HOW TO CHOOSE A TREE FOR A SMALL GARDEN

At the nursery every tree fits in a small garden. The problem comes later, when the one that was two metres tall is eight, lifts the paving and blocks the sun from the neighbour's house. Almost every badly placed tree was chosen well and planted badly.

The three questions, in order

1. How big does it get? Not how big it is now. Look up its adult height and spread and draw it mentally in your garden. For an urban garden, a tree over six or seven metres is rarely a good idea.

2. What are its roots like? This is the one that really causes grief. Some species have aggressive, shallow roots that seek out water in pipes and lift slabs. Poplars, willows, figs and mulberries should not be near a house.

3. Deciduous or evergreen? In a small garden deciduous usually wins: it shades in summer and lets the sun through in winter, which is exactly when you want it. An evergreen in front of a south-facing window takes your light twelve months a year.

The distances nobody respects

As a minimum, and it is a minimum:

To the facade: half its adult crown diameter, and never less than three metres.
To the boundary: check local rules, but three metres for a tree and half a metre for a hedge is usual.
To pipes, wells or tanks: six metres, and more if the species is a thirsty one.

Species that do work

Lagerstroemia indica. Crape myrtle. Probably the best small tree there is for a Mediterranean climate: it flowers all summer when nothing else does, has beautiful bark, orange autumn colour and quiet roots. It stays at four or five metres.

Arbutus unedo. The strawberry tree. Evergreen, native, with flowers and red fruit at the same time in autumn, and it shrugs off drought. Slow growing and it takes clipping. There are compact varieties such as Compacta or Roselily if space is really tight.

Acer campestre. Field maple, the traditional hedgerow one. Yellow in autumn, discreet and very tough.

Acer ginnala and Acer monspessulanum. Two small maples, three to five metres. The first turns deep red in autumn; the second is purely Mediterranean and takes drought and limestone soil.

Acer palmatum. Japanese maple, for a sheltered corner with some shade. It is not a plant for full sun or dry wind, but in the right spot nothing matches it.

Beautiful species you should not plant there

And we say this even though we sell them.

Celtis australis, the hackberry, is one of the finest shade trees there is, but it passes twenty metres and its roots are powerful: it is a tree for a square, an avenue or a large plot.

Acer saccharinum grows fast and looks spectacular, but it gets enormous and has brittle wood that breaks in wind.

In a small garden they end up causing more trouble than pleasure. We would rather tell you now than in ten years.

And one more thing

Think about where you want the shade and at what time. Wanting shade at midday over a terrace is not the same as wanting it at six in the evening over the outdoor table. The sun moves, and a tree placed five metres to the left is no use at all.