Forsythia

Forsythia: how do you recognise it?

Habit

Upright to arching shrub of 2–3 m, with many stems from the base.

Leaf

Opposite, lance-shaped, 5–10 cm, toothed; sometimes trifoliate.

Bark

Yellowish-brown with lenticels; twigs hollow or chambered.

Flower

Bright yellow, bell-shaped flowers along the bare branches, March–April, before the leaves.

Fruit

Small capsules (rarely).

Difference from cornelian cherry

Cornelian cherry flowers even earlier, with much smaller flowers in little clusters.

Flowering: March–April · Pruning: April–May

Identify by feature: Yellow flowers in spring

Looks like it, but isn’t

• Cornelian cherry Cornus mas: much smaller flowers in little clusters. Difference from cornelian cherry

Why grow it?

• The brightest yellow flowers of early spring, on bare branches.
• Tough and easy: grows in almost any soil, in sun or partial shade.
• After flowering, a dense, fresh green shrub for a border or informal hedge.
• Easy to propagate: a branch that touches the ground often roots by itself.

Forsythia: where does it grow best?

• Sun to partial shade; it flowers best in the sun.
• Almost any garden soil, ideally neither too dry nor waterlogged.
• Allow 2–3 m height and 2.5 m width: give it room to grow into its natural shape.
• Lovely at the back of a border, as an informal flowering hedge or as an eye-catcher by the front door.

Light

Sun or partial shade

Legal basis

Any garden soil

Moisture

Normal

Size

3 m tall, 2.5 m wide

Hardiness

Throughout Belgium, no protection needed

Goes well with

• Cornelian cherry: Flowers yellow even earlier and does give bees nectar and pollen.
• Goat willow: Its catkins in March are a top food source for bees, at the same time as the forsythia.
• Flowering currant: Pink clusters in April that bumblebees and bees do visit.
• Grape hyacinths: Blue beneath the yellow, and early nectar for bees.

Good and bad companions

Goes well with

• Suits the woodland edge or the light shade of: ginkgo, box elder, ash, honey locust, field maple, silver maple

Forsythia: when and how to plant it?

1. Plant from November to March, bare-root or root-balled; container plants can go in later, except during frost or drought.
2. Dig a wide planting hole and mix some compost into the soil.
3. For an informal hedge: about one plant per metre.
4. Water generously after planting, and during dry spells in the first year.

Care

Watering

In dry spells during the first year; rarely needed after that.

Feeding

A little compost in spring is enough.

Mulching

A layer of leaves or compost around the base keeps the soil moist.

Rooting branches

Branches that touch the ground root easily: cut them off if you don’t want new shrubs.

Tip: To keep it smaller, remove more old stems at the base each year instead of trimming the tips: it stays graceful and flowers freely.

Forsythia: when to prune it?

Pruning months: April–May.

When: Straight after flowering (April–May).

How:

• Every year, saw a few of the oldest, darkest stems off at the base; the young stems carry the most flowers.
• If needed, cut flowered stems back to a strong young side shoot, so the shrub keeps its loose shape.
• A neglected shrub can be cut right back to 30 cm after flowering; it will regrow, but flower little the following year.

Caution: Don’t prune in winter and don’t clip it into a ball: you would cut off the flower buds.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Cuttings

In winter, push 20–30 cm lengths of one-year-old wood two-thirds into the ground, or take cuttings from young shoots in June; they root easily.

Layering

Bend a long branch down to the ground and cover it with soil; it often has roots within a year.

Forsythia: how does it get through the winter?

Hardy throughout Belgium: no protection needed.

• Fully hardy.
• The flower buds are formed as early as summer: prune in winter and you cut off the spring display.

Diseases and pests

• Few flowers: Usually caused by pruning in autumn or winter, or too much shade. From now on, prune straight after flowering.
• Bullfinches: In winter they sometimes eat the flower buds. There are usually enough left for a good display.
• Bare, woody shrub: After years without pruning, it only flowers at the top. For a few years in a row, remove a third of the oldest stems each time.

Through the year

• February: Flower buds swell; don’t prune yet.
• March: Flowering begins: yellow on the bare branches.
• April: Full flower; prune straight after flowering.
• May: Last pruning: remove old stems at the base.
• June: Take cuttings from young shoots.
• July: Next year’s flower buds are forming: no more pruning.
• November: Planting and hardwood cuttings.

What can you use it for?

Garden and landscape

The bright yellow herald of spring.

Caution: Of little value to bees; combine it with a cornelian cherry or willows.

Did you know?

• Despite the blaze of colour, it is of little use to bees: the flowers offer hardly any nectar or pollen.
• It is named after William Forsyth, an 18th-century Scottish gardener and one of the founders of the Royal Horticultural Society.
• Most garden forsythias are hybrids of species from China.
• The shrub is named after William Forsyth, a Scottish gardener and one of the founders of the Royal Horticultural Society in London.
• Most garden forsythias are not a wild species but a hybrid between two Chinese species: Forsythia × intermedia.