May 22, Prune forsythia plants right after they finish blooming in the spring. Wait for your yellow flowers to fade and for the leaves to grow. At this point, the plant starts to develop next year's buds, and the plant carries the buds through the fall and winter season. This 94%. Jan 03, Forsythia are vigorous shrubs that quickly bounce back from this type of rejuvenation pruning (provided that the shrub is healthy to start with).
Keep in mind that forsythia are large shrubs so even with rejuvenation pruning you’re likely to quickly end up back where you started; they can grow 8 feet stems in a single season!
Feb 11, Unless you are cutting a bush to the ground to start over, or you’re pruning a formal hedge, you don’t want to “gang” cut forsythia stems. Photo via Alamy. This is because cutting off the twiggy tips of the stems results in lots of weak, branching growth with few flowers, instead of the sturdy vertical main stems that bear the most blooms.
Jan 08, Pruning forsythia requires some basic knowledge of how the plant is meant to grow. Forsythia flowers give us one of the first splashes of color in early spring gardens. But to get that color and a well shaped shrub, it’s important to trim forsythia bushes correctly.
Prune these spring flowering shrubs soon after they have bloomed. Top prune the plant to improve the shape and reduce its size, but be careful not to remove more than 30% of the top growth. Some summer pruning can also be done on particularly vigorous plants, but not after mid-July. As the plant matures, some “renewal pruning” should be done.