Consumer Horticulture Agent
Milwaukee County University of Wisconsin-Extension
We have had so many beautiful autumn days to work in the yard this year. The more you accomplish now the less you will need to do in the spring.
Empty, clean and store planters where they will be dry for the winter. You can dump them into the vegetable garden or in a pile with roots, soil and all. Break up the root ball a little and let the freezing and thawing of winter do the rest.
Statuary and garden art will hold up better if stored out of the elements during the winter, too. Of course, some of it, especially if it’s metal or iron adds character to the garden during the drab months to come.
Hardy plants growing in planters or still in their nursery containers for a variety of reasons need insulation from the extremes of winter. These can be buried to their rims in a vacant spot in the garden or into a window well and stuffed with straw or leaves or put into a box in an unheated garage and then packed with materials to insulate the roots such as straw, rags, packing peanuts or dry fall leaves. They can be left outside if the pot is surrounded by a thick, tightly packed layer of straw or, better yet, whole bales of straw.
If you are using a rain barrel or two to conserve water and reduce stormwater runoff, they should be emptied and turned over to keep them dry during the winter months. Reconnect your downspout to direct the snowmelt and winter rain away from your foundation.
After they have gone dormant and the ground has frozen an inch deep, roses and other half-hardy or tender landscape plants such as chrysanthemums need to have their stems and the soil above their roots insulated in case this winter is drastic. Then pile some soil up around the base before surrounding them with chicken wire and stuffing it well with dry leaves reserved from this year’s leaf collection.
Wait until spring to prune trees and shrubs unless the branches are an obstruction you cannot live with that long. Pruning wounds will heal quicker in spring and cause fewer disease problems.
Cole crops like Brussels sprouts, cabbage, broccoli, collards and kale are made sweeter by frost so don’t pull them out yet. Harvest them as long as possible.
Instead of harvesting less hardy late season crops, leave them in the garden and tuck them in with a thick layer of straw so they don’t freeze as early. This includes carrots, beets, leeks, rutabagas, turnips, winter radishes, chard, Chinese cabbage and leaf lettuce. Cover the leaf lettuce first with floating row cover fabric which breathes but will keep the straw out of your salad.
Spring flowering bulbs can still be planted as long as the ground is not frozen. For really early spring flowers, try the ‘minor bulbs’ like Serbian Squill, Glory of the Snow, Snowdrops, and Puschkinia. Be sure to drench them well with water at planting.
Check houseplants for insects that may have come indoors as you brought the plants inside. Pick pests off by hand or use insecticidal soap or ultrafine oil to control. Give foliage a sponge bath or shower regularly to keep leaf pores clear.
Outdoor planters, hanging baskets, and window boxes should be emptied and washed thoroughly with soap and a mild bleach solution before storing for next year.
Lawns left too tall over the winter encourage disease problems like snow mold and tunneling of meadow mice. Once the leaves are all off the trees, mow one final time at 2 – 2 1/2 inches.
Mark or make a mental note of lawn areas infested with crabgrass this year so you can spot treat with a pre-emergent herbicide next spring. Crabgrass is easy to see now since it turns purple and then brown when killed by frost.
Prune everbearing raspberries if you did not do so after this fall’s harvest. If you cut or mow all canes to the ground now there will be no spring harvest but a larger fall harvest next year. It also reduces insect and disease problems.
Water all needle and broadleaf evergreens one last time before the ground freezes since winter wind and sun will continue to demand water from these plants through their leaves all winter. Excess water loss can lead to “winter burn” or death.
Amaryllis bulbs that have rested for at least 10 weeks can be repotted, watered and brought into a bright room to produce flowers for the holidays.
Keep checking tomatoes and other produce in storage discarding the rotting fruits and using those that have colored up.
Protect tree trunks from damage by the chewing of mice, voles, rabbits and other pests. For this use plastic or wire applied at least 1 – 2 feet higher up the trunk than the expected snow level. Reduce nesting sites by clearing away weeds, tall grass and leaves from the base of the trunk.
Move pesticides and plastic equipment to someplace where they will not freeze. Always store pesticides in locked cabinets or up out of reach of children. Keep them in their original containers. Cover labels with clear plastic tape to keep them clean and legible. File supplemental label information where it can be easily found and referred to before application next season.
Stop fertilizing indoor plants now since they will use less water and nutrients until next spring due to the lower light levels.
Keep flowering Thanksgiving cacti well watered and out of drafts. Avoid moving them while in flower since this may cause them to drop flower buds.
Cut down and discard asparagus stems and ferns (leaves) that have yellowed completely. Removing these from the garden reduces disease and insect problems next year.
Take soil samples for testing by the UW Soils Lab or other State approved lab. Separate samples should be taken from areas that are used for different purposes or have different light and moisture conditions. Combine several individual samples from a single area to make a composite sample. More information can be found at http://uwlab.soils.wisc.edu.
If the soil has frozen at least an inch deep, you can now apply protective mulch to woody plants or herbaceous perennials that are growing in above ground planters. You can first surround the planters with chicken wire or hardware cloth leaving enough room for at least 6 inches of tightly packed straw right up against the container. Cover the top with twice as much straw held in place with plastic or boards.
Tender hybrid roses can be mounded with soil and then caged in chicken wire now even if the soil is not frozen. After the soil has frozen, stuff the cages with those dry leaves you saved. Rose canes do not need to be cut back until next spring but should be tied together to prevent whipping and rubbing against the wire.
Now it’s time to cover even the cole crops such as broccoli, Brussels sprouts, kale, cabbage, turnips to prevent them from freezing solid.
This is a good time to clean, sharpen, and oil garden tools and equipment. Oil and store gas powered equipment like lawn mowers and leaf blowers. Repair shops are in a slow period (at least until the snow flies and snowblowers need repair) so arrange for a tune-up and blade sharpening now.