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Trimming now will give flowers new blooms late in season

FROM THE GROUND UP | LINN COUNTY MASTER GARDENERS

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By Tina Patterson, Iowa State University Extension

I must be cruel, only to be kind: Thus bad begins and worse remains behind. Hamlet Act 3; Scene 4 William Shakespeare.

At this time of year you must learn to be cruel to be kind to some of your perennials. Cutting back healthy plants midsummer seems counterintuitive. Cut back that lovely growth? Cut away the flowers that are blooming? Yes and yes. Be brave and your garden will yield a refreshed look in a few weeks.

Most perennials will bloom for three to four weeks but some can bloom three to four months if you carefully cut them back and remove their seed heads. Flowers are meant to bloom and reproduce but if you cut them back, they start that cycle anew and reward you with fresh blossoms later in the summer and into the fall. These plants use up a lot of energy making flowers so when you cut them back, please feed them so they can focus energy on reblooming.

Many perennials respond to a good “haircut” by leafing out with a new vigorous growth and fresh blooms in the late summer. You can even manipulate their bloom time if you are planning to be gone on vacation during their peak performance days. Just prune them back and buy yourself a couple weeks more.

Plants that flower singly on long stems, like daylilies or hostas, need to have that spent stem removed deep within the crown of the plant. They may not rebloom. Yarrow, salvia, Gaillardia, Shasta daisy and other flowers that have leafy stems and flowers at the top will benefit from a simple brave shearing by about half. Other perennials are self seeders so dead heading or shearing will not be wise. Biennial foxglove, columbine, bleeding heart and Blackberry lily will set seed for next year. Removal of Cranesbill geranium, campanula bellflowers and Heartleaf brunnera foliage that is sun damaged or dry can allow them a rebirth of sorts. Keeping butterfly bush and scabiosa merely “deadheaded” will provide an abundance of healthy happy blooms. Moonbeam coreopsis is one that can be sheared back when seed heads outnumber buds and blossoms. It will pop back up in a few weeks.

During the Fourth of July weekend, I will be trimming back my leggy veronica and salvia that flop over or spread out, giving my weedy Cranesbill geranium a little off the top makeovers, and removing spent flowers from my Buddleia. Dry stems from bygone lilies and hostas will be removed. Catmint and Agastache will be trimmed back if blooms are finished.

A little aggressive snipping now may seem cruel but when your garden puts on another bright show of flowers, your trimming will seem kind and the worse will be behind. Thank you Mr. Shakespeare.

• For gardening questions, call the Linn County Extension Master Gardener Hortline at (319) 447-0647.

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