We all know that plants and shrubs need water for photosynthesis to stay healthy, strong, and lush. However, watering your shrubs in winter can be challenging due to the high air humidity, ice, and frost formation. These conditions beg the question, “Is it necessary to water shrubs in winter?”
Shrubs should be watered in winter only when soil and air temperatures exceed 40°F (4.44°C). Watering shrubs in winter protects their roots from damage due to freezing and helps them store water for the dry summer months. You should ensure to wet the top 6 to 9 inches (15.24 to 22.86 cm) of soil.
In the rest of this article, I’ll discuss the amount of water your shrubs need in winter and how to water them. I’ll also discuss the factors you should consider when watering your shrubs in winter. Let’s get started!
How Much Water Do Shrubs Need in the Winter?
You might have heard the saying, “too much of anything is poisonous,” the same applies to watering your shrubs in winter. Check out my article about how much water is too much for shrubs.
Shrubs need between 5 to 18 gallons (18.93 to 68.14 liters) of water monthly in the winter. The specific amount of water you apply to your shrub in winter depends on the following:
- The size of the shrub: The taller the shrub, the more water it needs.
- The shrub’s age: Young shrubs need frequent watering with less water.
From the above demonstration, it’s clear that all shrubs, newly planted or old ones, must be watered in winter.
In the next section, I’ll cover how size and age affect the amount of water your shrub needs.
The Size of the Shrub
The ideal shrub size is between 2 to 33 feet (60.96 to 1,005.84 cm) tall.
According to the National Library of Medicine, larger shrubs have a greater total transpiration surface.
This means that they lose more water through transpiration than smaller shrubs. Consequently, they need more water to replenish that lost through transpiration.
Larger shrubs also have a more extensive root system, which helps them access more water from the soil.
On this note, larger shrubs, more than six feet (182.88 cm) tall, need 18 gallons (68.14 liters) of water monthly in winter.
On the other hand, smaller shrubs have lesser total transpiration surfaces. Therefore, they lose less water at any given time. Consequently, they need less water to replenish what they lose through transpiration.
As such, smaller shrubs, less than three feet (91.44 cm) tall, need only five gallons (18.93 liters) of water monthly in winter.
The Age of the Shrub
Younger shrubs have less extensive root systems and are not as drought-tolerant as older ones. Moreover, their root systems cant absorb a lot of water at once. This complicates watering such shrubs since they need more water – but the water should not be applied at once.
Newly planted shrubs need more water per month in winter, applied in different settings. As a rule of thumb, you should apply five gallons (18.93 liters) of water to your newly planted shrubs twice a month. Therefore, freshly planted shrubs need 10 gallons (37.85 liters) of water monthly in winter.
However, you may wonder what would happen if you decide to apply 10 gallons (37.85 liters) of water to your newly planted shrub in winter at once instead of five gallons (18.93 liters) twice.
Two things will happen:
- Your shrub’s roots will be waterlogged: Winter temperatures are very low. As a result, the vaporization process is very low. Therefore, the plant must absorb the water as fast as possible to prevent water logging. Young shrubs can’t absorb water fast due to their less extensive root systems, leading to water logging and, consequently, root rot and fungal infections.
- Frost/ice will form: The cold winter temperatures can convert the excessive water into frost or ice. When this happens, your shrub’s roots are exposed to winterkill due to the shear pressure from ice or frost.
On the other hand, older and established shrubs have more extensive root systems. These root systems are capable of absorbing a lot of water at once. This explains why you can apply 18 gallons (68.14 liters) of water monthly in the winter at once.
Expert Tip: You should apply deep watering to wet the top six to nine inches (15.24 to 22.86 cm) of soil around older shrubs once a month. Wetting this part of the soil helps ensure the plant has sufficient water to take it through the month.
How To Water Your Shrubs in the Winter
You can water your shrubs in the winter in two ways:
- Overhead watering with hoses or sprinklers.
- Root watering with soaker hoses (the most efficient way).
Overhead Watering
Overhead watering is the most common method of watering shrubs in winter. It’s simple; all you need is a water hose or sprinkler.
However, this method has several disadvantages:
- It wastes a lot of water due to evaporation.
- The force of the water can damage your plant’s leaves, especially if they’re still tender.
- It’s not as effective in getting water to the roots.
- It may expose the leaves to frost formation if the temperatures drop below the freezing point.
Root Watering
Root watering using soaker hoses is an efficient way of watering your shrubs in winter since they minimize evaporation and waste. Moreover, they gently deliver water to the roots without damaging the plant’s leaves.
Since the water is delivered directly to the roots, this method eliminates the risk of frost formation on your plant’s leaves.
When frost forms on your shrubs due to the cold temperatures (which can drop below the freezing point), the leaves experience extensive unnecessary pressure. Moreover, it reduces the surface area of leaves available for photosynthesis. Thus, the shrub suffers a lot and may become dormant to survive. This explains why you may find some shrubs with brown leaves in winter.
For efficient water delivery, lay the soaker hose along the rows if your shrubs are planted in a line. If they’re planted in a bed, lay the hose around the outer edge of the bed.
Make sure you turn on the water slowly to avoid damaging the roots with too much pressure. Moreover, keep an eye on the soil to ensure it’s wetting evenly. When done, turn off the water and remove the soaker hose.
Factors To Consider When Watering Shrubs in Winter
You must be cautious when watering your shrubs in winter to keep them alive. Here are the essential factors to consider:
Temperature
Never water your shrubs when air and soil temperatures drop below 40°F (4.44°C).
Soil freezes at temperatures below 40°F (4.44°C), meaning the water can’t soak into the ground. Additionally, the water on your plant’s leaves may freeze and cause damage when the temperature is extremely low.
It’s advisable to only water the shrubs when the temperature is above 40°F (4.44°C) so that by the time the water is ready to freeze, it will already have been absorbed into the soil. Furthermore, this prevents frost and ice formation on the leaves. I’ve written an in-depth guide about when it’s too cold to water your shrubs.
Frequency
Only water your shrubs when the soil is dry to the touch. This means you shouldn’t water them more than twice a month.
You can use a trowel or screwdriver to check the top four to six inches (10.16 to 15.24 cm) of soil to confirm if it’s dry to the touch.
You can reduce the watering frequency to every six weeks if you live in an area with high rainfall.
Amount of Water
Overwatering your shrubs in winter exposes them to frost, ice, root rot, and fungal infections.
You should water your shrubs based on their age and size. Young and small shrubs require a regular water supply in small quantities, while the mature and large ones can sustain more water at once.
It would help to consider the plant species since some are drought-resistant. Such plants don’t require much water, even in winter.
Time
Early in the morning is the right time to water your shrubs. If you water shrubs in the heat of the day, 40 percent of the water is lost due to evaporation.
On the other hand, watering in the late evening increases the chances of the water freezing due to the cold nighttime temperatures.
Conclusion
Watering your shrubs in winter is a must-do regardless of the size and age of the shrub. How much water you apply to your shrub depends on its age and size. The taller the shrub, the more the water, and vice versa.