Japanese maples (genus Acer) are a widely cultivated family of plants that are useful as small trees, large shrubs, container plants and bonsai. They were introduced to North America in the 1820s, more than 200 years after they were developed and bred by Japanese gardeners. Ranging in size from cascading dwarf shrubs to 9-metre (30-foot) tall trees, they enhance any garden or landscape with their wide variety of leaf shapes and colours.
How to Grow:
Though Japanese maples grow in sun or shade, in their native habitat they grow in the under storey of the forest in dappled sunlight and thrive when grown in similar conditions. In very bright sunlight or when summers are very hot new leaves may be damaged by sun burn. It is best to grow Japanese maples in a sheltered area away from strong winds where they get some afternoon shade.
Japanese maples grow in zones 5 to 9. Red varieties are more cold tolerant and obtain the best colour with at least 6 to 8 hours of sun. Those with deeply divided leaves need extra protection from the sun.
One light application of fertilizer in the spring is usually fine.
Japanese maples have shallow roots and do not like to dry out, so keep them moist throughout the year, particularly in the hotter late summer months. Groundcover plants or a surface mulch of stones or bark (keep away from the tree’s trunk) will help to conserve soil moisture. Avoid letting the soil get too soggy or the tree may develop root rot.
Japanese maples prefer a sandy loam, but will grow in most types of soil as long as it is well drained. They grow in a wide range of soil pH preferring a slightly acidic soil.
Major pruning should be done during the dormant season after the leaves have fallen, in late November to early January. Prune well before the sap starts running prior to the tree leafing out in the spring.
When to Grow
Japanese maples can be planted in the spring or fall.
Mulching trees late in the spring with a 7.5- to 10-cm (3- to 4-inch) layer of organic material helps to maintain evenly moist soil and insulates the tree’s roots. In areas where the winters are very cold, mulch again in the fall.
- Acer shirasawnum ‘Autumn Moon’ has handsome, rounded, many-lobed leaves of moonlight yellow and pink. The vigorous stems grow to 7.5 metres (25 feet).
- Acer palmatum ‘Peaches and Cream’ leafs out in spring with colours that its name suggests. Throughout the summer it displays colour variegation from green to pink. In fall it goes from gold to crimson.
- Acer palmatum ‘Shaina’ is an extremely slow growing variety with a rounded form. The disproportionately large leaves emerge bright red in the spring and become dark maroon red in summer. Then they turn a blend of oranges and reds in the fall.
- • Acer japonicum ‘Aconitifolium’ is a low-branched, small garden tree with deeply-cut leaves. Dark green in summer, the foliage turns a magnificent array of greens, yellows, oranges and reds as fall approaches.