Pruning: You asked us all about it so Peter Dowdall answered  

Gardening: Whether you're a beginner or expert, Irish Examiner columnist Peter Dowdall has the answer to your questions
Pruning: You asked us all about it so Peter Dowdall answered  

Hydrangea blooms have a beautiful winter-look in the garden and they act like a blanket to protect the plant from snow and frost but they will benefit from being pruned before the end of February. Picture: iStock

This lockdown passion for gardening is here to stay and everyone is out and about taking care of their outdoor patches. I have received dozens of queries to this page over the last month regarding pruning.

When to prune roses; Is it ok to prune apple trees now; when can I cut back hydrangeas? Let me attempt to answer these and other questions by offering some general advice.

Roses can be pruned now during the dormant period of the year. Realistically anytime between November and the end of February will do — though I do like to leave mine until February as there are often some blooms on them right through the winter months and I do enjoy them. However, the recent cold snap will have put paid to all but the most protected of blooms and so mine will face the chop this weekend.

In terms of how to prune, there are a few general guidelines that can be followed for many different types of shrub

In terms of how to prune, there are a few general guidelines that can be followed for many different types of shrub.

Irish Examiner gardening columnist Peter Dowdall. Picture: John Allen

Irish Examiner gardening columnist Peter Dowdall. Picture: John Allen

It’s important to create a good, open centre to the rose bush as this allows good air circulation which is important as many fungal infections which roses are prone to developing will thrive in areas with poor air circulation. If the centre of the bush gets too congested, then this not only leads to poor air circulation and ideal conditions for disease development but it will also lead to crossing branches rubbing off each other. 

This too should be avoided as when branches cross in the centre of a plant they inevitably rub off each other and create wounds on the bark which are ideal entry sites for infection.

So, when pruning roses, strive for a good open centre with no crossing branches. Do this by identifying three-five main stems and cut them back to between 20cm-40cm from ground level.

Try and prune to an outward-facing leaf bud as this will develop into a stem which will grow away from the centre of the plant which is what is wanted.

Just before bud-burst, that wonderful time of the year which occurs sometime in late March or April when the magic in the soil bursts out through seemingly dormant leaf buds to begin another growing year, drench the roses with a solution of copper sulphate and water.

This will help to prevent the development of any fungal infections during the growing season. 

This should only be done once per year and so it is important to apply at the most effective time of the year.

The same guidelines apply for apple and pear trees which can be pruned anytime before the spring growth starts though, I would recommend sooner rather than later. 

Again, you want to avoid crossing branches and to achieve a good open centre but with fruit trees, you are also pruning to maximise fruit production and so you also need to identify and promote the development of fruiting spurs.

These are swollen buds which look quite like dormant leaf buds but are more swollen and congested looking. It is these spurs that will produce fruits during summer and autumn and so you want to keep as many of these as possible.

Hydrangeas are one of the stars of the garden during late summer and autumn and I also quite like their winter look

Hydrangeas are one of the stars of the garden during late summer and autumn and I also quite like their winter look. The spent flowers which once were luxuriant in colour, now, a nearly transparent straw colour in the winter landscape.

I love the way these hold frost and ice and even the early dew in the morning. The main reason to leave these, otherwise dead flowers on the stems during winter is, not for winter aesthetics but rather to protect the plants from snow and frost during the winter months. They act like a blanket during this season.

Prune hydrangeas, again before the end of February. Maintaining a good open centre is nearly impossible with a mature specimen but do try and minimise crossing branches. If your hydrangea hasn’t had a good pruning in years then it will benefit from a restorative prune every so often.

Remove all older stems, some of which may be as thick as your arm and retain those of pencil thickness or slightly larger. Don’t do it all in one go as the shock may be too much for the plant but attempt to do about a third of the plant each year.

The remaining stems can them be cut back quite hard and to shape but there is one peculiarity. 

That is, if you prune a stem to below seven nodes or leaf buds then that stem will not flower this year. It won’t harm the plant but it will mean that you miss a year or two of flowers. Count the nodes/buds from the ground up and ensure that you leave at least seven on each stem.

Got a gardening question for Peter Dowdall? Email gardenquestions@examiner.ie

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