In recent discussions with customers we have been getting a lot more questions concerning exactly what to do to prepare plants, the garden, and the landscape for winter. Hopefully this broad overview will help provide some essential information and direction.
Concerning landscape plants in general, it is still not too late to fertilize if you have not yet done so this fall. Trees, shrubs, and perennials would all benefit from plant foods that are more slow release and focused on supplementing the root development that naturally occurs this time of year as plants get ready for the upcoming winter months and prepare for dormancy and helps them look really great the following spring and summer! We are also quickly approaching the time of year to mulch the plants for the winter when the soil is cooling down. The idea is to provide an insulating layer of 2-3” of fresh mulch in the landscape beds once the ground is colder to prevent the freezing, thawing, and frost heaving that can occur during the late fall/early winter and can damage or disturb plants and their root systems as they prepare for the winter. We prefer either hardwood or pine bark mulches, as they quickly break down and add organic matter to the soil profile. Also falling leaves (once shredded- a lawn mower is good for this!), straw, or compost are all excellent mulches.
We have also been getting a lot of questions as to what needs cut back or pruned this time of year. A good guideline is to prune all perennials back to the ground once the foliage dies and turns brown or black; this typically occurs with most plants after the first few hard frosts or freezes. Certain plants, such as hosta, astilbe, coneflower, etc. will show this die back early while other plants, such as daylily, Shasta daisies, and etc, will last much longer. As long as the plants have green foliage, they can still photosynthesize and build energy for the root systems so should remain as long as possible. Ornamental grasses start to take on stunning aesthetic characteristics for winter interest and for that reason should not be cut back until early spring, before new growth appears. Many deciduous flowering shrubs such as potentilla and spirea can be pruned back rather hard (about halfway) to revitalize the plant and provide much more compact, full-looking growth in the spring with lots of blooms! We usually advise not to trim or prune evergreen shrubs, such as boxwood, junipers, and yews this time of year as it may induce new growth that would not have time to harden off before the freezing winter temperatures. Also it is best not to prune spring flowering shrubs, such as rhododendron, azalea, and lilacs as this will remove flower buds that are already formed for spring bloom! Certain Hydrangeas, including Endless Summer and mostly other pink and blue blooming varieties will benefit from being pruned back about half way this time of year. There are other Hydrangeas, mostly white blooming and oak leaf varieties, that are more woody in nature and should only be pruned modestly to maintain size and shape. Knockout roses, a popular and exceptional shrub rose, should be cut back only about halfway, and mulched and treated like other flowering shrubs this time of year. Other roses, such as hybrid teas and climbers, require more preparation such as pruning back to the grafts (just a few inches above ground level) and mulching several inches over the plant to protect the grafts.
This is also an excellent time of year to fertilize the lawn one final time with a lawn food formulated for fortifying the grass with what it needs for root development, stem hardiness, and preparing it for winter. Also it is not too late to do one last weed control application of the lawn, with an herbicide designed for this time of year. It would be a good idea to keep in mind that all plants, especially ones recently planted, will still be actively growing and developing roots long after the top growth goes dormant and until the soil freezes, so supplemental watering will be necessary until then.
-Provided by Oakland New Albany