With winter just around the corner, for many of us it’s time to put gardening on hold. But before you do, it is important to take measures to protect and prepare, or “winterize your garden,” in order to ensure a good growing season next year. Completing these few simple tasks can make all the difference for your plants’ health and survival through this harsh season.
Clean up and cut back
Weeds and dead plant material should be the first to go. Many stubborn weeds may be easier to find and remove after the first killing frost. Deep rooted weeds will come out more easily in moist soil, so be prepared with a watering can and a digging fork. Search out as many weed seedlings as possible now; otherwise in the spring they will take off like a thousand rockets and be much harder to get a handle on.
Annuals can be cut back to the base and composted, unless they suffered from infestation or disease, in which case they should be completely removed and destroyed.
Any dead or diseased shoots from perennials should be cut back to the base. Phlox, bee balm and peonies tend to host mildew in the later months, and should be cut back. Healthy perennials can be left standing, however. This not only ensures the integrity of the crown, but the dead foliage serves as a habitat for beneficial insects, and their flower heads can provide important forage food for wildlife.
If you are fortunate enough to have brambles, they will need selective thinning. Left to their own devices, they may easily get out of control, so limit your row width to one or two feet, depending on whether you have access from one or both sides. All second year growth should be removed, as it will no longer produce (these are the thick dead-looking stems). To ensure proper air circulation and help prevent disease, the remaining canes should be thinned to approximately one per six inches, keeping the largest, healthiest-looking shoots.
Depending on the variety, this may also be a good time to prune your hydrangeas; but most shrubs, especially lilac, forsythia, and oakleaf hydrangeas should not be pruned in the fall, as this will remove their already-developing flower buds.
The ground is going to freeze in any area with a real winter. Making sure the soil has proper moisture and a layer of protection will help insure root health for all the permanent residents of your garden. A top dressing of compost is welcome for most plants, and mulch over shallow rooted specimens is encouraged. If you’ve had a dry autumn, be sure to give your garden a good drink before turning off the hose or taking down the water-barrel.
The question of leaf raking is up for debate. Many recommend removing leaves as quickly and thoroughly as possible to avoid the risk of fungal infestations within the moist plant matter; while others see leaves as a viable substitute for mulch.
My suggestion is, as with many things, “take the middle road.” Rake the first couple fallings to prevent the accumulation of a thick layer of wet leaves which could be detrimental to your garden and suffocate any lawn, but allow the last falling to provide a loose layer of protection which will readily decompose and act as a fertilizer in the spring. Properly composted, leaves make a rich humus matter that adds to soil structure and fertility.
Mulch, too, is a bit tricky. In climates that see frequent freeze-thaw cycles (USDA Zones 7 and 8), a couple inches of mulch will prevent roots from becoming exposed and damaged; but unnecessary mulching can indirectly cause damage, as it locks in moisture, inviting mold and fungal diseases.
Mulching perennials in cold climates is likely to benefit them, especially if they are newly planted or tender. When mulching shrubs and trees, however, avoid contact with the stems. The bark itself is protection, but it can be compromised if piled with mulch. Shredded leaves, bark chips, pine needles and straw are all good choices for mulch material. Wood chip mulch can temporarily deplete the soil of nitrogen, and should be reserved for top dressing over other materials.
The combination of icy temperatures and high winds can have a desiccating effect on young plants. Trees and shrubs that are just getting established will do better with a layer of protection through the winter. Avoid impervious materials that may collect moisture and invite mold or mildew. Materials like burlap or floating row cover fabrics allow for penetration of moisture along with moderate airflow, while providing a buffer from the wind.
Many fig gardeners choose to wrap their plants to reduce the loss of fruiting stems. Broadleaf evergreens and roses also benefit from a covering in extreme cold, as do perennial herbs like lavender, thyme, and oregano that are in exposed areas.
Potted plants that are too large to be moved will need extra protection around the pot. Because it is above ground, the contained soil will be subject to frequent freeze and thaw cycles in areas where winter temperatures fluctuate; but pots can be protected with several layers of burlap, or a cushion of collected loose leaves.
When temperatures start to drop below freezing, tender plants will suffer damage, or even die. Potted plants like begonias, geraniums, and oxalis that have enjoyed the fresh air up until now, will want to be brought back indoors. Cut them back a bit, and keep them in a cool, sunny window for best results. While most annuals will have to be sacrificed, it is possible to pot up some tender herbs, like basil and marjoram, and overwinter them indoors.
Tender bulbs like gladiolus, cannas, and dahlias should be removed in hardiness zones of seven and below. Carefully dig the bulbs and shake off excess soil. Stack them loosely in a well ventilated area – like a garage. When the leaves dry, trim them off, and store the bulbs in a cool (but not freezing) dark location – like the basement, until it’s time to re-plant in the spring.
By erecting a simple cold frame or primitive greenhouse, vegetable gardeners may be able to keep a continuous crop of greens like arugula, kale, lettuce, tatsoi, and spinach. Lining your beds with straw bale walls and giving them a ceiling of old windows can create a quick greenhouse effect, prolonging the life of your favorite hardy vegetables.
Plants like rosemary, Swiss chard, and parsley can often endure the whole winter if given enough protection. Don’t be afraid to experiment and see what works. In most cases, other than your time and effort, you’ve got nothing to lose by trying.
With cold hardy plants, a simple row cover can add weeks to your harvest. Although little to no growing takes place in the winter, plants that have been protected are quick to revive and thrive in the spring.
If you have an active compost pile, you’ll want to keep it alive. Piling straw or bagged leaves around the perimeter can help maintain the warmth generated by, and necessary to the living organisms that make the magic happen. Harvesting any usable compost before the onset of winter will make room for continued winter composting, and make your garden happy as well.