In the garden: When it comes to plants and trees should we stick with native species?

Planting native trees and shrubs in our gardens is good practice for providing habitats beneficial to our native flora and fauna.

A lot of trees and shrubs that we buy in garden centres are cultivated varieties, which means that they have been selected and bred to have particular characteristics which appeal to gardeners, like long flowering period, compact growth habit, attractive foliage, variegation, etc.

Many may be more ornate versions of natives like Sambucus nigra ‘Golden Tower’, which is a golden-leafed form of elder flower.

Many gardeners look for particular ‘garden-worthy’ qualities of plants so as to ensure that the garden looks good all year round.

Plants that have interesting qualities can also be good for wildlife, and gardens of any size make great refuges for fungi, bacteria, invertebrates, birds, and mammals.

We can all do our small bit to help support life on the planet, and one of the first steps is to stop the use of chemicals in supporting your garden.

The chemical revolution was seen as a fast and effective way of controlling pests and diseases, and the wider effects were initially not considered. It was a blanket cull of all creatures great and small.

Today, we have a broader perspective and look at the bigger picture and the future and sustainability of our gardening practices in an attempt to improve how we operate and to ensure a brighter future for all.

With changing weather patterns materialising, plants are starting to feel the effects of these changes and are suffering as a result. In Ireland, plant diseases are an ongoing part of an evolving ecosystem, with ash dieback the major news story in recent years. It is set to decimate our ash tree populations over the next few years, with the effects already evident in some parts of the country.

The symptoms of ash dieback include dead and blackened leaves among live foliage, wilting foliage, dieback of shoots and leaves visible in summer, and lesions or cankers on the main trunk or branches.

It is an airborne fungal disease, and therefore pretty impossible to control, as the spores are carried in the wind. At this stage, it is uncertain if it will infect all ash trees, some may have immunity and time will tell.

Dieback has shown very visible symptoms on a lot of trees nationally over the last 10-12 years, and it will result in a huge hole in the tree population of hedgerows as it freely spreads its airborne spores.

In the wake of changing weather patterns, pests and diseases, the question has to be asked about the possibility of introducing non-native species to ensure continued cover, in addition to supporting native flora and fauna.

Nobody wants extensive planting of a known invasive species like Rhododendron ponticum, which is known to colonise native woodlands as it aggressively self-seeds and layers, loving the Irish growing conditions, particularly along the west coast and mountainous areas of the country.

We need to be careful what we introduce, but is there room to promote the planting of non-natives that provide benefit to our natural ecosystems?

It does take some time to see how a species reproduces and responds to our ecosystems, and in places like Avondale Forest Park in Wicklow and JFK Arboretum in Wexford, there have been trials of different tree species from all around the world for many decades now.

It makes sense to attempt to future-proof planting trees and shrubs that can cope with different growing conditions in our temperate climate.

Ecosystems have always been evolving, the problem with the climate conditions that are materialising now is that changes are happening so rapidly that plants do not have time to adapt and evolve to cope with the droughts, flooding, high winds, rising sea levels, or whatever extreme they encounter.

Plants, like ourselves, thrive and grow best in a stress-free environment where they get plenty of food and water, stability and consistency, to establish roots, and grow strong and healthy with resistance to pest and diseases they encounter along the way.

The Tree Council of Ireland lists 33 native Irish tree and shrub species which arrived here of their own accord at the end of the last ice age about 12,000 years ago. These include familiar favourites like pedunculate and sessile oak, ash, hazel, willow and downy and silver birch.

In addition to native trees and shrubs, we have many naturalised species which have been introduced and enjoy our climatic conditions and so can freely self-seed and make themselves at home here.

Trees like beech, chestnut and larch are sometimes mistaken for native trees, having secured a place in our landscapes over the years.

Then there are invasives like Rhododendron ponticum, Japanese knotweed and sycamore that spread with wild abandon, to the detriment of our native plants and so need to be brought under control.

Careful consideration about what to plant this dormant season can be made so that the effect of the vegetation produced can be influential for the years to follow, in a positive way, supporting nature in our gardens and the broader landscape.

Happy planning and planting over the next few months!

Plant of the Week

Sambucus nigra ‘Golden Tower’, as mentioned previously, is a golden form of the ordinary elder flower.

When we plant our gardens, we look for qualities in a plant that make them interesting at different times of the year, and if they support biodiversity as well then it is a winner.

This shrub gets to about three metres in height with a one-metre spread and will benefit from being cut down to the base annually, producing fresh new foliage each year.

Its golden yellow foliage is eye-catching and it produces white umbels of flowers that pollinators will flock to in early summer. Best grown in a fertile, well-drained soil in full sun, or partial shade.