How to grow and care for forsythia
Advice on growing and caring for forsythia, in our Grow Guide.
Forsythia is an easy-to-grow, hardy deciduous shrub that makes a cheerful show of bright yellow flowers early in spring. Numerous small, bell-shaped blooms are borne along bare twiggy stems, before the mid-green leaves appear. Forsythias make excellent shrubs for garden borders but do have a relatively short period of interest, as neither the twiggy branches nor the large, toothed-edged light green leaves have any ornamental appeal, so avoid siting in a prominent position.
Forsythias are quick to grow and tolerate a wide range of growing conditions in the garden. Ultimate plant size varies considerably, depending on the variety – the most compact ones such as ‘Mikador’ and ‘Nimbus’ reach just a metre high and wide, while the largest ones such as ‘Lynwood’ grow to a height and spread of three metres, so choosing the right one to match your garden is important.
How to grow forsythia
Plant forsythia when plants are dormant from autumn to late winter, into well-prepared soil. Mulch and feed annually and prune immediately flowering has finished.
Where to grow forsythia
Grow forsythia in full sun or partial shade in garden borders. The most compact varieties are suitable for large pots. Forsythias thrive in a wide range of soils apart from waterlogged or extremely dry soil, although the best results are in soil that is fertile and well-drained.
How to plant forsythia
You can plant forsythia at any time of year but it's best to plant in autumn or winter, when the plants are dormant. Plant with the top of the root ball at the same depth as the soil level, firm in, and water well to settle the soil around the roots. For growing forsythia in containers, use a John Innes type of potting compost.
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How to care for forsythia
Once established, forsythia needs little care apart from pruning once flowering has finished. After pruning, mulch with well-rotted organic matter to keep the soil around the roots in good condition. An application of a general slow-release fertilizer at the same time will boost growth but is not essential.
How to prune forsythia
Older forsythia plants of larger-growing varieties benefit from annual pruning to encourage new growth and to keep larger plants within bounds. Trim back stems by around half and thin out any congested growth. Take out one or two of the largest branches every year, as near to the ground as possible. This lets light and air through the centre and encourages fresh new growth to develop. Compact-growing varieties of forsythia need little pruning.
When to prune forsythia is important: prune immediately flowering has finished, because next year’s blooms will be borne on growth made in the current year. If you prune later in the year or over winter and you will, unwittingly, be cutting off next year’s flowers.
How to propagate forsythia
Take half ripe cuttings in mid to late summer, choosing shoots of the current year’s growth which is just starting to become woody. Or propagate forsythia by layering, if there are stems close enough to the ground to be pegged down into the soil. This may occur naturally so it’s worth inspecting around the base of the plant for any stems that have rooted themselves.
Pests and diseases
Forsythia is usually a trouble-free shrub to grow.