Learn how to grow acers and you'll be rewarded with vibrant, year-round colour and fabulous structure. With leaves in burnished shades of crimson, bronze and gold to vivid sherbet lemon and fuchsia pink, these showstoppers are surprisingly simple to grow.
When it comes to choosing an acer, there are three main things to think about. First, how big do you want your tree to grow? Some reach 4.5 metres while others stay around a metre tall, so factor in the size of your space. They come in two different shapes too, so do you want an upright tree, or a low-growing one? And finally, what colour and shape of leaf do you want?
To give you a hand with picking the best variety and helping it to flourish, we've gathered together plenty of top tips on growing acers below. And, if you're after an alternative, our best trees for small gardens guide has plenty more stunning options.
How to plant acers in the ground
1. Pick the best location. As well as ensuring your garden soil type is right (see below), acers also need shelter. Their delicate leaves can become scorched by cold winds and the sun, so choose a spot that has partial shade. Red-leaved varieties are more tolerant to the sun's glare.
2. Prepare the site by digging a hole large enough to accommodate your plant. Add feed and plenty of water to the hole.
3. When you're ready to plant, unwrap the root ball (it's best if the root is also damp, so soak it in water beforehand) and lift the plant into the new hole.
4. Before filling in the hole, check that the plant is upright and positioned exactly where you want it. Firm the plant into position, treading the soil down evenly around the root ball. Once well firmed, level the soil and water again.
How to plant an acer in a pot
Prefer the option of planting your acer in one of your garden planter ideas? The good news is they are one of the best trees to grow in pots and it's relatively straightforward with these step-by-step tips:
1. Use the largest pot you can find and add a layer of crocks (broken terracotta or similar) in the bottom to improve drainage. Put your container into position as it will be too heavy to move once the tree is planted.
2. Add a good layer of soil to the pot, forming a slight well in the centre, as acers prefer their roots to be quite shallow. Use a loam-based ericaceous compost, adding a scattering of sharp sand or grit to the mix.
3. If the compost around your new plant feels dry to the touch, immerse the plastic pot in a bucket of water to ensure it's refreshed before planting. Gently ease the tree out of the pot and loosen the roots so they're not compressed.
4. Position the tree in the well. Fill in the gaps around the roots with soil, pressing down as you go. Make sure the surface is level and the tree is well-anchored. The smoothed surface of the soil should be a couple of centimetres below the top of the pot. This means that the soil won't flood out when you water it.
5. Water the tree well, then keep it watered during any dry spells for the first year until it's fully established. Your acer will need repotting into a slightly bigger container every couple of years. Do this in April, and always use fresh potting compost to refill the container.
What you will need
This loam-based compost is our top choice for planting acers and is great value for money, costing under £12.
This round-headed acer produces purple-red blooms in spring, followed by red, winged fruits in summer, before it turns yellow, orange or red in autumn.
When should you plant an acer?
Growing acers from seed can be difficult and slow, so you might want to go for the easier option. You can buy young acers from your local garden centre and online that can go straight into the ground to give your garden an instant lift.
The best time to plant them is in autumn or early spring. This is because the weather is still cool (meaning the soil won't be too dry). Plus, it's much easier to dig a hole big enough when the ground isn't frozen.
How do you care for acers?
- Once planted in its spot, keep your acer's roots cool and moist but never waterlogged.
- Remember to water it during droughts, especially whilst the tree establishes itself.
- Feed every spring with a fertiliser that is meant for trees and shrubs (like this one from Amazon).
- Mulching over roots with well-rotted compost or soil conditioner is also key to helping them grow strong and healthy. Our ultimate guide to mulching has all the tips you need.
How do you look after acers in winter?
Winter can be harsh for all types of plants in our gardens – acers included. The single most important factor for keeping them protected and healthy during the coldest months is shelter. And, the more delicate the leaves of your tree, the more shelter it needs.
This means choosing a place that's protected from cold easterly and northerly winds and lingering late frosts, as these cause damage in spring after the delicate new foliage has emerged.
Putting a fleece (like this one from Amazon) over leaves if frost is forecasted will also help, as will providing shelter with overhanging trees, boundaries, walls or surrounding buildings.
If your acer is in a pot, protect it with a sheet of bubble wrap or fleece tied around with garden twine. Pot feet or bricks offer another level of protection by lifting the container clear from the ground.
What type of soil is best for acers?
When learning how to grow acers, it's worth bearing in mind that they favour moist but well-drained soil that is neutral to acidic.
If your garden only has alkaline soil, then it's easiest to plant your acer in a pot for the best results. Fill up your planters with ericaceous compost, allow for plenty of drainage (mixing grit into the soil can help) and keep them well-watered.
The purple-leaved 'Garnet' (available at Thomspon & Morgan) is a great choice for containers, as is 'Bi Ho' (available at Gardening Express) with its attractive winter stems.
Alternatively, look for acers that will tolerate higher pH soils – try snakebark and paperbark maples, for example, or the UK-native 'Campestre' (also at Gardening Express)which sports acid-yellow leaves in autumn.
Planting acers in heavy clay can also be problematic as they dislike waterlogged roots. If your garden has these conditions, be sure to incorporate plenty of organic matter into the hole at planting time, and avoid overwatering.
Problems to look out for
- Be sure to use the correct compost in order to ensure good growth. Fill your pots with a loam-based ericaceous compost – this will have the correct pH and won’t dry out as quickly as multi-purpose compost.
- Having too small a pot can cause problems if you're planning to grow your plant in a container as opposed to the ground. Potting your acer into a container twice as big as the pot it is supplied in will give the roots ample room to spread out.
- Keep on the lookout for vine weevil and treat it with biological control in late summer, watering the nematodes onto the compost.
Safe for children, pets and wildlife, these nematodes will kill vine weevils before they get to your acer tree.
Pruning acers
Acers require very little pruning, if any at all. Your tree will flourish and grow into an eye-catching shape if you let it develop naturally on its own.
As autumn comes to an end, you might need to give it a quick tidy up by snipping off any dead twigs. If you feel it's growing too tall or spreading further than you'd like, simply snip back any unwanted growth back to a side branch.
With a range of sizes on offer, acers are an ideal choice for many different gardens – whether you're working with a small patio or plot, or need to grow them in a pot. There's a great choice of leaf styles, too.
Found this helpful? Read our guide on how to plant bare root trees or discover the best evergreen trees to add year-round colour to your outdoor space.
The original version of this article previously appeared on Gardeningetc, a sister website to Homebuilding & Renovating.
