Cut back perennials, native grasses as new growth is seen

  • As new growth starts to emerge, work begins to cut back perennials and clean up plant debris at Chicago Botanic Garden.

    As new growth starts to emerge, work begins to cut back perennials and clean up plant debris at Chicago Botanic Garden. Courtesy of Chicago Botanic Garden

By Tim Johnson
Chicago Botanic Garden
Updated 4/19/2019 6:48 AM

Finish cutting back perennials and cleaning up garden debris in the next couple of weeks. It is best to cut back perennials before they start growing to minimize any possible damage to the new growth.

It can be hard to see new growth on ornamental grasses, so be sure to cut them back before consistent warm weather sets in. If the weather warms up and the grasses are growing, then cut them at a few inches above the ground to avoid the new shoots.

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Be careful of any bulbs that have started growing. It is best to avoid or minimize walking on ground that is wet from melting snow, spring rains or as the frost is coming out. The soil will generally take longer to dry out during the cooler spring temperatures than it does in summer.

• Many evergreens are showing winter burn this spring after the long and difficult winter. Damage may continue to worsen as the weather warms up.

Your plants will likely recover if the damage is only on the exterior foliage. Some plants may be completely dead or beyond saving, while others will grow out this year. Yews tend to be resilient.

Look for new buds that are starting to grow -- this will be a good sign that your evergreen will recover. If a large percentage of the stems are dead and no new growth is starting, then you may have lost the plant.


Give the plants more time to begin growing, as it is still early in the season. The extent of the damage and how long you are willing to wait for the plant to recover factor into deciding whether to remove and replace the plant.

Prune out any brown sections once you can be sure the stems are dead.

• Begin uncovering hybrid roses in early April by carefully removing mulch from the base. A bamboo stake works well for this task.

Leave a small amount of mulch at the base for protection in case of a late hard freeze. Monitor the weather forecast and adjust your timing as needed, if extended cold periods are predicted.

Prune these roses back to live growth, which, in some years, may leave only 1 to 2 inches of stem. I have been seeing a lot of dieback on roses this spring.

• Tim Johnson is director of horticulture at Chicago Botanic Garden,

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