How-to Guide
Growing and Pruning Forsythia
The short answer
Forsythia blooms on one-year-old wood and sets next year's flower buds in early to mid summer, so prune it immediately after flowering, within about two weeks of bloom. For routine upkeep, remove about one-third of the oldest branches every few years.
An overgrown or poorly blooming forsythia can be renewed by removing one-third of the oldest stems at ground level each year for three years, or rejuvenated all at once by cutting the whole shrub back to within 4 to 6 inches of the ground in late winter or early spring.
When to prune
Prune immediately after flowering, because forsythia forms next year's flower buds in early to mid summer on one-year-old wood. Pruning later removes those buds and sacrifices the spring display.
✔ For routine maintenance, take out about one-third of the oldest branches every few years within two weeks of flowering.
Renewal pruning over three years
- 1Year 1 — In late winter or early spring, remove one-third of the large, old stems at ground level.
- 2Year 2 — Prune out one-half of the remaining old stems.
- 3Year 3 — Remove the rest of the old stems, leaving vigorous younger growth.
Rejuvenation in one season
Old, neglected forsythias can be cut back to within 4 to 6 inches of the ground in late winter or early spring. They regrow quickly and usually bloom again within 1 or 2 years, but will not bloom the spring right after this hard cut.
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- University of Maine Extension — Pruning Forsythias (Bulletin 2513) — Prune within two weeks after flowering, buds form early-mid summer on one-year wood, remove one-third of old branches, three-year renewal method.
- Iowa State University Extension — When is the best time to prune forsythias? — Rejuvenate old forsythia by cutting to within 4-6 inches of the ground in late winter/early spring; regrows and blooms in 1-2 years.