Evergreens benefit greatly from an application of water just before freeze-up. Over the long months until spring, the plants’ systems are naturally barely active but the roots and mycorrhizae are often still functionning, so a moist soil reduces stress and helps initiate stronger new growth in springtime. Native plants generally respond to day length when preparing for both ends of winter. Plants introduced from other climates can adjust in time, but an early freeze-up can surprise them, causing die-back of last year’s growth which hasn’t yet ‘hardened up’. This is one of the reasons to wrap young plants, particularly evergreens – to help them moderate temperature changes and filter out cold, drying winds. Wrapping is best done using an open, loose fabric like sacking or burlap. This enables air circulation, preventing disease while allowing transpiration to continue.
Photo credit: Davey Tree Service Blog
Another important aid to trees is to plant them close together so that they can support each other; their root systems as well as their shared canopies will reduce the drying effect of winds. Adding mulch and fallen leaves around the tree base also regulates soil temperature and water evaporation. Existing large trees act as nurse trees for young trees planted near the edge of their canopies, helping the new trees adapt more easily to winter extremes than when planted farther apart, for example 20-30 feet, as in traditional planting. Planting shrubs around the base of each tree will also minimize temperature fluctuations.
September and October are very good months for planting new, young trees as they are already in dormancy yet there is still a month or two for the roots to settle in and benefit from the special relationship they have with the soil mycorrhizae. In Zone 5, we can still do new planting in November, but it is more risky for the plants, as both the plant and soil are further into dormancy and so less able to adapt and connect before spring. As always, adding mulch around the base of the tree is beneficial, but never against the tree itself as that will trap moisture and make the tree susceptible to disease.
We can make ourselves cozy inside this winter but let's also remember to do what we can to help prepare our plants and trees for the colder temperatures of winter!
Image by Ton op de Weegh