I planted a few evergreens this summer and was wondering if this fall’s warm weather means that I should be doing something special to help the plants.
— Larry Jones, Warrenville
This fall has been unusually warm and dry, so you are right to pay extra attention to your evergreens. Be sure to give additional water to any evergreens planted over the previous two years. I did some planting in my garden this year and have found the extra time that I have spent watering this fall to be very annoying, but there simply has not been enough rain for new evergreens to establish properly. All plants installed this year should also be getting supplemental water this month. Deciduous trees and shrubs and perennials that lose leaves in winter are going dormant now, so they require less water. It is easy to forget about watering during November’s colder weather. This year, that cold weather is arriving late and at the end of a busy gardening season. Evergreens that were planted recently should not go into winter under stress from being too dry. This stress increases the chance of winter burn and
possible loss of trees. The newer the tree, the more important it is to provide supplemental water in late fall as needed. Evergreens can lose moisture from their leaves faster than the roots can replace it from frozen ground when there is low soil moisture, freezing temperatures and blowing wind. Make sure the root balls of evergreen trees are thoroughly moistened when watering by applying water to the base of the plant. Densely branched evergreen trees can shed water from rain or a sprinkler away from the root ball. Automatic sprinkling systems typically do not apply enough water at the base of evergreens and are being turned off now in preparation for winter. Over time, new trees will grow roots out into existing garden soil, making it less important to apply water at the base of the trees.
It is also a good idea to add 2 to 3 inches of mulch around the trees. This will help conserve moisture, mitigate temperature extremes and keep the soil warmer later in the fall for root development. Keep the mulch about 2 inches away from the base of the tree. The mulch also looks nice and helps keep weeds down in the coming year. Bagged mulch is readily available at garden centers.
Disconnect garden hoses from outdoor spigots and faucets as night temperatures begin to drop below freezing. Reconnect hoses to water as needed during dry spells. If you leave a garden hose attached, a small amount of water can stay lodged in the pipe by the spigot and quickly freeze. This ice can damage your faucet and pipe. Once you have finished watering for the season or if there is a very cold night or an extended period of cold in the forecast, turn off the water supply inside your house, disconnect hoses and tighten all the faucets after opening them to drain out any remaining water. It is important to keep water out of exterior pipe systems that will not be used in the winter because trapped water can freeze and expand, causing cracks and breaks and even bursting pipes.
Some homes have frost-free faucets on the side of the house. These are standard hose spigots with a long pipe on the back end that extends through the side of the house. It looks the same as a regular spigot from outside the house, but the connection and valve that control the water supply are inside, where it’s warmer and protected from freezing. A properly installed frost-free faucet has a slight downward pitch toward the spigot so that water will drain from the pipe when the water is turned off, leaving no water to freeze in the pipe. If you are unsure whether your faucets are frost-free and installed properly, have a plumber inspect them to avoid a broken water line and a big mess in the house.
For more plant advice, contact the Plant Information Service at the Chicago Botanic Garden at plantinfo@chicagobotanic.org. Tim Johnson is senior director of horticulture at the Chicago Botanic Garden.