Trees, shrubs and small flowering plants may seem happy in the cooler fall months, but now is the time to be sure they're getting the water they need to stay full and healthy and have their root systems be adequately satiated so that they have the power to withstand the cold, harsh winter.
Your watering regimen will depend, of course, on whether your trees and shrubs are newly planted or more established. According to the experts at the New York Botanical Garden, you should "water your trees well when they are newly planted. Give them a deep soak on the day of planting, and then come back the next day and soak them again. The ground around the root ball of the tree will take up most of the water from the first day, and the second watering ensures that the root ball gets soaked."
Soaking the root ball encourages it to grow below ground, sending out a strong network of additional roots. If you do not give newly planted trees and shrubs this daily watering to start them off or water often during the first weeks of their planting, the root balls will not send off systems of roots, or those roots will extend sideways, not deep into the earth as you want them to. When a newly planted tree or shrub does not get adequate watering during fall plantings, the root ball can shrink, creating an air pocket around it that can cause your plant to suffer over time or not survive the winter.
The New York Botanical Garden's expert team says, "Once your tree is established, be vigilant about your watering for at least two years. It is important to remember to water during dry spells in the summer and fall."
*Protecting During Winter
David Beaulieu, the About.com gardening guide, warns about the damage that trees and small plants of any establishing stage can experience during the winter. "The winter damage to which trees and shrubs are susceptible often stems from their inability to draw water from the frozen earth," he says. "Although we don't necessarily equate wintry conditions with desert conditions, the winter landscape in cold climates is, essentially, a desert, making plants susceptible to winterburn." Properly watering the plants in fall, then, can minimize injury to trees and shrubs during the winter.
Another winter threat that can be minimized with fall watering is root damage caused by the seeping in of salt from nearby road treatments. Salt applied to roads and then plowed onto your property, carried farther onto your lawn and garden beds by melting and winter precipitation, can damage your plants' roots. So when you experience a "winter thaw" day, it's wise to give your trees, shrubs and small plants a good watering a few hours before temperatures are expected to drop below freezing. The wash of clean water carries salt buildup away and gives your plant a healthy drink.
*Fall Watering Tips
--Watering plants sparingly throughout early autumn, until the leaves of deciduous trees fall, allows the plants to undergo their "transitional phase," during which they conserve energy and do not produce new shoots.
--When you see the deciduous leaves fall, that's your signal to start watering plants more often and more deeply to allow them to prepare themselves for winter.
--In late autumn, give both evergreen and deciduous trees and shrubs a deep watering.
--Newly planted trees, shrubs and other plants need to be "watered to establish," so make sure you're planting trees early enough in the fall to allow for four or more weeks of deep watering before the freezing temperatures arrive.
--Deep watering will help a plant send new roots deep into the earth, even if you haven't watered it religiously during its first few weeks in the ground. Plants can be "retrained" to send down deeper roots with greater watering now.
--Create a berm, or a ring of dirt and topsoil with mulch on top, around each plant to capture any rainfall or watering. This mound of earth will deliver water to the root system.
--According to Orchard Nursery, you should "run your sprinkler to the point of runoff and then turn it off and allow the water to penetrate. Determine the efficiency of your sprinkler by using the 'can test.' Set out open-topped cans on different sections of your lawn or garden to see how much water collects in each can as the sprinkler sprays water in its track." Adjust your sprinkler position as needed. And always water in the morning so that plants have time to dry off before nightfall. Watering at night produces rot.
--"Plants with leaves that are smaller, grayer or needle-like are all adapted to require less water," says Orchard Nursery.
--Plants situated on slopes require berms and basins to catch runoff water from rains and watering to deliver water to their roots.
--Check your irrigation systems for clogs and inefficient spray at this time, and either clean them or get new ones.