Forsythia Growing Guide

Forsythia x intermedia (Forsythia suspensa x F. viridissima)

Crop Rotation Group

Miscellaneous ●

Soil

Fertile, well drained soil with a neutral to slightly acidic pH.

Position

Full sun.

Frost tolerant

Yes, forsythia is a winter hardy woody shrub, tolerating cold to -15°F (-26°C).

Feeding

None generally needed.

Spacing

Single Plants: 6' 6" (2.00m) each way (minimum)
Rows: 6' 6" (2.00m) with 6' 6" (2.00m) row gap (minimum)

Sow and Plant

Forsythia is best started from a purchased plant set out in spring. Container-grown forsythias can be transplanted until early summer, but they will not bloom again until the following spring. Established plants are easy to propagate using the method known as layering. Bend a long branch until its tip is in contact with soil. Cover the stem with a bit of soil and a brick or other weight. After the stem develops roots, it can be dug up and planted elsewhere. Forsythias also can be propagated by rooting stem cuttings taken in spring, after the plants finish blooming. Forsythias need regular water for the first year or two after planting. Once they are established, water forsythias only during droughts. Check plant tags for the plant’s mature height and width, and adjust spacing accordingly. It is generally not recommended to grow forsythia in containers because even dwarf cultivars spread their branches and grow into very wide little shrubs. Young plants can be held in containers for a year if they are attentively watered, or they can be grown as outdoor bonsai.
Our Garden Planner can produce a personalised calendar of when to sow, plant and harvest for your area.

Notes

This popular spring-flowering shrub is adaptable and easy to grow in a wide range of climates. The plants shed their leaves in autumn, and bloom on bare wood in late winter or early spring. Because they bloom so early, blossoms may be damaged by late freezes. In cold climates, look for forsythia cultivars with good bud hardiness such as ‘Fiesta’ and ‘Meadowlark’. Proper pruning is essential to getting a heavy set of flowers. Forsythias bloom on year-old wood that starts growing as soon as flowering subsides. Pruning in late spring gives the plants plenty of time to set flowering buds for the following year. Prune large forsythias by cutting out the oldest branches near the ground. Avoid the temptation to shear forsythias into tight shapes. They look best when allowed to keep their long, arching branches.

Harvesting

In late winter, forsythia can be forced to bloom indoors. Smash the cut ends with a hammer to help them take up water, and place the stems in a tall vase, changing the water every other day.

Planting and Harvesting Calendar

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Pests which Affect Forsythia

Aphids (General)

Slug

Snail