At this time of year, a coterie of trees and shrubs begin to steal the limelight through a process of radical transformation, a metamorphosis of colour that ensures their elevation into the ranks of garden classics. I’ll always remember, for example, the first time I saw a Persian ironwood in all its fiery autumnal glory, its foliage a luminous blaze of crimson and gold. Ultra-resilient in the face of drought, waterlogged winter soils and even fierce cold snaps, a magnificent specimen of this large, deciduous, spreading shrub or tree greets visitors to the National Botanic Gardens in Glasnevin, where it grows just inside the main entrance. Suitable for bigger gardens, Persian ironwood’s autumn colour develops best when grown in full sun, but it will also grow in shade.
Famed for its elegant, palmate, finely lobed foliage and graceful growth habit, the large and very diverse species known as Acer palmatum or Japanese maple is equally prized by gardeners for its autumn colour. First introduced into cultivation in Europe in the early 1800s, the number of varieties now in cultivation is mind-bogglingly huge – as much as several thousand – and contains many that are garden worthy. But the variety most universally celebrated for its remarkable display of autumn colour is Acer palmatum ‘Osakazuki’, a bushy shrub or small tree whose leaves turn a brilliant shade of flame-red at this time of year.
Others Japanese acers that shine brightly in the autumn garden include Acer ‘Bloodgood’, a medium-sized upright tree with purple leaves that begin to flush bright red as winter approaches; and Acer ‘Sango-Kaku’, an outstandingly ornamental garden tree whose finely cut green foliage brightens to buttery shades of yellow and orange before they fall to reveal coral-pink young shoots.
For those of us with very small gardens, or with a soil not suitable for cultivating these lime-hating trees, container-growing is the way to go. Compact, slow-growing varieties of Japanese acer suitable for growing in a large tub or container and which offer a wonderful display of autumn colour include Acer palmatum ‘Garnet’; Acer palmatum ‘Dissectum’; Acer palmatum ‘Beni-Maiko’; and Acer palmatum ‘Orange Dream’. To keep them happy, make sure to give these containerised specimens a 50:50 mix of ericaceous compost and a loam-based John Innes compost, keep them regularly watered, and top-dress them in spring.
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Japanese acers growing in the ground need a deep, humus-rich, moisture-retentive but free-draining neutral-to-acidic soil to thrive, and are excellent candidates for a slightly shady, sheltered garden where their delicate foliage won’t be damaged by spring frosts, icy winds or intense summer sunlight, or by gales that might bring their autumnal displays to an untimely early end.
Yet another woody species that brings a joyful burst of brilliant foliage colour to the autumn garden is Ireland’s very own native spindle, Euonymus europaeus, a gorgeous edge-of-woodland or hedgerow species that’s also prized for its highly decorative, long-lasting, lipstick-pink and orange fruits. This grows wild in my own neck of the woods in rural Laois, lighting up the hedgerows at this time of year with its foliage in fiery shades of russet-red and crimson. Ultra-hardy and happy in either full sun or shade and a damp soil, the spindle bush also happily tolerates a lime-rich soil. While naturally bushy, it can be easily crown lifted to form a very decorative small tree. Cultivated forms are also available, including Euonymus ‘Red Cascade’, which has gently arching branches, while for something suitable for a small garden, seek out its colourful cousin, the winged spindle or Euonymus alatus.
For gardens where growing space isn’t an issue, the magnificent sweet gum tree, Liquidambar styraciflua, has traditionally been considered one of the arboreal glories of the autumn garden on account of its stupendous size, star-shaped leaves and eye-stopping display of brilliantly colourful autumnal foliage.
A native of the US, where its popularity is now in steep decline because its sticky, prickly fruits are such a hazard, in Ireland this tree does best in warmer parts of the country where its wood can properly ripen. While the fruits aren’t always reliably produced on most Irish sweet gum trees on account of our cooler summer temperatures, it’s worth noting that this may not be the case for very much longer because of climate change.
A very fine alternative – some would argue finer – is the katsura tree, Cercidiphyllum japonicum. This majestic, deciduous, lime-tolerant tree is famed for its graceful growth habit and extraordinary display of autumn foliage colour as well as the sweet, butterscotch scent of its heart-shaped leaves as they fall. In ideal conditions it can eventually grow as tall as a beech tree, but is very suitable for coppicing to keep it much more compact. Best in a deep, rich, moist soil with shelter from icy winds and harsh frosts, one of Europe’s largest specimens – a champion katsura tree probably planted in the late 1800s and last measured in 2021 at 22m x 5m – grows in the gardens of Ashbourne House in Glounthane, Co Cork.
This week in the garden
- Cooler temperatures and shorter days mean growing conditions in glasshouses and polytunnels are tricky to manage at this time of year, with fungal and bacterial diseases likely to be a problem. Reduce the risk by watering in the morning rather than at night, ensuring very good ventilation during the day, and removing any dead, decaying or damaged foliage/vegetables/fruits.
- Continue to plant most kinds of spring-flowering bulbs, the exception being tulips, which should be planted in November, when soil temperatures are lower, to reduce the risk of the very destructive fungal disease known as tulip fire (Botrytis tulipae).
Dates for your diary
Plant Collectors, Exploration & Empire, a guided tour at the National Botanic Gardens: Sunday, September 27th at 2pm, Glasnevin, Dublin 9. Part of Dublin Festival of History 2026, prebooking essential via Eventbrite.
How to Start A Fruit Garden: Sunday, October 4th (2pm-6.30pm) at the Tilled Earth Project, Tonragee, Mulranny, Co Mayo. A half-day practical workshop and study tour with organic gardener and author Klaus Laitenberger. €80 including supper, greenvegetableseeds.com
