In our climate it is best to plant in October, if at all possible. This allows the first autumn rains to soften the earth and then the plant has all winter to get its roots down and established.
Leaving it until spring means that the summer heat arrives too soon and no amount of watering can keep the plant alive - indeed soggy, warm conditions may cause fungal disease which will also kill the plant.
The best plants to buy - if you can find them - are small specimens in square pots. There should be a far greater proportion of roots relative to top growth if the plant is to get a quick start in life.
First soak the pot in a bucket of water - wait until any air bubbles are expelled.
The square pot encourages the roots to grow straight downwards which makes it more likely they will seek - and find - moisture in the ground. A round pot tends to cause the roots to wind around in a circle and eventually make a matted ball: this restricts the ability to take up water from the soil.
If you examine the root ball of a plant that has died you will probably find the roots curled up and constrained in this way. If you have to use round-potted plants then try for small specimens and tease out the root ball apart when you go to plant it.
When planting, even if there has been rain, the soil at depth may still be dry. It can be helpful when digging the planting hole to fill it with water and let it soak away before putting in the plant.
Put the plant in and back-fill with soil leaving a depression around the stem. This ‘saucer’ is very useful when watering as it ensures that all the water goes onto the plant and down to the roots rather than running off. Do not add fertiliser as we want the plant to grow slowly and establish itself with roots seeking nutrients deep in the soil.
Water in the plant with copious quantities both on first planting and then at intervals if it doesn’t rain. It should not be necessary to water more frequently than once a fortnight if you give a generous amount each time – even in the first year. In fact a plant treated correctly should be able to survive without irrigation by the second year.
Watering ‘little and often’ will just encourage the roots to stay near the surface and the plant will be weak and needy. A small shrub needs to be given around 5 litres at a time and a tree much more than that.
The photo at the top of this page shows a Cistus salvifolius ‘Bonifacio’ supplied by Olivier Filippi
Many of these articles first appeared in the Castiglione del Lago monthly newsletter “Qua e là” edited by Priscilla Worsley
All text and photographs © Yvonne Barton unless stated otherwise