Do you I need to water trees, shrubs and grass in the winter? Aren’t plants dormant?
Yes and yes. Winters in Northern Colorado are often dry, warm and we experience drought. Plants, young trees, shrubs, and even lawns can become damaged without sufficient moisture. It should not be a surprise when lawns are drought stressed or even dead in areas after not receiving consistent moisture for over 6 months! 😳
Lawns going into winter that are drought stressed are more prone to desiccation. (Turning sprinkler systems off early and not watering supplementally while we are still in the 70’s-80’s during the day) can stress a lawn out. Spring 2022 we saw some of the worst green-ups in lawns across the Front Range because of desiccation. What is it? Desiccation occurs when turf is unprotected by snow cover and exposed to drying winds for long periods during the winter and into spring. Under these conditions, the turf can lose significant moisture, resulting in the death of the plant. Another definition is desiccation is extreme dryness which occurs when water in the plant is lost at a faster rate than water is replaced. Essentially, the grass plants are dried out to the point of being completely devoid of moisture. There is a huge difference between dormancy and desiccation. A common misconception is because grass is “dormant” during winter and early spring, it will be fine without consistent moisture for about 6 months. Name a plant besides cactus that can survive for 6 months with less than 2 inches of water total, which was the moisture amounts for Spring 2022 in Colorado – definitely not grass! 😳
We are seeing a lot of completely dead sections and/or a layer of desiccated grass with new growth coming out of it like the picture shown below. Some desiccated sections will recover however it takes more to recover from an illness than to prevent one! Same goes for your turf – best to follow good cultural practices and prevent desiccation before it occurs by watering monthly if we do not receive adequate moisture while irrigation systems are off.
According to the CSU extension, a good rule of thumb is if 4 weeks has elapsed without any significant moisture, then water when temps are above freezing and closer to midday so the water can soak in before the temperatures start to drop. This is important for young trees, shrubs and lawns because they don’t have moisture to sustain them through the dry months. Also, shrubs and lawns with south and west exposure will be drier since the sun here in Colorado can be intense and increase dryness and drought conditions.
Plants and trees won’t always die immediately without water but it can seriously weaken them. The CSU Extension notes, trees, shrubs and turf might initially return in the spring, but often are more susceptible to diseases and lawn damaging insects and die off in the hot summer months. Potential customers call and say, my lawn came back in the spring just fine and now it is really struggling. We have observed large scale mite damage in the past few years due to lack of moisture and warmer winters which is a perfect breeding ground for these very small insects.
A good guide is 10 gallons of water for each diameter inch of the tree. So a 3-inch diameter tree would receive 30 gallons of water. Turn on your hose super slow and let it trickle so it soaks in deeply and reduces runoff. Water your grass for at least 20 minutes by a hose end sprinkler from a spigot since irrigation systems are winterized. Set your lawn up for success by sustaining it through dry winter months, by giving it a drink if needed.
Learn More Here is a short video about watering trees in Winter from CSU – we would add lawns need it too! https://www.youtube.com/watch?v=xtl3-_Mw4o4&list=PLF923A9DD3BD61E42&index=28
Here is a good article about desiccation by CSU Professor Tony Koski https://csuhort.blogspot.com/2022/06/my-lawn-has-never-looked-this-bad-tony.html