanese maples, Witch Hazels and some Magnolias to be small trees even though they don't fit all the criteria listed above. A moot point.
The reason March is always chosen as National Tree Week has a lot to do with the fact that we are coming to the end of the bareroot planting season. This was traditionally the way trees and hedging plants were purchased and planted. They are grown in the open field and lifted when dormant and sold as the name suggests with no soil on the roots. This method is by far the cheapest way to buy your plants. Bareroot plants really want to be in the soil by the end of March.
Not only are you limited in the species available as bare rooted plants but also your planting season is restricted. More and more growers are either root balling or container growing trees. Root balling is a term used to describe a tree that is still grown in the open ground but when lifted it is done carefully with soil still intact to the root system. This is then wrapped in sacking or plastic and sometimes chicken wire on large specimens. This method enables larger plants to be moved successfully and for some species, like Beech and large Birch, this lack of root disturbance is essential for successful transplanting. Root balled plants can be held over and planted until the end of May if necessary.
Container grown trees are grown in pots and can be planted at any time of year as long as they are kept watered. They tend to provide the most diverse and varied selection of species particularly useful for rare and unusual tree types that are not sold in large numbers. Another advantage is that a customer can see the tree in full leaf or flower when buying therefore now exactly what they are getting.
With it being Mothering Sunday this week why not give a present of a tree or plant one in memory. For a town garden I would recommend Mountain Ash, not too heavy in leaf but with plenty of all year interests. Look for varieties Sorbus villmorinii, S. cashmeriana, S. 'Joseph Rock' and S. 'Chinese Lace'. If you are really short of space a Japanese maple is ideal making some of the most elegant small trees available. Acer palmatum 'Seiryu' is an upright tree with feathery foliage. A. 'Sango-Kaku has beautiful coral coloured twigs. A. japonicum 'Aconitifolium' has lovely cut foliage.
Birch are always welcome in any garden large or small. Betula ermanii 'Holland' has lovely creamy pink bark. Betula nigra [ River Birch] is great for damp areas and has an incredibly shaggy peeling bark.
Cherries are unsurpassed as flowering trees. Prunus 'Amanogawa' is very upright and narrow. P. 'Tai Haku' has the largest white flowers. P. 'Ivensii' is a small weeping tree.
Large trees that are quick growing include Liriodendron tulipifera [Tulip Tree]. Quercus cerris [Turkey Oak] and Quercus frainetto [Hungarian Oak]. Acer platanoides [Norway Maple].
In the wet willows, alders and Pterocarya [Wingnut] all do well..