How to grow willow trees

Choosing a willow tree

Willows are often large, vigorous trees, suited to spacious gardens, but they come in various sizes so there also plenty of smaller options too. These robust trees can cope in most growing conditions, but really thrive in full sun and moist soil.

Choose the right willow tree for your garden:

Willow trees by size

Around 20 Salix species and cultivars have been awarded an RHS Award of Garden Merit, which shows they performed well in RHS trials, so are reliable choices.

To browse photos and descriptions of willow trees, go to RHS Find a Plant. You can also search by size, soil type, growing conditions and RHS Award of Garden Merit, to help narrow down your choices.

You may also be able to visit the UK National Willow Collection at Rothamstead Research (Harpenden in Hertfordshire), to see the wide range of species it grows. Its website even lists cultivars for basket-making!

Always check plant labels or cultivar

Gardeners often use the word variety when referring to a specific plant, but the correct botanical term is 'cultivar'. Whichever word you use, it means a distinctive plant or plants, given a specific cultivar name and usually bred to enhance certain characteristics, such as flower or fruit size, colour, flavour or fragrance, plant size, hardiness, disease resistance, etc. Additionally, it is worth knowing that, botanically, variety has another meaning - it refers to a naturally-occurring distinct plant that only has slight differences in its looks. For example, Malva alcea var. fastigiata differs from typical plants by having an upright habit.

descriptions before buying, to make sure you have enough space for the tree’s eventual size.

How and what to buy

Willow trees are widely available all year round in garden centres, nurseries and online by mail order. They are usually sold in containers and range from small saplings to large mature specimens.

Use RHS Find a Plant to find stockists of specific Salix species and cultivars.

How to choose healthy plants

Buying: trees and shrubs

When to plant

You can plant willow trees from autumn to early spring, whenever the ground is not frozen. However, autumn planting is recommended, because it allows them to establish their roots over the winter. They will need less watering than if planted at warmer times of the year.

Where to plant

• Choose a planting spot that is large enough for the eventual size of your tree, as many willow trees can grow rapidly to a substantial height and spread
• Plant in full sun, in soil that stays moist in summer
• Willows are tough and fully hardy, so can be planted in frost pockets or on particularly cold sites
• Avoid planting willow trees near building foundations or underground pipes, especially on shrinkable clay soil, as they have an extensive, vigorous root system that can take up a lot of water

Soil types

Trees near buildings

How to plant

Willow trees are easy to plant, and should be planted as soon as possible after buying – simply follow our planting guide below.

With willow trees in particular:

• Dig plenty of organic matter, such as garden compost, leafmould or well-rotted manure, into the planting area, to improve the soil’s ability to hold moisture
• Support trees that are more than 90cm (3ft) tall with a sturdy stake for the first few years, to prevent them rocking in strong winds or developing a lean

RHS guide to planting trees

Watering

• Water newly planted willow trees regularly for the first two or three summers, especially if the soil is not reliably moist during hot, dry spells
• To avoid unnecessary watering, check if the soil feels dry at a depth of about 15cm (6in), and if so, water generously, allowing it to soak in well
• Once well established, willows shouldn’t need watering when grown in the type of soil they prefer – moisture-retentive or wet soils, especially during summer

Collecting, storing and reusing water

Feeding and mulching

• Most willow trees are robust and vigorous and shouldn’t need feeding unless they are showing signs of nutrient deficiencies
• Mulching around the tree with well-rotted organic matter, such as garden compost or farmyard manure, is important to improve the soil’s ability to hold water and will provide nutrients
  

  To grow well, plants need a wide range of nutrients in various amounts, depending on the individual plant and its stage of growth. The three key nutrients usually taken up from the soil are nitrogen, phosphorus and potassium. Plants also need carbon, oxygen and hydrogen to make carbohydrates — their main energy source. Carbon and oxygen come from the air as carbon dioxide, while hydrogen is drawn from water absorbed by the roots. Other important soil nutrients include magnesium, calcium and sulphur. Most garden soils contain enough of these nutrients to support healthy plant growth.

  as it rots down
• Apply a 5cm (2in) thick layer of mulch
  

  Mulch is a layer of material, at least 5cm (2in) thick, applied to the soil surface in late autumn to late winter (Nov-Feb). It is used to provide frost protection, improve plant growth by adding nutrients or increasing organic matter content, reducing water loss from the soil, for decorative purposes and suppressing weeds. Examples include well-rotted garden compost and manure, chipped bark, gravel, grit and slate chippings.

  as the soil warms in early to mid-spring. It will help to deter weed germination
  

  Germination is the process by which a seed develops into a new plant. It starts with the seed coat absorbing water, expanding and splitting, which allows oxygen and water into the seed so its food reserves can be broken down and used by the embryo for growth. The first root (called the radicle) pushes into the soil to anchor the new plant in place and start absorbing water and nutrients. The first shoot (called the plumule) then grows upwards, out of the soil, towards the light.

  at the beginning of the growing season
  

  The period of time when an individual plant is in active growth. This will depend on the local climate and light levels, and can vary between different plants, although it is broadly from spring to autumn.

  too

How to feed plants

Nutrient deficiencies

Caring for older plants

Once your willow tree is growing away well, little maintenance is needed, other than to check it is getting enough water, especially in dry summers.

If the tree was staked at planting time, this can usually be removed after a few years, once the tree can stand unsupported without bending or shifting in the ground.

If the tree outgrows its space, it can be pruned or pollarded – see Pruning and Training, below.

Most willow trees benefit from some initial formative pruning after planting, to create a balanced framework of evenly spaced branches.

After that, they shouldn't need further pruning, unless you wish to encourage the production of colourful stems in spring, or to keep your tree smaller by pollarding or coppicing. See our guides below for full instructions.

Any pruning should be done from autumn to early spring, although you can still remove any dead growth at other times. Coppicing or pollarding should be done in April (mid-spring), just before new growth begins.

If any pruning is required on large trees, it is best to let experts carry this out. The Arboricultural Association website contains a directory of qualified tree surgeons.

Pruning for colourful stems or large foliage

Coppicing

Pollarding

Willows are easy to grow from hardwood cuttings

Hardwood cuttings are taken from mid-autumn until late winter from vigorous healthy shoots of the current year's growth - this will be woody but pliable. Use for deciduous climbers, shrubs, trees (including fruit) and some evergreens such as hollies.

, between November and February – see our guide below.

With willows in particular:

• Select healthy, woody stems from the current year’s growth, about pencil thickness and 20–30cm (8–12in) long
• Insert into deep containers filled with a 50:50 mix of peat-free multi-purpose compost
  

  Can refer to either home-made garden compost or seed/potting compost:

  
  • Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own.

  and coarse grit
• Keep in a coldframe or cool greenhouse over winter
• Check from time to time to make sure they haven’t dried out or are sitting in soggy compost
• New shoots will appear from the buds in spring
• They should be ready to plant out in autumn, and can be pruned (coppiced or pollarded) if necessary after two or three years

Cuttings: hardwood

Willows are usually robust, vigorous and healthy trees, if grown in a sunny position in soil that doesn't dry out. They don't grow well in chalky soil.

However, there are a few problems to look out for:

• willow anthracnose, scab and canker
• honey fungus
• tree rusts
• large willow bark aphids
• willow leaf beetles
• scale insects
• caterpillars and sawflies
• slugs and snails, which may damage soft, young, leafy growth

Managing pests and diseases without chemicals

Preventing pest and disease problems

If you’re a member of the RHS, you can use our online Gardening Advice Service, via MyRHS, for any questions or gardening problems.