Preparing Perennials for Winter
As cold weather approaches, take a look at your perennials. After a couple of hard frost some of your perennials may start to go dormant. You will see them turn color, wilt and look dead. You may be tempted to cut them all back and put mulch around them. I would ask you to consider leaving some types alone until spring- like coneflower, black eyed susans, ornamental grass, yarrow, butterfly bush and others with seed heads. This will provide some food for birds and provide some interest throughout winter. Also, wait to mulch until just after the ground freezes and you only need a 2-3” layer. You want the ground temperature to be as constant as possible and the mulch will help to do this. If you have any perennials that are marginally hardy you may want to add extra protection on these. You can use extra mulch, leaves (not too many maple leaves), or branches of evergreens to help further insulate and protect them from winter. Remember to pull away this extra protection in spring to let the soil warm up faster and also to let the plant grow and not fight to get thru the extra protection.
Many perennials do not have any winter interest and cutting them back will tidy up your garden. Perennials like hosta, delphinium, and coreopsis would be some examples. It is best to cut them down near ground level. Make sure not to cut any green foliage that may be near the soil line of some perennials. Also, clean up any foliage on the ground and what you cut and throw it away. Leaving old leaves on the ground can be a place for disease and insects to over-winter.
This is also a great time to think about next year. As you are cleaning up the garden, think of where you might want to add other perennials and put markers in the garden now. Sit back with a blanket on your lap and dream of next spring and how your perennials will look. Remember that the snow coming in winter is like that blanket on your lap for the perennials as it helps to keep them ‘warm’ from the cold temperatures.