Protecting Your Plants from Winter Desiccation

As we have been out and about in Landscapes this winter moving snow around we have started to notice quite a bit of winter damage in evergreen trees and shrubs. It is likely there will be elevated levels of this type of damage that appears this spring due to the drought that occurred last fall/early winter. Many areas are still in drought conditions according to the USDA drought monitor.

Understanding Winter Desiccation in Shrubs: Causes, Effects, and Recovery

Winter can be a magical time for nature, with frost-dusted branches, quiet, snow-covered landscapes, and a sense of stillness. However, for many plants, especially shrubs, this season can bring more than just aesthetic beauty—it can bring stress. One of the most common and damaging winter conditions affecting shrubs is winter desiccation. Understanding what this phenomenon is, how it affects plants, and how to prevent it can help keep your landscape healthy throughout the colder months.

What Is Winter Desiccation?

Winter desiccation occurs when a plant loses moisture faster than it can absorb it, especially during the winter months when water uptake by plant roots is limited. During this time, the plant's leaves or needles (in the case of evergreen shrubs) dry out. Desiccation is typically caused by a combination of environmental factors, including dry winds, low humidity, and freezing temperatures. While shrubs are usually dormant during winter, they can still lose water through transpiration, which is the process where moisture is lost through their leaves or stems.

How Does Winter Desiccation Affect Shrubs?

Winter desiccation can lead to visible damage that ranges from mild to severe. Some of the common symptoms include:

• Brown, crispy leaves or needles: This is perhaps the most noticeable sign, especially in evergreen shrubs. The leaves may appear scorched, dry, and brittle.
• Dead or damaged twigs and branches: If desiccation is severe, it can kill the tender growth at the tips of branches, resulting in dieback.
• Overall stunted growth or weakness in spring: Shrubs affected by winter desiccation may fail to bounce back properly in the spring, showing signs of slow or poor growth. This can leave them vulnerable to further stress and pests.
• Wilted or curled foliage: Some shrubs may exhibit wilting or curling as a way to conserve moisture, signaling a lack of hydration.

Why Does Winter Desiccation Happen?

Several environmental factors come together to create the ideal conditions for winter desiccation:

• Dry Winds: Cold, dry winds can strip moisture from plant tissues more rapidly than the plant can replenish it. This is especially common in areas with high wind exposure, such as coastal regions or open fields.
• Frozen Ground: When the ground freezes, plant roots can no longer absorb water. Although the plant may still be receiving sunlight and engaging in some level of photosynthesis, it can't take up enough moisture to keep the plant hydrated.
• Sunshine and Temperature Fluctuations: Winter days can bring bright sunshine that causes evaporation, especially on south-facing slopes or areas that are exposed to full sun. If temperatures fluctuate and the plant thaws during the day but refreezes at night, it can create a cycle of moisture loss and damage.
• Evergreen Shrubs: While deciduous shrubs lose their leaves in the winter, evergreen shrubs retain their foliage, which can continue to lose moisture throughout the winter months. This makes evergreens particularly vulnerable to desiccation, as their leaves or needles still have access to sunlight.

How to Help Shrubs Recover from Winter Desiccation in Spring

While winter desiccation can be a stressful condition for shrubs, the good news is that with proper care, many plants can recover in the spring. After the cold winter months, it's important to assess the damage and take steps to help your shrubs bounce back and regain their health. Here's how you can support your shrubs as they recover from winter desiccation in the spring.

1. Prune Dead or Damaged Growth: In early spring, take a close look at your shrubs and trim off any dead or severely damaged branches. Deadwood, which may appear brown, brittle, or completely dry, should be removed to encourage new growth and prevent disease. However, be careful not to prune too aggressively—only cut back the areas that are clearly damaged or dead. Light pruning can help your shrubs conserve energy and focus on healthy, new growth.
2. Water Deeply and Regularly: One of the most important things you can do to help your shrubs recover is to provide them with plenty of water. As temperatures rise and the ground begins to thaw, ensure that your shrubs receive consistent, deep watering. This will help rehydrate them and support the recovery of their roots. Be sure to water early in the morning or late in the day to avoid excessive evaporation. Avoid over-watering, however, as this can lead to root rot. The goal is to keep the soil consistently moist but not soggy.
3. Bio Stimulant Application: Once you’ve pruned and the shrub begins showing signs of new growth, you can consider applying a bio-stimulant fertilizer. This will give your shrub the nutrients it needs to recover fully and has beneficial stimulants, fungi and bacteria that help with root development, nutrient availability, salt remediation and gives a boost to the plants natural disease fighting processes. Contact CMS to see how our bio stimulant mix can help your plants!
4. Mulch Around the Base: Applying a fresh layer of mulch in the spring can help retain moisture in the soil, regulate temperature fluctuations, and prevent weed growth. Mulch acts as an insulating layer, which is particularly important if you’re in a region that still experiences late-season frosts. Aim for about 2 to 3 inches of mulch, being careful not to pile it up directly against the trunk of the shrub, as this can lead to rot. Mulching also prevents the soil from drying out too quickly, which can be especially helpful for shrubs that were stressed during the winter.
5. Monitor for Pests and Disease: Winter desiccation weakens shrubs, making them more vulnerable to pests and diseases. In the spring, keep an eye out for signs of pest activity or fungal infections. Aphids, scale insects, and mites are common culprits that could damage your shrubs further. Additionally, fungal diseases like powdery mildew or root rot may take advantage of stressed plants. If you are not sure what to look for our Certified Arborist will be happy to do an evaluation for you, or sign up for our tree and shrub program that proactively tackles these issues!
6. Be Patient and Monitor Growth: Spring recovery after winter desiccation can be slow, and your shrubs may not fully bounce back immediately. Be patient and continue to monitor their progress over the coming weeks. Check for any new growth and observe how the shrub responds to watering and treatments. If new growth is appearing healthy, this is a good sign that the shrub is recovering. If there’s little or no new growth, it might indicate that the shrub needs further care, or it may not survive the winter’s stress.
7. Consider Replanting if Necessary: In cases where the winter desiccation was severe and your shrub shows little recovery despite your best efforts, you may need to consider replanting. While it's always tough to lose a plant, sometimes starting fresh with a new shrub that is better suited to your climate or location might be the best course of action.

Conclusion

Helping your shrubs recover from winter desiccation in spring requires a combination of patience and proactive care. By pruning dead growth, ensuring proper hydration, applying bio-stimulants, and providing protection from pests, you can give your shrubs the best chance of bouncing back from winter stress. With the right support, most shrubs can emerge from the winter months healthy, vibrant, and ready for the growing season ahead.