How to grow and care for forsythia

Grow forsythia in full sun or partial shade in garden borders. 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. If growing forsythia in pots, choose only the most compact varieties such as ‘Mikador’ and ‘Nimbus’, and plant into large pots with at least a 45cm diameter.

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 peat-free John Innes type of potting compost.

How to care for forsythia

Newly planted forsythias need watering during dry spells for the first year until established. Give a thorough watering two to three times a week, which encourages deep rooting. Forsythias growing in pots always need watering more often, especially from spring to late summer when growth is abundant, and plants take up more water.

In winter, forsythias in the ground need no special care, being hardy and robust. Pot-grown forsythias are more vulnerable as the root system is above ground, so move pots to a sheltered spot, such as against a wall, during spells of severe weather.

After pruning, mulch with well-rotted organic matter to keep the soil around the roots in good condition. Mulching is particularly beneficial on dry, free-draining soils where forsythias are more liable to dry out.

How to prune forsythia

Older forsythia plants 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. Compact varieties need little pruning.

Large, overgrown forsythias are commonly inherited when taking on a new garden, because this used to be a popular shrub to plant. Try to avoid cutting down the whole forsythia bush in one go, as this would result in a growth spurt of thin shoots. Instead, take out several 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.

Timing of forsythia pruning is important – prune immediately after flowering, 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 you will, unwittingly, be cutting off next year’s flowers.

How to propagate forsythia

Propagate forsythia by cuttings taken in mid to late summer, or by layering.

How to take forsythia cuttings

1. Select healthy shoots of the current year’s growth, which is just starting to become woody, and take cuttings around 10 cm long.
2. Prepare by using a sharp, clean knife to cut just below a leaf joint and removing the leaves on the lower two-thirds of the shoot.
3. Dip the base of the cutting in hormone rooting powder and insert in pots of seed compost mixed with a little perlite or sharp sand.
4. Cover with polythene or place in a propagator and keep under cover in a warm spot out of direct sun until new growth appears.
5. Grow on in good light until well established. Transplant into larger individual pots and grow outside for around a year until sufficiently large to plant out.

How to propagate forsythia by layering

If there are stems close enough to the ground to be pegged down into the soil, layering is an easy method of propagation that takes little work and doesn’t need any special equipment. Sometimes forsythias layer themselves without intervention so it’s worth inspecting around the base of the plant for any stems that have rooted themselves.

1. Select healthy low-growing stems and bend them down to touch the ground. At the point where the stem contacts the soil, use a sharp knife to remove a sliver of bark 1-2 cm long, which stimulates new root growth.
2. Peg down the stem to hold it securely in place, using a bent piece of wire or a stone. Cover this section of stem with good quality garden soil.
3. Simply leave for around a year for new roots to develop. Then, in autumn or spring, sever the rooted section from the parent plant and transplant to a new planting site, or pot up to grow on into a larger plant.

Growing forsythia: problem solving

Once established, forsythia is a trouble-free shrub to grow. If grown on free-draining soil that dries out quickly, forsythia bush leaves may shrivel during periods of dry weather, especially when hot. Remedy by an occasional thorough watering and a thick organic mulch over the root area to conserve soil moisture.

Pests and diseases

Forsythia is not liable to any specific pests or diseases.

Forsythia varieties to grow

Forsythias come in a range of ultimate plant sizes, depending on the variety, so choosing the right one to match your garden is important. The most compact ones, such as ‘Mikador’ and ‘Nimbus’, reach just a metre high and wide, and are suitable for growing in pots. The largest ones such as Forsythia x intermedia ‘Lynwood Variety’ and Forsythia x intermedia ‘Spectabilis’ grow to a height and spread of up to three metres. Forsythia x intermedia ‘Weekend’ is a medium-sized variety.

Frequently asked questions

Is forsythia evergreen?

Forsythia is a deciduous shrub which means it loses its leaves in autumn and produces new ones in spring.

What are the cons of forsythia?

While forsythia bush is robust, easy to grow, and blooms prolifically in spring, its season of interest is short, and the twiggy growth has little ornamental value for the rest of the year. Using forsythia as a host for a flowering climber such as a clematis, is a good way to create summer colour.