Choosing and using plants. Small trees
The range of trees most suited to the smaller garden is extensive. While suitable when placed against existing, large trees, they can equally well be grouped to provide either a screen within your garden or to become a decorative element in themselves. The life span of the smaller tree tends to be shorter than that of the forest tree, but maturity is reached more quickly. Smaller trees grow naturally on higher ground, where wind and cold inhibits taller growth, and this is worth remembering when selecting species for roof garden planting.
The type of small tree you might use can be divided into two categories: those that are decorative and those that may be used to infill and build up your screen planting. But here personal taste is involved.
It is generally agreed that the genera Prunus (cherry and plum), Malus (crabapple) and Crataegus (thorn), will fit into the decorative list, since they all flower, fruit and have a degree of autumn colour. None, however, has any sculptural quality and you will look at a bare tree for half the year. Conifers, on the other hand, have their full shape the whole year round, but when used en masse provide a shape which is too demanding to fit most planting plans and too boring to view.
The smaller variety of silver birch or the thin weeping head of the willow-leaved pear (Pyrus salicifolia) are preferable substitutes to conifers.
More exotic, good value small trees are many of the maples (Acer sp.), admired not only for their leaves but for their branches and autumn colour. They are not grown for flower, but magnolias are and the adult tree has a good shape. The golden catalpa (Catalpa bignonioides), growing to 5m in height, is also spectacular when in flower, but it is most memorable for its huge heart-shaped leaves. The showering sprays of golden Genista aetnensis, and the midsummer gold of Koelreuteria paniculata followed by bronze bladder fruits, are also attractive. The golden robinia (Pseudoacacia frisia) develops into a pretty tree too. Amelanchier lamarckii, the snowy mespil, is a charming white-blossomed spring alternative to the cherry that has distinctive sculptural qualities.
For autumn colour you might consider Cercidiphyllum japonicum, the Katsura tree, for a lime-free soil. the leaves turn smoky pink, red or gold, and foliage is similar to the Judas tree (Cercis siliquastrum), which has purple, rose-type flowers in early May forming on its bare branches.
All these preferences have to be tempered with sound reason, however. Different locations at the same latitude might not support the same tree because of contrasted altitudes, for example. Climatic variations will also affect your choice of tree.
Using trees within a garden present a problem of scale unless you have acres of space. It is better to choose bold grouping if you can and to plant three or more of your chosen trees together. Parallel flowering can often be a problem, for in spring there is a flush of colour, then a gap, then early summer colour, and then another gap before the autumn crescendo. So try to choose your trees and plant them to provide a continuity of visual interest throughout the year.
The type of small tree you might use can be divided into two categories: those that are decorative and those that may be used to infill and build up your screen planting. But here personal taste is involved.
It is generally agreed that the genera Prunus (cherry and plum), Malus (crabapple) and Crataegus (thorn), will fit into the decorative list, since they all flower, fruit and have a degree of autumn colour. None, however, has any sculptural quality and you will look at a bare tree for half the year. Conifers, on the other hand, have their full shape the whole year round, but when used en masse provide a shape which is too demanding to fit most planting plans and too boring to view.
The smaller variety of silver birch or the thin weeping head of the willow-leaved pear (Pyrus salicifolia) are preferable substitutes to conifers.
More exotic, good value small trees are many of the maples (Acer sp.), admired not only for their leaves but for their branches and autumn colour. They are not grown for flower, but magnolias are and the adult tree has a good shape. The golden catalpa (Catalpa bignonioides), growing to 5m in height, is also spectacular when in flower, but it is most memorable for its huge heart-shaped leaves. The showering sprays of golden Genista aetnensis, and the midsummer gold of Koelreuteria paniculata followed by bronze bladder fruits, are also attractive. The golden robinia (Pseudoacacia frisia) develops into a pretty tree too. Amelanchier lamarckii, the snowy mespil, is a charming white-blossomed spring alternative to the cherry that has distinctive sculptural qualities.
For autumn colour you might consider Cercidiphyllum japonicum, the Katsura tree, for a lime-free soil. the leaves turn smoky pink, red or gold, and foliage is similar to the Judas tree (Cercis siliquastrum), which has purple, rose-type flowers in early May forming on its bare branches.
All these preferences have to be tempered with sound reason, however. Different locations at the same latitude might not support the same tree because of contrasted altitudes, for example. Climatic variations will also affect your choice of tree.
Using trees within a garden present a problem of scale unless you have acres of space. It is better to choose bold grouping if you can and to plant three or more of your chosen trees together. Parallel flowering can often be a problem, for in spring there is a flush of colour, then a gap, then early summer colour, and then another gap before the autumn crescendo. So try to choose your trees and plant them to provide a continuity of visual interest throughout the year.
