Forsythia

Sun

Full sun gives the most flowers; tolerates partial shade but flowers less heavily.

Water

Water regularly during the first growing season. Once established, water during prolonged dry spells; avoid waterlogged ground.

Soil

Most well-drained soils, including clay that does not stay saturated; tolerates acidic, neutral and alkaline conditions.

Height

6-10 ft (1.8-3 m), depending on cultivar

Spread

6-12 ft (1.8-3.7 m), depending on cultivar

Flowers

Early to mid-spring; bright yellow, four-petalled flowers appear along the bare stems.

Foliage

Green, toothed leaves, usually oval to lance-shaped; autumn colour is variable, sometimes yellow or purplish.

Growth

Fast

Care needed

Low

• Water deeply when the root zone begins to dry during the first growing season.
• Apply a 2-3 in (5-8 cm) layer of organic mulch in spring, keeping it clear of the stem bases.
• On poor soil, apply a balanced shrub fertiliser in spring at the label rate; routine feeding is unnecessary on fertile soil.
• Remove unwanted rooted stem tips and suckers before they enlarge the clump.
• Leave space for the arching branches rather than keeping the shrub small by repeated clipping.

Pruning. Prune immediately after flowering, removing about one-quarter to one-third of the oldest stems at ground level and shortening flowered shoots where necessary. Avoid routine summer or winter clipping, which removes the following spring's flower buds.

Late winter

Cut a few budded branches to bring indoors for early flowers.

Spring

After flowering, remove the oldest stems at ground level and thin crowded growth.

Spring

Refresh the mulch and feed only if the soil is poor.

Summer

Water young plants during dry weather and remove unwanted rooted branch tips.

Early summer

Take softwood cuttings from healthy, non-flowering shoots.

Autumn

Plant while the soil is workable and moist, allowing for the shrub's mature spread.

• Plant as an informal boundary hedge where its arching stems can retain their natural shape.
• Use at the back of a mixed border, with later-flowering shrubs and perennials providing interest after the yellow flowers fade.
• Underplant with daffodils, grape hyacinths or hellebores for a layered spring display.
• Set against a dark evergreen background to make the yellow flowers stand out.

Garden styles it suits: English country, Traditional, Cottage garden, Farmhouse, Native hedgerow and Low-maintenance.

Plant it with: Daffodils, Grape hyacinths, Hellebores, Bergenias, Peonies and Hardy geraniums.

Wildlife: Dense branches provide shelter and possible nesting sites for birds. Flowers may receive insect visits, but forsythia is not a particularly valuable nectar or pollen plant.

• Few flowers: late pruning removes flower buds, while severe winter cold can kill them above the snow line. Prune only after flowering and choose a locally proven, flower-bud-hardy cultivar in colder areas.
• Sparse flowering in shade: move the shrub to a sunnier position or reduce overhead shade where practical.
• Leaf spots: remove badly affected fallen leaves, water at soil level and thin crowded stems to improve airflow; minor spotting rarely needs treatment.
• Woody stem galls: prune affected stems back into healthy wood, clean pruning tools between cuts and dispose of infected material; replace severely affected plants.

Not known to be toxic to cats, dogs, horses or people. No part is recognised as a significant poisoning hazard, but it is not a food plant and eating substantial amounts may cause digestive upset.

• Winter jasmine (Jasminum nudiflorum)

  Also bears yellow flowers on bare stems, but has green, slender stems and flowers usually with six petal lobes rather than forsythia's four.

• Witch hazel (Hamamelis species and hybrids)

  Its winter or early spring flowers have narrow, crinkled, ribbon-like petals rather than forsythia's broader bell-shaped flowers.

Forsythia honours Scottish horticulturist William Forsyth, while intermedia refers to this hybrid's intermediate characteristics between its parents, Forsythia suspensa and Forsythia viridissima.

Propagation. Take softwood cuttings in early summer or hardwood cuttings during dormancy. Layer a low branch into the soil and separate it once rooted; stems touching the ground may root without help. Propagate named cultivars vegetatively to keep their characteristics.

Accepted botanical name

Forsythia intermedia

Sources: GBIF (CC BY 4.0). The care and design notes are LandscapeGPT's own.