Thursday 19 October 2017

A seasonal high with the reds and yellows of autumn

Gerry Daly

It has been a strange year of leaf colour and falling leaves. Some trees, mainly birch and some maples, began to colour up their leaves at the end of August, at least one month early, and many trees began to shed a proportion of the leaves quite early.

But lots of other trees showed no colouring at all, while others again had one branch with yellow and red leaves and the rest still green. When one branch is coloured, it shows that branch is pinched at its base by the expansion of its neighbouring branches and it is not as well able to pass sugars back to the roots, causing the leaves to colour up.

The variable summer weather was near-perfect for trees. Many across the country have revelled in the mixture of sunshine and showers from June to September.

Most trees grew very strongly all summer and many made a second burst of growth as early as July, while this normally does not happen, if it happens at all, until August, and even then not all trees make secondary growth.

At the end of September and early October, a spell of sunny dry weather was ideal for encouraging good leaf colouring.

While some trees are still green and others are bare, many trees have now shed some leaves and the fall has gathered pace. These leaves are a valuable resource for the trees or bushes that shed them and they should be left in position under trees where they can rot down and release the nutrients they contain, while helping to retain soil moisture.

The leaves also help to suppress weeds under trees by excluding light and by releasing plant toxins.

This process is aimed at suppressing grasses, too, and if leaves are left on a lawn area, the grass can be killed or severely damaged.

On a dry day, collect leaves with the lawnmower and compost them with the grass. If the fall of leaves is too much for the lawnmower, the fallen leaves must by raked off, using a light leaf-rake.

These leaves can be composted separately to provide leaf-mould which can be used when potting up plants as a substitute for peat compost.

Wet fallen leaves can become dangerously slippery on paths and paved areas, and should be swept up before they begin to rot. Rotted leaves can release brown tannins that can stain paving badly.

"A few years back I purchased two blackcurrant trees and planted them alongside an apple and pear tree. However, the two blackcurrant bushes have escalated in size and are smothering the apple and pear trees. I want to relocate the two blackcurrant bushes elsewhere but firstly I want to know should I prune them before relocating them and what is the best time of the year to do this? There are still green leaves on the bushes but the fruit is gone. Your thoughts on this, please?" D O'Donnell, Co Waterford

If the bushes are of a size to be lifted without too much trouble, they can be lifted and replanted when the leaves have fallen. They could have some branches pruned out to make the process easier. Or you could simply take a few cuttings, about 40cm long, in November and insert them in the new positions, which must be weed-free. The cuttings route is easier but the plants are starting from scratch and fruiting will take longer.

Send your questions to gerrydaly@independent.ie. Questions can only be answered on this page.

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