Clean up of perennials can be done at any time. However, due to tough weather in the winter, it’s best to do it either in the fall or spring. You can clean up your perennial garden or food forest in a number of ways depending on the plants you have and the contribution of the perennials to your landscape aesthetic.
Take the following steps to clean up your perennial garden:
1. Remove dead plants
Cleanup in the fall mainly involves the control of pests and diseases. Rake up old leaves and debris to remove potential breeding grounds for pests and other harmful insects.
Old and decomposing plant material can harbor diseases such as fungal spores which may infect your new plants in spring.
2. Prune your plants
You should cut back foliage in the fall to help your spring perennials. Do not cut them all the way to the ground. Leave some to protect the crown during the harsh weather of winter. The recommended height for cutting foliage is 2 to 3 inches above the soil.
3. Spread your compost
Proper management of your compost pile is vital to preventing seed bloom and mold during winter. Spread the pile to offer protection to the tender perennials and add a layer of nutrients over the beds. This also helps with weed control. Once spring comes around, you will have an easier time tilling through the compost.
According to the USDA plant hardiness zone, you can leave debris as a protective cover for tender perennials in zone 7.
For other zones, it is best to do a fall cleanup, as a time-saving strategy for gardening in spring. You will have an easier time cataloging your plants and preparing new orders for spring cleanup.
4. Weed and compost
During early spring, you can start weeding and composting. The soil is damp, so it is easier to uproot the weeds. You can collect the uprooted weeds and foliage into your compost pile. Start a new pile in spring for future use, and use your old pile for your current garden.
It is important to inspect the pile for any plant material that shows signs of disease as it may impact the integrity of your compost and infect your new plants.
When should perennials be cut back?
The time to cut your perennials depends on your USDA zone, the plants in your garden and your availability to garden.
The best time to clean your perennial garden is during spring. It is challenging to clean up during winter, because the soil may be too hard or too wet to handle. Further, leaving foliage during the cold season can help protect their crowns. If your garden is wild, you can read my article on how to tame a wild garden.
Spring is perfect for your perennial cleaning, as it is easier to dig the ground and remove overgrowth to create a beautiful garden.
Many perennials are best left standing through winter for better protection. Once spring arrives, look to prune woody plants to allow blooming on new branches. Woody perennials will often open their buds on the base of the plants in the initial stages of spring. As a gardener, this is the time to start pruning.
During spring you can clean up your evergreen and semi-evergreen perennials and woody plants. These are left to stand during winter and require immediate attention during the initial stages of spring to prevent overgrowth.
Chores such as hard pruning and edging are best done during the spring. Observe the perennials which have finished blooming and prune them appropriately to encourage new growth. The following plants can be pruned post-bloom; daylilies, perennial geraniums, coreopsis, Shasta daisies, lungwort, Heuchera and Epimedium.
Ornamental grasses should also be cut back during spring. Evergreens require little care during spring. They are actively growing during this season and just need a little fertilizer to facilitate their bloom.
During fall it is best to clean up if you are wary of diseases and pest buildup during the winter. You can clean up the following perennials, Blackberry lily, Garden phlox, Bee balm and Bearded Iris, Ligularia, Hosta and Brunnera.
If you want to prevent reseeding of certain plants, it is best to cut your perennials in the fall. Cut off old flowers just below the foliage to give a tidy look. You can cut back the following perennials: Jupiter’s beard, Turtlehead, Blanket flower, Black-eyed Susan, and Purple coneflower.
What perennials should not be cut back in the fall?
You should not cut perennials that have an aesthetic impact on the landscape during winter. Some plants have good height and structure which remain prominent during the cold season.
These include zebra grass, blue false indigo, switchgrass, Siberian iris, and Joe Pye weed. They stand out in the snow and their appearance makes sure your backyard remains beautiful during the winter.
Do not cut perennials that provide food for birds and are beneficial to certain insects. Some birds such as goldfinches rely on seed heads of certain perennials for food. These include purple coneflower, oxeye sunflower and Black-eyed Susan.
Some insects hide close to native plants in the winter to shelter from predators or harsh weather. Avoid raking plant debris or digging around your perennials in the fall to ensure the insects benefit from your garden.
Avoid cutting evergreen or semi-evergreen perennials in the fall. They include heucheras, diunthas, hardy geraniums, hellebores, ornamental grasses, milkweed, cranesbill, stonecrop, and epimedium.
Some perennials need protection during winter. Do not cut back red hot poker, garden mums, Montauk daisy and anise hyssop. They can survive the difficult weather during winter. Let the foliage grow in order to collect snow for moisture and insulation.
You can cut back your perennials in the fall or spring depending on the type of plants available in your garden. During the fall, you should cut the foliage of certain plants to a height of 2 to 3 inches above the ground.
You should avoid pruning foliage of evergreen plants, hardy perennials and the plants that provide habitat and food for birds and insects during winter. Fall cleanup is good to prevent diseases during winter and to allow easier garden management in spring.
Spring is a good time to clean up your garden. Some plants have grown wild during winter and you need to cut back to allow them to bloom. Cut the foliage and clear debris from the bases of the plants to accommodate new growth. You should know the type of plants growing in your garden, and the hardiness zone to guide you on how and when to clean up your perennials.