Do You Dare to Try the “Chelsea Chop”?

In late May, many of us look forward to seeing social media posts about the Chelsea Flower Show. The timing of this event is a reminder that there are many perennials that benefit from a late spring cutback, commonly known as the “Chelsea chop.” Many perennials that bloom in midsummer, late summer, or fall can be pinched or cut back early in the season to increase flower production, limit plant size, extend or delay bloom time, create novel flower combinations, and minimize flopping or lodging. While the chop is generally timed to coincide with the famous flower show, it’s more important to time the trimming for a point when a significant amount of vegetative growth has occurred. For the Mid-Atlantic region, this can be any time from midspring to early summer.

A few of the herbaceous perennials that can benefit from having one-third to one-half of the vegetative growth cut back in late spring to early summer include:

As most plants grow, the tallest stems produce hormones that suppress dormant buds lower on the stem from growing, a phenomenon called apical dominance. When the top of the stem is removed, dormant buds at each remaining leaf axis are stimulated to produce multiple side shoots and an abundance of slightly smaller flowers. Because of the delay in the development of flower buds, you can expect flowers from side shoots to open two to three weeks later than the plant’s normal bloom time. This can result in unique combinations that would not normally be seen if the plants were allowed to grow unaltered.

An alternative technique that will extend a plant’s bloom period involves cutting back about half of the stems, distributed evenly throughout the plant. The uncut stems will bloom at the normal time, and the