In late spring, gardeners may heavily prune their perennials to delay blooms, tidy up their gardens, strengthen stems, and extend the flowering season. The more advanced version of “pinching back” your plants is called the Chelsea Chop. Why, you ask? The timing aligns with the Chelsea Flower Show hosted by the Royal Horticultural Society (RHS) in London in late May.
This type of pruning involves cutting an herbaceous plant back by about half of its height. It is best for summer-flowering and fall-blooming perennials. Some plants benefit greatly, but some perennials will be stunted if you Chelsea chop. Others may cease to bloom altogether until the following year.
Let’s discuss 15 perennials that will benefit from this special type of summer pruning.
1. Agastache Hyssop
A fragrant herb, anise hyssop attracts pollinators when grown near crops.
Although it’s not related to hyssop or anise, anise hyssop is a deliciously fragrant, pollinator-friendly perennial herb. I added a patch of it near one of our tomato high tunnels a few years back, and we’ve noticed a huge difference in the amount of bees and beneficial insects in the area.
Anise hyssop flowers and leaves smell earthy, like sweet licorice. The plants flower abundantly all summer. The two-lipped blooms feature long anthers, making it easy for pollinators to feed.
When plants are Chelsea chopped, you’ll have plenty of flowers to satisfy the bees and copious leaves to be dried and steeped into tea later. To prolong the blooms later into the fall or encourage a bushier, shorter plant, cut down a third of the height of the plant. This plant is fast-growing, so you may choose to cut the whole thing. Don’t worry, it will grow back full, strong, and healthy. Deadhead spent flowers throughout the season for continued blooming.
2. Asters
Chelsea chopping benefits aster plants, encouraging prolonged blooming and preventing the need to stake taller varieties.
There are many daisy-like flowers still referred to as ‘Asters,’ although they have been reclassified into different genera. With more specific genera, growers can find and grow the exact type of flower they’d like to. The genera include Aster, Callistephus (China aster), Eurybia (big-leaved aster), Kalimeris (Japanese aster), and Symphyotrichum (American aster). Any perennial aster benefits from the Chelsea chop.
Asters bloom well into the fall, but to keep them going even longer, chop half of your cluster to encourage the plant to produce side shoots. They may appear smaller in size, but they’ll be big in impact. This method also prevents the need to stake taller varieties such as ‘Violetta.’
3. Campanula
This plant benefits from heavy pruning in early summer to delay blooms.
This herbaceous perennial provides luscious white, blue, purple, pink, or blue-violet bell and star-shaped flowers, and they do best where summers are not extreme. Campanula offers the perfect hues for a cottage garden and also performs well in containers.
Perform the heavy pruning in early summer to delay the blooms by four to six weeks. Although chopping may cause blooms to be smaller in size, they’ll be more abundant.
Chop back only a little bit of the patch at a time to give you more of a staggered second bloom.
4. Nepeta
A resilient herb similar to catnip, catmint boasts colorful blooms that attract pollinators.
A close relative of catnip, catmint is a tough perennial herb with abundant pink, purple, or white spiky blooms. Their many florets are a huge source of food for pollinators.
Catmint’s resiliency to pests and diseases and its ability to deter critters with its strong scent make it an easy choice for low-growing perennial or sloped areas.
Catmint plants get unruly if left alone, especially in large patches, so Chelsea chopping is a great way to control it. Normal bloom time will be early summer, but when chopped in late spring, a bushier, more manageable plant develops, and blooms are delayed. Chop just half the patch for blooms practically all season!
5. Echinacea
A wild perennial found across central and southeastern U.S., echinacea serves as wildlife food.
This wild-looking perennial is found all over the central and southeastern U.S. in gardens, meadows, woodlands, and prairies. It tends to be a bit loose-petaled and is pale pink, vibrant purple, or magenta. The petals may arc downward even when plants are healthy, and leaves are deep green and large.
Echinacea is an important source of food for various wildlife. Its stems are tall and sturdy but only sometimes branch out.
Chelsea chopping encourages more blooms and creates lower-side shoots, causing plants to be sturdier and bulkier. Flowering typically begins in mid-summer and lasts up to four weeks. Chopping in early spring will delay the bloom. Prune down to the ground after they bloom for a possible second flush.
6. Foxglove
The foxglove’s stunning leopard-printed tubular blooms may fade early after rain.
Is there anything more stunning than the attractive pollinator “runway” of the tubular foxglove blooms? The internally leopard-printed flowers alternate on tall, strong stalks. However, they can peter out early, especially after lots of summer rain, and become unsightly.
Foxglove provides a showy, first big flush in early summer. This summer beauty comes in white, yellow, pink, red, and purple three-inch-long flowers.
Once pollinators are done with them, Chelsea chop the stems down to the ground. Foliage will continue to look attractive, and hopefully, you’ll get a second set of blooms that will be even sturdier and more upright than the first.
7. Hardy Geraniums
These are enduring perennial plants with diverse colors, thriving in various gardens.
While often confused with annual geraniums, hardy geraniums are true and long-lasting, low-maintenance perennials. The term “geranium” is often used interchangeably as they can all be grown as perennials in their native habitat. With lots of colors and shades to choose from, they’ll look great in just about any garden.
Some hardy geranium cultivars bloom all season long, each offering a unique spin on the five-petaled, saucer-shaped flower. To stagger the harvest, cut ⅓ of your patch down in late May and another ⅓ in early to mid-June.
8. Helenium
Sneezeweed blooms in late summer and can be pruned for compact growth.
Sneezeweed is an orangeish-red member of the aster family that typically blooms in late summer. It adds charm to a cottage garden and more abundance to a pollinator patch. It can be grown successfully in containers.
Full sun prevents sneezeweed from becoming leggy. In addition to proper sunlight, cutting them back creates a low-growing, bushy, and compact plant that looks great in mass, grouped in threes or fives with other late-season ornamentals.
By performing a Chelsea chop, you’ll delay this plant’s bloom cycle into fall or late fall, when other flowers have faded or gone to seed. Not only will they bring beauty to the garden, but they’ll also provide butterflies with much-needed food in the late season. Pair them with autumnal sunflowers and deep shades of mums for a fall centerpiece.
9. Shasta Daisy
The Shasta daisy offers enduring beauty in gardens with its white petals and yellow centers.
A cross between the oxeye, English, and Portuguese field daisy, the Shasta daisy brings pure white joy to gardens with its crisp white petals and bright yellow centers. Once established, it is drought-resistant, has few disease and pest issues, and is resistant to deer and rabbits; what more could you ask for?
Although she looks delicate, this herbaceous perennial is tough and easy to care for. Growth takes off with well-draining and composted soil in a sunny area, and she’ll return year after year. Divide plants every few years to maintain pure genes or allow them to self-seed for potentially different looks each year.
Depending on the variety you select and your growing zone, perform the chop once 10-20 inches of new growth has occurred. This gets you three to six additional weeks of blooms later in the season. If you’ve divided your daisies and have them in different areas of your garden, prune them by section so your garden will feature blooms all summer.
10. Pineleaf Penstemons
With evergreen needle-like leaves, pineleaf penstemons can be creatively planted in rock walls.
If you’re looking for a perennial that’s beautiful, easy to maintain, and complements every type of garden imaginable, beardtongues are it! The flowers are bold-colored and uniquely tubular. They face downward, similar to foxglove but much more slender.
Penstemons have evergreen, needle-like leaves and handle drought conditions very well. Plant them along rock walls for a unique look, or grow in containers and add them to a patio or walkway.
With a regular bloom time of early to midsummer, they’ll bloom for three to four weeks. To extend the season and shorten some of the taller varieties, cut them back in the spring to delay their blooms until late summer once early bloomers like peonies, irises, and daylilies have faded. If you have large clumps of beardtongues, chop around the edges and leave the center intact. The outer stems will branch out, creating support for the center blooms.
11. Garden Phlox
Flowering phlox is a dependable garden addition that benefits from deadheading.
It’s no wonder flowering phlox is widely added to perennial gardens. It’s very dependable and adds early spring and summer cheer with its white, pink, red, and purple flowers. Its bold colors and sweet scent attract many pollinators, and some cultivars can bloom for up to six weeks.
Performing the Chelsea chop causes this perennial to become a “garden backbone” because it develops a bushier growth habit and delays its blooms by four to six weeks. Try ‘Sunset Coral’ for a vibrant orange option.
Deadhead at the end of the season and remove seeds to keep next season’s plants looking the same as this year’s. Otherwise, seeds that sprout will likely feature a pale magenta flower. Divide your plants every few years to provide healthy airflow and reduce the risk of powdery mildew.
12. Rudbeckia
A versatile perennial, black-eyed Susans thrive in various soils and benefit from a specific pruning technique.
This cheerful black-centered, golden, daisy-like perennial is easy to establish and maintain. Black-eyed Susans adapt fairly easily, growing best in slightly moist soils of clay, loamy, or sandy consistencies.
Black-eyed Susans grow back with more branches after Chelsea chop pruning in late May. The side shoots create a much-needed base support to keep them from blowing over. This may remove the need for staking.
This perennial responds well to cutting the whole clump back by about ½ its height rather than selectively pruning only some of the clump since they can get so tall. However, if you’d like to have staggered blooms, cut the front third of your patch back by ½ its height, then the second (middle) third by ⅓ its height, leaving the back at full height.
13. Sedum
Adaptable perennials with diverse heights and colors, sedums benefit from a May pruning for more compact growth.
Sedum comes in both low-growing and tall options, with the tall ones responding well to the Chelsea chop. In terms of perennials, sedums are one of the easiest to grow and adapt to just about any growing conditions.
This juicy succulent looks lovely along a rock border wall or perennial pollinator or cutting gardens. Sedums have red, magenta, or pink flowers in tight clusters, forming larger flower heads. Seed pods left on plants are attractive during winter months but can be cut down in the fall if you prefer.
If your soil is overly rich, sedum may become leggy, but Chelsea chopping will help prevent legginess. Be sure the soil is well-draining to avoid root rot. Chopping plants in late spring will create more compact, shorter plants and may also encourage more flowers. ‘Autumn Joy’ and ‘Autumn Fire’ are easy choices.
14. Salvia
This low-maintenance, long-lasting flowering herb attracts pollinators with its deep purple blooms.
This woody, flowering herbaceous perennial is easy to grow and care for and will attract large amounts of pollinators to your garden. It blooms a gorgeous deep purple color and can last for many years with high resistance to drought.
Salvia is in the mint family, so its growth can be rapid and may become unruly, making the Chelsea chop a perfect way to keep it under control. Try ‘Crystal Blue’ or ‘Caradonna’ in cutting gardens.
Remove any dried-up or woody stems in the spring to encourage new growth. In late May or early June, perform the chop to established Salvia plants by trimming them ⅓ of the way back. The cuttings can be dipped in root-stimulating hormone and put in fresh soil to create new softwood cuttings.
15. Yarrow
By Chelsea chopping established yarrow in late spring, you can delay blooms, and strengthen stems.
Established yarrow is always one of the first things to pop up in the spring in my neck of the woods, and I’m always craving more of it by late summer. To extend the yarrow blooms, I Chelsea chop half the patch, delaying the blooms for a few weeks and providing me with this lush bouquet filler into the summer months.
Yarrow is quite hardy but can have weak stems that blow over in heavy wind or summer rain storms. Pruning with this method creates a bit of a bushier plant and stronger stems and may prevent you from having to stake them.
The extra airflow will be appreciated, too, and it may keep the base of the stems from browning as they often do after excessive rain or heat.
Final Thoughts
While the Chelsea Chop shouldn’t be performed on all plants, many herbaceous, flowering perennials respond very well. Have fun experimenting with this method of pruning for extended flowering, delayed blooms, and tidy gardens.
