Autumn is the right time to buy and plant up trees and shrubs. Martyn Cox explains more in his new series for beginner gardeners.
If you’re at the start of your gardening journey, then you could be forgiven for thinking that autumn is the time when tools can be put away. Well, actually the opposite is true. Even though our gardens are sliding into dormancy, this is the perfect season for planting all sorts of things, including trees, shrubs and perennials.
Autumn has long been the planting season of choice for experienced gardeners. Being set into soil that is warm from summer but moist from rain, allows garden plants to establish readily as they require less watering than those planted at other times. Under ground, roots will form that enable plants to burst into life in spring.
How to plant container-grown specimens
Container-grown plants are freely available and can be planted at any time of the year. However, it’s best to avoid planting during drought conditions or if the ground is frozen or waterlogged. When selecting plants, check the firmness of the rootball in the pot by giving stems a little tug, ensuring they are container grown rather than recently potted up for sale.
To plant, dig circular holes that are three times the width of the rootball and the same depth. If the bottom of the hole is compacted, break the soil up lightly with a fork and prick the sides to allow roots to penetrate. Old gardening books recommend adding a layer of compost to the bottom of the hole, but this should be avoided as the tree can sink into the ground as the material rots.
Prior to planting, scrape off the top layer of compost from the rootball to remove any weeds or moss, and then carefully tease out roots from the sides and bottom to help them grow away into the surrounding soil. Place the tree in the centre of the hole and gradually fill with the excavated soil, firming it down as you go. Once the plant is in place, give the ground a good soaking.
How to succeed with bare root plants
Bare root trees and shrubs are one of the best-kept secrets in gardening. Available from November to March, dormant plants are lifted from the open ground and supplied as bare root plants, with no soil around their roots. Plants are sold individually or in bundles, and a key advantage over their container-grown counterparts is they are cheaper to buy.
Before planting, pop plants into a bucket of water for a few hours to ensure roots are hydrated. After they’ve soaked, check for any damage – trim away any branches or roots that are torn, damaged or diseased. If bad weather interrupts planting, dig a hole and plunge the plants into it, making sure roots are covered with soil. Alternatively, plunge them into a container of compost. Then you can gently dig them out and plant them later when conditions allow.
Bare root trees and shrubs need planting at the same depth as they were growing before being lifted for sale – look for a tell-tale ‘tide mark’ of soil on stems. Spread out the roots, and then dig a hole that is three times the diameter of the root system. Place the plant in the centre of the hole, then gradually fill with soil – gently bouncing it up and down to allow the soil to fall between the roots.
Unfortunately, bare root plants can lose up to 90% of their original root system when being lifted, so don’t expect too much in their first year – shoots are likely to be shorter and leaves smaller than normal. Growth will be better in year two and by the third year after planting, the root system will have almost recovered, resulting in vigorous growth.
Do I need to stake trees?
Small trees of about 1m (3ft) in height do not need staking, but any bigger and they will need some support. Use round or square tree stakes hammered into the ground vertically for bare root tree and stakes at 45-degree angle for container grown trees. Secure to the tree with plastic buckle ties. If it’s been planted properly, a tree will have anchored itself firmly after just 18-months and stakes should be removed to allow the tree to romp away without support.
Spread a 7.5cm (3in) layer of bark, leafmould or garden compost over the surface to lock in moisture and prevent weeds from growing. Keep the mulch clear of stems as contact can lead to bark softening and rotting. Strong winds over winter can cause tall, newly planted bare root specimens to rock backwards and forwards, creating a hole at ground level that makes an easy entry point for frost – check plants regularly and re-firm into the ground if necessary.