Cut back and mound mulch around your hybrid roses
It is time to winterize your hybrid roses, as there have been adequate hard freezes (temperatures in the teens) already this year. These cold temperatures generally occur in late November at the Chicago Botanic Garden, but this year, they came in the middle of November.
Cut back rose canes to about 18 inches and mound the roses with 12 to 15 inches of compost or mulch for the winter. Do not use grass clippings, which will mat down and hold moisture around the plants.
It is best to clean up and remove any rose leaves that have fallen if you had problems with black spot (a common fungal disease). This disease overwinters on infected foliage.
Landscape (shrub) roses do not require this special treatment for the winter. I often see all roses in a garden mounded rather than just the ones that need it.
• Clean out your gutters once all leaves have fallen. Leaves can clog up the gutters and be very difficult to remove once they are frozen in. Monitor weather closely to schedule this work properly.
• Have your garden soil tested to determine how best to manage it 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 choose fertilizers that have little to no phosphorus in them. A soil test will confirm the status of your garden soil. It is best to avoid taking a soil sample if your soil is very wet.
If your soil freezes or is too wet, wait until next year to do the testing.
• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.