It is best to keep any logs that you saved for burning in the fireplace outside until you are ready to burn them as insects can come in with the firewood. Never treat firewood with insecticides. Also, do not transport any ash wood outside of the emerald ash borer quarantine zone to avoid further spreading of this insect.
Continue cutting buckthorn out of native areas during the winter. There will be less impact on herbaceous native plants when this work is done on frozen ground. Be sure to treat stumps with an herbicide such as glyphosate or triclopyr herbicide to kill the root system. Glyphosate needs to be used at a high enough concentration to work as a stump treatment. Some recommend a 50 percent concentration -- Botanic Garden staff has had success with a lower concentration of around 30 percent. One of the drawbacks with glyphosate is that it is water-based and will freeze at below zero temperatures and is only effective on the cut surface. Triclopyr is the preferred method because it is oil-based, effective through the bark and on the cut surface and will not freeze.
To keep cut flowers fresh, place them in room-temperature water as soon as possible. Protect the cut flowers from exposure to freezing temperatures outside. With a sharp knife or pruners, make an angled cut and remove a minimum of one inch from each stem. Ideally, make this cut while the stem is under water. Cutting on an angle increases the surface area for water intake. Add floral preservative to the vase water. Most preservatives contain an acid (to neutralize alkaline tap water) and an ingredient to discourage bacteria. Remove all foliage below water level. Cut flowers prefer a cool, humid environment and should be kept out of bright light and away from heating vents. Do not place cut flowers close to a bowl of fruit or vegetables since the ethylene gas emitted by ripening fruit can damage the flowers, as can cigarette smoke.
• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.