Tips on how best to winterize your garden

It is a good idea to sharpen and clean garden tools when putting them away for the season. Well-maintained tools make gardening much easier. Use pegboard on your garage walls to hang and organize tools. Have your snowblower serviced before the first big winter storm of the season.

Winterize your hybrid roses. Wait until there have been two to three hard freezes (temperatures in the teens) which typically occur in late November at the Chicago Botanic Garden. Cut back the rose canes to about 18 inches and mound the roses with 12 to 15 inches of compost for the winter. Well-established shrub roses do not require this special treatment for the winter.

In most cases tree wrap is not needed for newly planted trees. If used, it should be removed within six months to a year. Tree wrap is used in certain areas of the Chicago Botanic Garden to help prevent animal damage in winter. These trees are wrapped in October and November and the wrap is removed in April. Both paper and burlap tree wrap work well. When using paper tree wrap, place the printed side against the trunk so it cannot be seen when wrapping is completed. Start wrapping the tree at the bottom of the trunk and finish at the top.

Evergreens planted over the previous three years should be watered deeply if conditions are dry. It is best that they do not go into winter under any drought stress, which will make winter burn of foliage more likely. Make sure the root balls of evergreen trees are thoroughly moistened when watering. Densely branched evergreen trees can shed water from rain or a sprinkler away from the root ball, as can well-established evergreens. Apply water directly to the root zone of these plants.

To calculate the amount of mulch needed for a bed, first convert all measurements to feet. To figure the square feet of a bed, multiply the length times the width. To convert the depth of mulch (we recommend two inches) to feet, divide by 12. Use the following formula to calculate the amount of mulch needed to spread 2 inches over a bed that is 18 by 37 feet. Eighteen times 37 equals 666 square feet of bed space. Two inches divided by 12 inches equals .17 feet. Six hundred sixty-six square feet times .17 feet of mulch equals 113 cubic feet of mulch. One cubic yard of mulch is 27 cubic feet, so divide 113 cubic feet by 27. Your order will be four cubic yards of mulch.

Should you use bagged mulch or buy mulch in bulk? Bagged mulch comes in different sizes, typically two or three cubic-foot bags, and works well for small beds. For the bed above you would divide the 113 cubic feet of mulch required by the amount of mulch in the bag: 113 cubic feet divided by 3 cubic feet per bag equals 38 bags and 113 cubic feet divided by 2 cubic feet per bag equals 57 bags of mulch. For this bed it will be less expensive to buy the mulch in bulk.

Have your garden soil tested to determine how best to manage and what fertilizers to use. Make a composite sample from a few areas in the bed and send in for testing. If your garden is large it is a good idea to break the garden into zones to test. Soils in the Chicago area tend to have adequate phosphorus levels so in these situations choose fertilizers that do not have phosphorus in them or, at least in very small amounts. A soil test will confirm the status of your garden soil.

Make your last application of fertilizer for your lawn in late October or early November. Use one pound of nitrogen per 1,000 square feet of grass. For example, if you have purchased a 24-5-10 bag of fertilizer and have 5,000 square feet of lawn use the following calculations: One pound of nitrogen divided by .24 = 4.17. Multiply 4.17 by 5,000 square feet of lawn = 20,850; then divide by 1,000 = 20.85. You now need to use about 21 pounds of 24-5-10 fertilizer to cover the entire lawn.

For a unique bulb display in spring, plant bulbs in containers. It is possible to layer bulbs in the container to create a dramatic display of bulbs. Keep the container in an unheated garage over winter. An attached garage will work best if the containers do not freeze solid. Water in well at planting time and provide some supplemental water as needed during remainder of fall. The bulbs will be forming roots during this time. Move the pots outside as the weather warms in spring and the bulbs will grow and flower. Move back in garage if a hard freeze is predicted.

ŸTim Johnson is director of horticulture at Chicago Botanic Garden.