As gardeners prepare their outdoor spaces for winter, understanding the appropriate care for perennials and shrubs at the end of the growing season is essential for promoting plant health and encouraging robust blooms the following year.

Many perennials that produce seed heads should be left standing through the winter months. These plants provide vital food for nonmigratory birds and shelter for pollinators and other beneficial insects. Among the species recommended for retention are allium, aster, big-leaf lupine, black-eyed Susan, chocolate flower, coneflower, goldenrod, milkweed, rattlesnake master, sneezeweed, and trumpet vine.

Similarly, most shrubs that bloom in spring, such as azaleas, rhododendrons, forsythia, and hydrangeas, develop flowers on “old wood,” or branches from the previous year’s growth. Pruning these shrubs now risks removing emerging buds and should therefore be avoided. If pruning is necessary to maintain shape or size, it should be done no later than two weeks after the shrubs finish flowering in spring.

Ornamental grasses are best left upright during winter, as they not only create winter interest but also offer habitat for overwintering beneficial insects. Incorporating fallen leaves into garden beds further enhances shelter for these insects, which can help control pest populations in the coming growing season.

Woody or semi-woody perennials, like Russian sage and lavender, also benefit from being left standing. Their old growth helps protect the crown—the critical area where the stems meet the roots—from frost damage.

In contrast, certain plants should be cut back to reduce pest and disease risks. Hosta foliage, which can harbor slugs, should be cut to ground level after the growing season. Irises, known to harbor borer eggs that hatch in spring and damage plants, should also be trimmed back. Perennials prone to mildew—such as herbaceous peonies, bee balm, and phlox—should be cut down regardless of whether they showed symptoms during the year.

Gardeners should also remove any plants that were diseased during the season and clear away fallen leaves and debris from their beds to minimize infection risks for the following year. Annuals such as zinnias, commonly affected by powdery mildew, require similar treatment. It is advised not to add diseased plant material to compost bins; instead, dispose of them in the trash to prevent pathogen spread.

At any time of year, dead, broken, or diseased branches and shrub stems should be promptly removed to protect plant health and reduce hazards from winter storms.

Such attentive end-of-season garden maintenance supports not only plant vitality but also the ecological health of the garden environment.