When it comes to cutting back perennials in the fall, there are a few that are best left alone. These perennials are marginally hardy, meaning they may not be able to withstand harsh winter conditions, and cutting them back could actually do more harm than good.
One example of a perennial that should not be cut back in the fall is the garden mum, also known as Chrysanthemum spp. These beautiful flowers are often used to add a burst of color to the autumn garden, but they are not as hardy as they may seem. Cutting them back too early in the fall can leave them vulnerable to frost damage, as their new growth is more susceptible to cold temperatures. It’s best to wait until spring to cut back garden mums, once the danger of frost has passed.
Another perennial that should be left alone in the fall is anise hyssop, or Agastache foeniculum. This aromatic plant is loved by bees and butterflies, and its purple flowers add a pop of color to the garden. However, anise hyssop is not very winter hardy, especially in colder regions. Cutting it back too early can expose its tender stems to freezing temperatures, leading to damage or even death. It’s best to wait until early spring to cut back anise hyssop, when new growth begins to emerge.
Red-hot poker, or Kniphofia uvaria, is another perennial that should not be cut back in the fall. This striking plant with its tall spikes of red, orange, and yellow flowers is a favorite in many gardens. However, red-hot poker is not very cold hardy and cutting it back too early can leave it vulnerable to winter damage. It’s best to leave the foliage intact throughout the winter months, providing some protection for the plant. Pruning can be done in early spring, once new growth starts to appear.
Lastly, the Montauk daisy, or Nipponanthemum nipponicum, is a perennial that should be left alone in the fall. This late-blooming daisy-like flower is a favorite for adding color to the garden in the later part of the season. However, it is not very winter hardy and cutting it back too early can leave it vulnerable to frost damage. It’s best to wait until spring to cut back Montauk daisies, allowing the foliage to provide some protection during the winter months.
It is important to be cautious when cutting back marginally hardy perennials in the fall. Garden mums, anise hyssop, red-hot poker, and Montauk daisy are all examples of perennials that should be left alone until spring. By waiting to prune these plants, you can help ensure their survival through the winter months and enjoy their beauty for seasons to come.