I have found restraint is wise both in the judgment of others as well as the pruning of forsythia. How harshly a plant is pruned may reveal something about the values of the person manning the shears. Or it might not. For example, one might believe tightly pruned forsythia to be a sign of a controlling or uptight personality.
Our gardens are often a reflection of our values, whether we intend it or not. Indeed, gardens throughout the centuries have tended to reflect the societal rules in place at the time. Still, when it comes to individuals, I choose to believe we do our best and maybe just need a little help along the way.
When it comes to the aesthetics of pruning, it often comes down to experience and knowledge. There are some plants that respond to pruning tightly (hedges, topiary, etc.) and other plants that look best when allowed to retain their natural shape. One thing is certain: If you bring electric clippers to the job instead of pruning shears, you have lost.
Forsythia is best, always, when allowed to grow with little or no pruning.
Prune gently or not at all and recognize that most plants look best when allowed to retain their normal shape, size, and growth habit. Deciduous plants especially are often not attractive when tightly pruned.
Notes about pruning forsythia
- In general, don’t. The more you can leave deciduous shrubs alone to reach their natural size and shape, the better.
- People will try to tell you to prune out crossing and weak branches. This is good counsel with many shrubs and trees especially, but truthfully I can’t be bothered when it comes to a stalwart like forsythia. More thoughts about (not) staying busy in the garden.
- Forsythia blooms on previous year’s wood. If you must prune, do so immediately after flowering. This will allow the plant to recover through the growing season, and most importantly, develop flowers for the following year.
- Other shrubs that should not be pruned tightly to hedges, topiaries, etc. are viburnum, most azaleas, hydrangeas, fothergilla. Almost all of the boxwoods are excellent, as well as yew. In the case of boxwood, they grow slowly so select a cultivar that reaches your desired size…waiting for an English boxwood to grow up requires patience and years.
Experience and knowledge combined with character and the will to act upon it = wisdom.
Other resources:
-Nice article from Horticulture Magazine about pruning forsythia.
-The always reliable Clemson University Cooperative Extension.
-Some words about how not to prune crape myrtle.