The magic of MAPLES
Wrap up and watch these trees put on a colourful show to rival any fireworks
IT SEEMS appropriate today (remember, remember, the fifth of November) to be writing about Japanese maples. Not because these compact trees have anything to do with Guy Fawkes and the Gunpowder Plot, but for the reason they usher in late autumn with a spectacular, fireworks-like display of colour.
As far as I’m concerned, the spectacle put on by these deciduous wonders is enough to rival any rocket, Catherine wheel or Roman candle – so wrap up warm, stand well back and you can gaze in awe as their leaves turn blazing shades of red, yellow and orange before eventually fizzling out.
The transformation is remarkable, and a result of various seasonal factors. Wet conditions in spring, followed by warm, sunny weather in summer encourages the build-up of sugars in leaves. Once photosynthesis stops in autumn, green tints will fade and these sugars produce fiery coloured pigments.
Anyone wanting to experience Japanese maples putting on a bravura performance should head to a garden with a great collection (Westonbirt, the National Arboretum in Gloucestershire has about 300 different ones), but if you want to enjoy your own private show in the future, snap up some container-grown specimens.
LATE autumn is the perfect time to plant these desirable trees – the soil is still warm from summer and damp from recent rain, allowing them to form roots that will promote vigorous growth in spring.
Next autumn they are likely to light up the garden from about mid-October until late November.
I should make it clear that Japanese maples provide all-year-round interest, too. Some have attractive spring flowers, winged seed pods in autumn or vibrant winter stems. The leaves of many are a fetching lobed shape, while ‘cut leaf’ types have finely dissected foliage.
These trees have been turning our heads since 1820, when a species known as Acer palmatum arrived from Japan. By the end of the 19th Century, it had been joined by A. shirasawanum and A. japonicum.
Over the years, this trio of wild species has provided the genetic material for plant breeders to create hundreds of named varieties. These vary from pendulous, mound-forming plants to upright, small trees. They are generally slow-growing (most will put on 1ft-2ft a year), so start with a large specimen if you’re impatient.
Before I go any further, a warning: not all Japanese maples have wonderful autumn foliage, so take care when buying. Those with green leaves tend to undergo the most dramatic transformation, while some with red or purple leaves don’t change. Yellow-leaved ones don’t colour up particularly well.
Japanese maples generally prefer a sheltered spot in dappled shade or partial sun (Bloodgood, Sangokaku and a few others can tolerate full sun), and perform best in slightly acidic, sandy, well-drained loamy soil that contains plenty of organic matter – they hate ground that’s very wet, bone dry or exceptionally alkaline.
Another option is to raise them in 12in to 18in-wide pots filled with a 50/50 mix of John Innes No2 compost and peat-free ericaceous compost, adding some controlled-release fertiliser granules. Protect roots over winter by wrapping the outside of the pot with bubble wrap and standing on pot feet to allow excess water to drain.
Larger varieties are excellent in lawns, mixed beds and borders, and set under taller trees. Really compact, mound-forming types work well in rock gardens, while those with cascading branches suit pondside planting schemes.
As far as problems are concerned, these trees are largely trouble-free. However, I often receive emails from readers asking why the leaves have shrivelled up. This is a condition called leaf scorch, caused by wind, sun or drought – avoid damage by settling the Japanese maple in the right place from the start.