Acer

Acers are breathtakingly beautiful trees that few gardeners would do without.

A. palmatum ‘Bloodgood’ AGM - image: Floramedia
A. palmatum ‘Bloodgood’ AGM - image: Floramedia

In form, they range from large majestic trees to diminutive bonsai, offering a variety of foliage from classic five-lobed maple leaves to fine dissected leaves in many colours. In autumn, the maples really come into their own, turning shades of red and gold.

It is a large genus of more than 120 species of trees and shrubs found throughout northern temperate areas, with a large number in the Far East. Japanese maples, bred from A. japonicum and A. palmatum, are incredibly popular. Hundreds of cultivars have been bred from
A. palmatum, including ‘Bloodgood’ Award of Garden Merit (AGM), ‘Osakazuki’ AGM and ‘Sango-kaku’ AGM — ideal for smaller gardens and can be grown in containers.

But there are also the large parkland trees, including the Norway maple, A. platanoides AGM, with its popular varieties ‘Crimson King’ AGM and ‘Drummondii’. A. rubrum, the red maple, is another fabulous large tree — the cultivar ‘October Glory’ AGM produces a long-lasting display of brilliant red autumn colour. Two others widely seen in our countryside are the field maple (A. campestre AGM) and the sycamore (A. pseudoplatanus).

As well as offering incredible autumn colour, maples often have strikingly decorative bark. A. davidii and A. capillipes AGM are among those known as snakebark maples. The unique A. griseum AGM is known as the paperbark maple because of its cinnamon-coloured bark that curls back and peels off. It is a small, slow-growing tree that, although it can eventually reach 10m tall, is good for small to medium-sized gardens.

The huge variety of species, originating in regions of northern and central America, Europe, north Africa and Asia, means it is difficult to give generic cultivation advice. Japanese maples like a well-drained, fertile, loamy soil that is neutral to slightly acid. They can suffer from leaf scorch due to cold winds or hot sun so are best planted in a sheltered position. The red- and purple-leaved varieties need the sun to develop their richer shades. When grown in containers, they like a loamy compost. Feed in spring and early summer with a slow-release fertiliser or liquid feed and protect from temperatures below -5°C.

The larger trees prefer full sun or partial shade in moisture-retentive, well-drained soil. Despite perceived opinion that maples must be grown on acid soils, some (A. campestre AGM, A. griseum AGM and A. platanoides AGM) can be grown on chalky soils. Others, including A. rubrum, prefer lime-free soils.

Maples are prone to bleeding sap when cut so pruning needs to be carried out at the correct time, but this varies by type. Japanese maples should be pruned after leaf fall but before January. The snakebark maples, however, are best pruned in late summer. Only light pruning is usually necessary because they are quite neat in habit, even the larger trees, where the main concern is cutting out reverted growth in variegated forms. Small trees usually only need deadwood and badly placed growth removed.


What the specialists say

Karan Junker, co-owner, PMA Plant Specialities, Somerset

"Acer is huge genus so it’s important to choose the right species and cultivar. Their main feature is autumn colour, but the Japanese maples particularly provide enormous diversity of spring and summer colour as well as being wonderfully architectural. Those in the snakebark group also have dramatic stripy bark in winter.

"I have a lot of favourites, depending on what job you need it to do. I love A. rubrum ‘Sun Valley’ for when you need a big tree. ‘White Tigress’ is my favourite snakebark and I have way too many favourite Japanese maples to name here.

"There are a lot of myths concerning the requirements of Japanese maples. Contrary to popular opinion, they do not need acid soil and a lot of them will be fantastic in an open sunny site, provided the soil is suitable. They need soil of good structure that holds moisture well in summer but drains adequately in winter. They dislike extremes. They will tolerate sun and exposure provided they have adequate moisture at the roots.

"We find that they establish better from a larger size. A more mature plant is more robust, has more energy reserve and more dormant buds. Thus if the first flush of growth in the spring should get frosted, they have the energy to sprout again. This is particularly relevant with the Japanese maples and snakebarks."
 
James Harris, owner, Mallet Court Nursery, Somerset

"The popularity of Japanese maples endures for many reasons. They have incredible foliage and autumn displays. They are also easy trees to grow, doing well in open ground but also in pots.

"My favourites include A. palmatum ‘Bloodgood’ AGM, which is one of the larger maples and has gorgeous red leaves in the summer. A. palmatum ‘Osakazuki’ AGM and A. palmatum ‘Sango-kaku’ AGM are also great varieties. I also like A. palmatum dissectum ‘Crimson Queen’ AGM, with its finely dissected red leaves in the summer.

"Japanese maples will grow in most free-draining soils — acid and alkaline — but they do not like wet feet. If planting in clay, you need to add plenty of organic matter and some grit. For pruning, we advise that you cut back the current year’s growth at the end of June — if you wish to cut back to the older wood, then at the end of August or start of September. Maples grow fast when they are young and may put out a long growth that needs pruning to keep the shape. Later they slow down and usually make their own shape.

"Some protection may be necessary from a cold wind to avoid the foliage scorching. Most maples can grow in full sun but look after the variegated ones. The one enemy of the maple is a late spring frost. Then throw a net curtain or some garden fleece over the young foliage."


In practice

Shelley Mosco, managing director, Green Graphite Landscape Design, London

"I’ve used maples in many different ways. I’ve specified A. campestre AGM as a tough hedgerow species in rural wildlife schemes; A. griseum AGM for specimen planting in medium-sized town gardens because of its peeling, bronzy bark as a winter feature and showy autumn foliage; and Japanese maples because they are beautiful and easy to maintain.

"A. palmatum ‘Bloodgood’ AGM is a favourite because of its purple/red-coloured leaves in the spring that turn brilliant red in the autumn. I also love A. palmatum ‘Sango-kaku’ AGM for its red stems and peach-coloured leaves in spring, turning golden in the winter.

"Both of these trees can be kept successfully in large containers and suit courtyard or Japanese-style gardens, where their form and colour can be appreciated. The only problem is they don’t like the drying spring winds — this burns the leaves and, dependant on the severity, they could be brown tipped for the remaining season. Protect them. Make sure that they have adequate water and surrounding humidity."


Species and varieties

A. campestre AGM (H4), or the field maple, is a European native. It is a medium-sized deciduous tree with a compact bushy crown. It bears leaves with five blunt lobes that turn yellow or red in autumn. The typical winged fruits are small and green. Height: 12m+. Spread: 4-8m.

A. cappadocicum ‘Aureum’ AGM (H4) is a broad-crowned, medium-sized deciduous tree, smaller than its parent. Its leaves are bright-yellow when they emerge in the spring,
turn green over summer and then back to yellow in the autumn. Height: 10-15m.

A. davidii is known as the snakebark maple because of its stunning vertically striped green-and-white bark. It also produces glossy, mid-green leaves that turn orange and yellow in the autumn. It makes an excellent specimen tree for a medium-sized garden. Height and spread: 15m.

A. griseum AGM (H4) is a stunning tree because of its bark, which is the colour of cinnamon and peels away naturally in thin layers, giving it its common name, the paperbark maple. It also bears trifoliate leaves that turn brilliant shades of orange and scarlet in autumn. Height and spread: 10m.

A. palmatum is the Japanese species from which hundreds of cultivars have been produced. The Japanese maples are small, deciduous trees that have a graceful habit, autumn colour and beautiful foliage that may be coloured or deeply dissected. They are perfect for smaller gardens and can be grown in large containers.

A. palmatum ‘Bloodgood’ AGM (H4) is an extremely popular cultivar grown because of its lovely lobed leaves, which are deep-purple in summer but turn scarlet in autumn. It is a vigorous variety of Japanese maple. Height and spread: 5m.

A. palmatum ‘Osakazuki’ AGM (H4) is considered to have one of the best autumn displays of the Japanese maples. Its large, seven-lobed, bright-green leaves turn brilliant scarlet in autumn and last for several weeks. Height and spread: 6m.

A. palmatum ‘Sango-kaku’ AGM (H4) is known as the coral bark maple because of its bright-red stems, which stand out beautifully in the winter months. When they are young, the leaves are green with pink colouring, turn a rich green in the summer and then canary yellow in the autumn, with orange highlights. A fantastic year-round-interest feature tree. Height 6m. Spread: 3m.

A. platanoides AGM (H4) is the Norway maple — a vigorous, large tree with the classic five-lobed maple leaf. They turn bright-yellow, orange or brown in autumn. Many cultivars have been selected for distinctive leaf shapes or colourations, such as the dark purple of ‘Crimson King’ AGM (H4) and ‘Schwedleri’ AGM (H4), the variegated leaves of ‘Drummondii’ and ‘Emerald Queen’, and the deeply divided, feathery leaves of ‘Dissectum’ and ‘Lorbergii’.

A. pseudoplatanus ‘Brilliantissimum’ AGM (H4) is a widely grown form of the sycamore. It is smaller than its parent, becoming a small deciduous tree with a rounded crown. Its leaves emerge in spring, bright pink, turn yellow-green then dark green, mottled with cream. Height and spread: 4-8m.

A. rubrum ‘October Glory’ AGM (H4) is a lovely form of the red maple. It has glossy dark-green leaves that turn a brilliant red or orange and yellow in the autumn. It is pyramid shaped when young, with smooth grey bark. Later it develops an oval crown. Tiny red flowers are produced in clusters. Height: 10-15m.

Thank you to Floramedia, which supplied the images for this article from its photo library
www.floramedia-picture-library.com


Have you registered with us yet?

Register now to enjoy more articles and free email bulletins

Sign up now
Already registered?
Sign in

Before commenting please read our rules for commenting on articles.

If you see a comment you find offensive, you can flag it as inappropriate. In the top right-hand corner of an individual comment, you will see 'flag as inappropriate'. Clicking this prompts us to review the comment. For further information see our rules for commenting on articles.

comments powered by Disqus

Read These Next

Tree planting guide - three basic rules

Tree planting guide - three basic rules

Choosing the right plant, correct planting procedure and best aftercare are the three basic rules for sucessful tree planting, Sally Drury explains.

Tree planting - what are the benefits of planting trees?

Tree planting - what are the benefits of planting trees?

Mitigating climate change, providing windbreaks and reducing the risk of soil erosion are some of the best reasons for planting trees, says Sally Drury.

Dierama

Dierama

Beautiful but underused, this tall and elegant plant can persist for years, says Miranda Kimberley.


 
Horticulture Jobs
More Horticulture Jobs

Industry Data

An exclusive report for HW subscribers revealing the key development trends, clients and locations for 2017.

Are you a landscape supplier?

Horticulture Week Landscape Project Leads

If so, you should be receiving our new service for Horticulture Week subscribers delivering landscape project leads from live, approved, planning applications across the UK.

Landscape Contracts & Tenders

Products & Kit Resources

BALI National Landscape Awards 2016

Read all about the winning projects in the awards, run in association with Horticulture Week.

Noel Farrer

Founding partner of Farrer Huxley Associates Noel Farrer on landscape and green space
 

Read Noel Farrer