We all know that mature Elm trees are as rare as hen's teeth. Or are they? Dutch Elm disease is spread by the Elm bark beetle which likes to burrow into the bark of mature trees and eventually kills them. A burst of regrowth can live for 15 years or so, but then this will also die.
Elm trees were once the world's favourite urban tree and they lined streets from the Champs-Élysées in Paris to the Mardyke in Cork. Dutch Elm disease caused heartache everywhere it spread. Thousands of stately trees, many of them very ancient, had to be cut down.
But not all the Elm trees died. In fact quite a large number of mature field elms survive. Some of these are just isolated enough to have escaped the disease but experts believe others may have an inherent resistance. If this is the case these strains could be valuable into the future. A project with its base in the UK is aiming to reproduce surviving elms from cuttings. This involves taking cuttings from the surviving trees and growing these on for planting elsewhere. It's a long-term project and those who end up with the trees grown this way are asked to monitor them and report back to help with the study.
Because of the popularity of Elm trees, a number of strains of disease-resistant trees have been bred for the replacement of urban losses. Farmers looking for a something to do with odd corners of ground could help with the revival of elm trees by taking cuttings from local survivors, if they know of any, or by growing on disease resistant cultivars for re-sale to local councils for planting in parks etc. The elm is not dead, long live the elm!
For more on Elm cuttings, see: http://www.conservationfoundation.co.uk/project.php?id=2
The following advice on taking hardwood cuttings is courtesy of the Royal Horticultural Society. Hardwood cuttings are best taken in early or late winter, either just after the leaves fall or at this time of year, just prior to the sap rising.
- Select vigorous healthy shoots that have grown in the current year
- Remove the soft tip growth
- Cut into sections 15-30cm (6in-1ft) long, cutting cleanly above a bud at the top, with a sloping cut to shed water and as a reminder which end is the top
- Cut straight across at the base below a bud or pair of buds and dip the lower cut end in a hormone rooting powder (this promotes root formation, it also contains a fungicide, protects against rotting). Cut though the ‘heel’ where the shoot joins a branch for shrubs with pithy stems such as Sambucus(elder)
- Prepare a trench outdoors in a sheltered site with well-drained soil. Dig in a bucketful of garden compost or other organic matter every square metre or yard
- Insert the cuttings into the ground or pot with two-thirds of the cutting below the surface, with a layer of sand in the base. The roots will form along the stem. A few buds remain above the ground to allow the plant to grow away in spring. Where a single stemmed plant is aimed for, such as Populusor gooseberry, either leave only one bud above ground or rub off surplus buds
- Allow 10-15cm (4-6in) between cuttings and 40cm (16in) between trenches
- Check the trench after frosts and firm back if required
- Cuttings should be left in place until the following autumn ensuring that they do not dry out in dry periods in summer