An ongoing debate: Should it be downsized this fall or next spring?

Does anyone know where I can get perennial ferns? I’m asking for a ringworm.

Gardening has its own dialect, going far beyond terms like perennial and frond. For example, “slimming down” has nothing to do with reducing the calories we eat. In gardening terminology, cutting back means reducing the size of a plant.

When we hear discussions about pruning in the fall, it’s usually about whether to prune the tops of perennials. To decipher another gardening term, “tops” is not just the highest point, as in the top of a building, but “trimming the tops” of perennials means cutting off all above-ground stems and leaves to an inch or two above. Ground level.

By their nature, perennial flower stems die back to the ground each winter, and growth returns each spring from below the soil level. If dead tops are allowed to remain from year to year and are never removed, most perennials will become a tangled mess of new shoots trying to emerge from a thicket of dead leaves and stems.

For health, it’s best to cut perennials sometime between this fall and before growth begins next spring. But which is better, fall or spring?

Most perennials are best left intact over the winter rather than cutting them back in the fall for several reasons. For example, it is easier to locate perennials next spring if the stems are still there.

The perennial stems and seed pods provide winter habitat and food for birds and wildlife. Native pollinator bees create winter nests in the hollow stems of perennial flowers and ornamental grasses. Bees that overwinter in our perennial gardens will be on site and available to pollinate our strawberries, apples and cucumbers next spring.

Allowing perennial stems to stand over the winter helps catch leaves and snow and retain them for insulation and moisture. For some perennials, waiting until early spring to cut back greatly improves their winter survival.

The extra protection provided by roofs is especially important during cold winters with little snow and in windswept areas. Surfaces left intact also reduce the alternating freezing and thawing of the soil, which can lead to injury to perennial plants.

Perennial flowers add beauty to the winter landscape. Varied shades of brown with contrasting textures and shapes create interest in the white palette of falling snow. Ornamental grasses are at their best in the fall and winter, swaying in the breeze and creating movement with their unique leaves and seed heads.

When perennial tops are left intact over the winter, cut them back in the spring before new growth emerges from the soil level. Prune before new growth mixes with old, dead stems, making removal difficult.

Although there are good reasons to allow perennial leaves and stems to remain over the winter, some gardeners choose to clear and trim the entire perennial bed in the fall. This method can also be successful, although it increases the chances of something going wrong.

Although most perennials are best left intact, some should be pruned back in the fall. Peonies are susceptible to foliage diseases and blossom pests. After several periods of frost, the peony tops return to near the soil level and are disposed of in the garbage. If other perennials suffer from foliage blights, prune and dispose of them as well.

Hosta leaves become soft and difficult to remove if left until next spring. Around the time of the first frost, cut the hosta leaves to an inch or two above the soil level.

Chris Flynn/Forum

Iris leaves also become weak and difficult to handle by next spring, so it is best to remove them after a light frost. Irises can be divided from August to September, and the foliage is cut at that time into a fan shape about 3 inches high.

Daylily leaves shed during the winter, so pruning them after a few light frosts is less messy than waiting until spring.