As the growing season winds down, it’s tempting to retreat to our indoor activities and put the garden out of our mind until next Spring. There are certain tasks, though, that are best carried out in fall to allow your garden to achieve its full potential the next year. These are our top 5 recommendations to prepare your garden for the (long) winter.
Remove invasive plants
Fall is an ideal time to identify and eradicate invasive plants in the garden. Many invasive species remain green and actively growing much later in the season than natives, so are easy to recognize in fall. This is also the time of year when plants are drawing resources down into the root zone which makes fall systemic herbicide applications especially effective.
Water your garden until the ground freezes
As the temperatures drop many gardeners tend to stop watering. It is important to continue to water, especially new plants, until the ground freezes. As long as air temperatures are over 40 degrees you should continue to water at least twice per month (plants will not be absorbing water as fast as they do during the height of the growing season). In winter, dry conditions can actually be more damaging than the cold itself. Winter winds can desiccate plants (especially evergreens) if they are not able to pull moisture from the soil to replace what is lost through their foliage. Broadleaf evergreens such as Boxwood and Rhododendrons may benefit from a fall application of an anti-transpirant plant protector such as Wilt Stop. This forms a natural, non-toxic, clear flexible film on evergreen foliage that protects it from drying out in winter winds and sun.
Plant spring blooming bulbs
You can add an entire season of interest to your garden with early-season bulbs. Those dreary days of March & April can be spent enjoying abundant bloom rather than just waiting for the garden to wake up. There are few sights more welcome than flowers emerging through the early April snow! A small investment of time & energy spent planting a few spring-blooming bulbs each autumn will eventually produce a spring garden that is the envy of all those gardeners who neglected this simple late-season task. Learn more about Hardy Bulbs for Wisconsin Gardens >>
Remove diseased foliage
If any of your perennials or deciduous trees/shrubs have experienced foliar diseases during the growing season it is important to rake up and remove as much of the infected foliage as possible once it falls from the plant. This will minimize the presence of pathogens and reduce the chance of new infection in the upcoming growing season. It is a good idea to remove the foliage of Hosta plants as well to create a less hospitable environment for overwintering slugs and snails. Most other healthy perennials can be left standing for the winter months as their remaining foliage will provide some protection to the crown of the plant and their standing seedpods may provide winter interest and a food source for native birds.
Mulch cold-sensitive plants
Many people are confused by the concept of winter mulch and apply it too early in the season, thinking that the purpose is to “keep the plant warm”. In fact, winter mulch should be applied only after the ground has frozen as its primary purpose is to keep the ground frozen. This minimizes frost heaving of shallow rooted plants and reduces the chance of plants coming out of dormancy during winter warm spells and suffering die back when new tender growth is frozen off with the return of subzero temperatures. Winter mulch will also help the soil retain the moisture that you made sure was there by watering your garden right up until the ground froze.
Winter mulch should be removed or raked aside in spring so choose material that is easy to handle. Clean straw and shredded leaves work well. Another attractive and effective winter mulch material is evergreen boughs, which are plentiful after the holidays when people are disposing of their Christmas trees. To protect marginally hardy shrubs (such as Roses and some Hydrangeas) from winter winds & sun a temporary cage support can be constructed with stakes and wire and filled with mulch material.