Temperatures have been mild, the sun bright, and breezy this winter with very little precipitation. The metabolic rates of trees have slowed. However, those trees are alive. They are taking up water and expelling water vapor into the air; this process is called transpiration.
The soils are dry and water for roots to take up is limited. When trees don’t have enough water to support life, they need to make budget cuts to their system. These budget cuts include reducing the roots and branches.
As roots dry out in the soil and die, uptake of water from the soil is reduced. Reduced uptake of water into the tree causes “winter kill” of branches. Both these impacts have implications to the tree’s health and ability to produce energy the following spring. As this process gets repeated, it creates a downward health spiral which can lead to other complications such as insect attacks, fungal problems, bacterial infections, and other serious issues. The downward spiral can then become a death spiral. So how do we avoid this?
Winter Hydration
Water is the primary answer. Water is life for all living organisms and trees are no exception. Our Winter Hydration program involves injecting water and liquid organic matter under pressure using a probe into the root zones of trees to create and maintain pore spaces which absorb and retain water for plants to use. We inject kelp and yucca extracts to add organic matter into the soil. Humic acids, which help break down heavy clays, are also injected.
Homeowners are encouraged to do their own watering as well for maximum benefits. A simple lawn sprinkler and a hose are all that is needed. The areas under the canopies of trees should be watered for a couple to several hours, mimicking a good long rain. Winter Hydrations are done monthly. If the ground is frozen for most of the month, we will skip that month.
Anti-Desiccants
For evergreen trees and semi-evergreen plants, we can apply a waxy coating to help reduce moisture loss in needles and leaves. This application is called an Anti-Desiccant spray. The spray is a horticultural product designed to limit moisture loss but does not affect gas exchange. They are essentially a protective moisture blanket for the trees which helps prevent excessive moisture loss. Anti-desiccants are especially effective when soils are frozen and “free water” is limited for uptake. Anti-Desiccants are usually done every other month throughout the Winter.
Dormant Oils
Insect controls can be done organically in winter by applying horticultural oils; this application is called a Dormant Oil Spray. These super refined horticultural oils cover overwintering eggs, larvae, and adults. The thin layer of oil creates a physical barrier that clogs the insect’s spiracles, holes in the exoskeleton through which the insects’ breath, and causes them to suffocate and die. It is a mechanical type of modal action versus the systemic or internal modal action of chemical pesticides. Horticultural oils are also known to prevent insects from laying eggs on treated plants, providing another layer of protection. Studies have shown dormant oil applications may delay leave and flow bud opening in Spring, reducing spring frost injury. Dormant Oil Applications are completed once per winter.