Do Forsythia Spread by Underground Runners?

Underground Runners

• Many plants spread by specialized plant parts referred to as underground runners. These are similar in function to the above ground runners or stolons that are commonly seen in strawberry plants and the spider plant. Just like the above ground stolon, the underground runner also has nodes that start to develop into new plants and cause the parent plant to spread. Forsythia, however, does not have underground runners and the new plant stems arise from the base of the parent plant, causing the plant to increase in width.

Mature Size

• The plant is slightly weeping or erect in form, depending on cultivar, and grows to a mature height of up to 10 feet with a 15 feet spread. The 1- to 2-inches-wide, golden yellow flowers have four narrow petals growing from a thin tube. Each node develops up to three flowers. Foliage grows in opposite pairs. The 2- to 4-inches-long, toothed leaves have three lobes. The leaves often appear after the flowers have started to bloom in spring.

Pruning

• Pruning forsythias is a recommended maintenance practice that helps healthy plant growth. The best time to prune is immediately after flowering is over since the shrubs produce their blooms on previous year's wood. Waiting too long to prune will damage the buds and reduce blooming in the coming year. Remove the older, non-flowering stems entirely once every few years by cutting to ground level. This will encourage the plant to produce new stems.

Growth Conditions

• The shrub adapts well to a variety of well-drained soil types. Do not plant in poorly drained, wet ground. Choose an area in full sun for planting. Though the plant also grows well in shade, blooming is reduced in shade. The plants have few pest or disease related issues. Forsythias are commonly used in mixed shrub borders and grown as informal hedges. The dwarf cultivars serve as flowering groundcovers.