WINTERIZING is the practice of getting the garden and landscape ready for cold temperatures. Winterizing chores include cleanup of dead plant materials and fallen leaves, mulching, fertilizing, digging and storing tender bulbs. Trees and shrubs also need attention at this time and of course the water garden needs to be prepared for winter.
Why winterize?
The effects of winter freezing and thawing are hard on plants, therefore it is wise to spend a little time at the end of the growing season to protect your investment (and hard work). Interestingly, the object is not to keep the cold from reaching the plants but to keep them cold .
Damage can occur from dehydration as well as the effects of fluctuating temperatures which
freeze and then thaw the ground, causing heaving of the plants . Snow acts as an insulating blanket that protects perennials. However, our zone (5/6) does not normally get a cover of snow through the season. Mulches in the form of shredded leaves, compost, and even topsoil can protect the crowns and roots of your perennials.
With a few exceptions, trees, shrubs and perennials sold by garden centers and nurseries in this
area are chosen based on hardiness for our zone. Hardiness zones are determined by the US
Department of Agriculture based on average low temperatures during the winter. A plant is
considered ‘hardy’ if it is capable of withstanding the average conditions of winter in that zone.
Adventurous gardeners throw caution to the wind and push their zone. Winterizing then becomes extremely important in order to protect these plantings.
Proper care during the growing season will help insure that your permanent plantings winter
successfully. Infrequent, deep watering encourages roots to grow downward in the soil. Give plants only the fertilizer they need. Avoid fertilizing later than mid-August. Plants growing in soggy areas usually have a harder time in winter. Improve drainage with lots of organic matter. Always deal with the problems of pests and diseases immediately.
Adequate moisture content in the soil before it freezes is important. If the soil is dry an inch or two below the surface, give the area a thorough soaking before storing hoses and draining faucets and sprinkler systems.
When should I winterize?
With a few exceptions, the process starts with a killing frost. At this point, tidying the garden of
fallen leaves and the dead and dying leaves and stems of your annuals and herbaceous perennials begin.
Clean-up
To begin with, you need to make some decisions about how much of the garden can be left for
winter interest. It is not necessary to remove all of the dead plant material. Ornamental grasses in particular are very beautiful in the winter landscape. The seed heads of many perennials provide beauty and function as a food source for birds.
Remove annuals from the garden. Special attention should be given to removal of diseased plant material. It is not recommended that they be used in composting or mulching. All other plant material may be taken to the compost pile or left in place for insulating.
Division and Transplanting
Divide spring blooming perennials in the fall. Do not take too many divisions from one plant.
Each division must have enough root to sustain growth. It is recommended that ornamental
grasses be divided in the spring. Irises and daylilies prefer to be divided in August.
Pruning
Be sure what you are pruning in the fall is not your potential blooms for next spring. Do remove
dead branches.
Lawn
Lawn care in the fall will ensure maximum results the following growing season. Mow the lawn
at a lower level , no higher than 1.5-2 inches. As fall arrives, reseed areas as need. Apply
herbicides in September to control weed infestations. The last fertilizer of the year should be
high in phosphorus and potassium and low in nitrogen. Aerate if the soil is compacted or if
thatch is a problem.
Mulching
∙ It is important for the ground to get cold before mulching. Plants should be in a dormant
state before protection is applied.
∙ Fallen leaves (except oak) and saw dust should not be used in mulching since these compact
and actually promote disease. Leaves that have been shredded may be used and actually are a
good idea because as they decompose they add beneficial nutrients to the soil. The exception
is walnut leaves which are to be avoided since they are toxic.
∙ Topsoil and compost are both suitable mulches as are pine needles, evergreen boughs, straw
and hay.
∙ A layer of 4 to 6 inches of mulch is recommended for most perennials.
∙Do not mulch bearded iris. The iris borer seems to be worse on mulched plants.
Trees and shrubs
Fall is an excellent season for planting trees and shrubs. Be sure to apply plenty of water before
the ground freezes. Do not fertilize or prune branches until spring. Trunks of young trees are
susceptible to winter injury, especially those with thin or dark bark. Wrap the trunks with
commercial tree wrap.
Roses
Rake up and collect fallen leaves. Remove old mulch and dispose. Spray plants one final time
with fungicide, making sure to spray all canes and the base of the plant. Cut back canes to about
3 feet. Apply a dot of Elmer’s Glue to cut tip of cane to prevent cane borers. Plants shorter than
2.5 feet should not be cut. Water plants thoroughly unless soil is moist. Add a foot of soil or
mulch down the center of the plant, enough to cover the bud or graft union. Rose collars may be applied and filled with soil or shredded leaves as an alternative. If rose cones are used be sure to poke several small holes in the top for ventilation.
It is difficult to winterize the long canes of climbing roses. Protect the base as with other roses
and tie down long canes so they are not whipping in the wind.
Azaleas and Rhododendrons
Rhododendrons and Azaleas should be well-watered as they go into their dormancy period. If
the fall season is dry, continue a regular watering schedule and soak the plants one last time
around Thanksgiving.
Use mulch on top of the root ball to help conserve water loss and as an insulating medium when the weather gets really cold. If you don’t use mulch, you run the risk of “winter burn”. This
happens when the ground is frozen but the air temperature is not. The leaves start to lose
moisture, call downstairs to ask the roots to send up some more water, but because the water is frozen, it doesn’t get up to the leaves. The leaves dry out and turn brown on the tips. Be sure to pull the mulch away from the trunk of the plant.
Anti-desiccants are wax based products which coat leaves and protect them from moisture loss.
Broadleaf evergreens such as rhododendrons, azaleas, and hollies benefit from anti-desiccant
sprays such as Wilt–Pruf. Do not spray the under side of leaves.
Tender Bulbs
Dig tubers or bulbs with a spade. Don’t worry about cleaning the soil off at this point.. Allow
soil to dry for about a week. Knock off loose soil and dust or spray for pests before storing in
cardboard boxes between layers of vermiculite, sawdust or wood shavings. Be sure to label
bulbs and tubers before storing.
Cannas: Dig before the ground freezes and store as above. Ideal temperature 50-60 degrees
Tuberous Begonias: Dry tuber and store as above. Ideal temperature 50-60 degrees
Dahlias and Tuberoses: After a light frost cut to 4-6 inches above the soil. Dig and store as
above. Ideal storage 35-45 degrees.
Calla Lillies: Dig when leaves have yellowed and died after a killing frost but before the
ground freezes. Store as above.
Gladiolas: Dig corms after foliage has matured and turned brown. Cut tops off one inch above
corm. Remove the old corm which is beneath the new one. Place corms in an onion sack or old
nylon stocking and hang from a wall or ceiling. Ideal storage 35-40 degrees
Caladiums: Dig and store before freezing. Store at temperatures above 60 degrees.
Container Gardens
Terracotta and ceramic planters must be brought inside for the winter. Remove plant material
and soil to the compost pile. If you wish to bring your container grown tropicals indoors, be
sure to treat for insects before moving inside. You might want to remove the plant from the pot
and replace the old potting soil with new.
Potted standard roses could be moved to an enclosed porch or garage. Don’t forget to water
sparingly from time to time. If left outside, lay on their side and cover with a thick layer of
mulch.
Clean and store birdbaths.
Water Gardens
Don’t let falling leaves accumulate in your pond through the fall. Rotting leaves at the bottom are a major cause of algae. Hardy aquatic plants can be placed at the bottom of the pond to over-winter. Dividing overgrown plants is best left for spring. Tropical water lilies need to be removed, cut back, and stored in a cool basement covered in wet burlap. Don’t let them dry out.
With preformed pools, don’t empty the water because the weight of it will keep the pool firmly
in the ground. You can drain it in the spring and refill it. Be sure to remove equipment like
pumps, jets, lights and the transformer and store in a dry place after cleaning.
