GOLD stars!
Nothing puts on a spellbinding autumn spectacle quite like Japanese maples
THERE is no shortage of plants with fantastic autumn foliage, but none as spectacular as Japanese maples. As the weather starts to cool in October and November, their regular leaves turn fiery shades of scarlet, yellow and orange before dropping and forming a colourful carpet beneath its canopy of bare branches.
Many people are happy to travel long distances to see a collection of these wonderful small trees and large shrubs in full flight. Take my word for it, at this time of year it’s not unusual to find some gardens packed with thousands of visitors standing completely still in silence, spellbound by the spectacle.
Despite being justly famed for their autumnal exploits, Japanese maples are not just one-season wonders. Some have vibrant shoots that gleam brightly in winter, while their tiny spring flowers are followed by showy-winged seed pods. Many produce new foliage in March that changes colour as summer arrives.
The one downside with these plants is their cost. A young specimen in a 3-litre pot could set you back £25 to £40. My advice is to look on these long-lived gems as an investment, as those set in the ground or containers now will provide decades of enjoyment.
Japanese maples are native to Korea, China, Mongolia and, of course, Japan, where they flourish in moist woodland.
The first to be grown in Britain was Acer palmatum, which arrived in 1820, followed by Acer japonicum 44 years later. Acer shirasawanum put down roots at the tail end of the 19th Century.
Over the years, these wild species have provided plant-breeders with the genetic material to create hundreds of named varieties. These differ enormously in shape and size, from pendulous, mound-forming shrubs to upright, small trees. Their leaves are either lobed or finely dissected, and come in several different shades.
These arboreal treasures prefer fertile, consistently moist, welldrained soil in partial shade, but have the ability to cope with other types of soil, apart from those that are very dry or overly wet. They’ll sulk in ground that’s extremely alkaline and perform best in slightly acidic soil that contains plenty of organic matter. Smaller, hummock-forming types are ideal at the front of borders or set in rock gardens, while taller ones make the perfect centrepiece for mixed displays in beds or grown as standalone specimens in a lawn. Those with a natural weeping habit are excellent at the edge of a pond.
Planting container-grown Japanese maples is easy. Dig a round hole that’s about twice the diameter of the container and the same depth, then spike the sides and bottom with a garden fork to allow roots to penetrate. Scattering mycorrhizal fungi powder across the base will help trees establish more readily.
Scrape off the top layer of compost from the rootball to remove any weeds or moss, then tease out roots from the sides and bottom to help them grow into the surrounding soil. Place the tree in the centre of the hole and gradually fill the gaps with soil, firming it down as you go to remove air pockets.
Another option is to set really slow-growing or compact forms in attractive containers filled with a 50/50 mix of ericaceous compost and soil-based John Innes No3. They are perfect in terracotta, stone or Oriental-style pots that measure 12in to 18in wide, depending on the size of plant you start off with. Swathe containers in bubble wrap in late autumn to protect roots from frosts and stand them on bricks (or similar) to allow excess water to drain freely.
Every year, I receive a lot of queries from readers asking why the leaves of their pot-grown Japanese maples have mysteriously started to shrivel. The damage is a result of leaf scorch, a physiological condition that can be caused by the plant being subjected to frost, drought, wind or very hot sun.
To avoid this, display containers in light shade, in a sheltered position that provides some protection from cold or drying gusts.
In terms of pruning, these plants need very little attention. In fact, it’s best not to trim at all, but in late winter or early spring, remove any dead or damaged shoots, along with any crossing branches that are rubbing against each other.