If you live in an area that frequently experiences long, hot summers and extreme heat and drought, you’ll want to have a plan for how to take care of your trees during a drought.
We’ll walk you through everything you need to know about giving your trees some TLC during prolonged drought, including watering methods, mulching, and how frequently to prune. We’ll even discuss what you can do to prepare before a drought and how to spot the signs of drought stress in your trees.
In this article, we’ll cover:
- How to Take Care of Your Trees in a Drought
- Signs Your Tree is Suffering From Drought
- How to Help Your Trees Recover From Drought Damage
- Caring for Young vs. Mature Trees During a Drought
- FAQ about Tree Care During Drought
How to Take Care of Your Trees in a Drought
If you want your trees to make it through the heat of summer, there are a few things you can do.
Watering
In times of drought, make sure your trees get enough water beyond the dripline. A dripline is the outermost fringe of the tree’s canopy, where water drips onto the ground. Most trees do not have tap roots, and their roots grow well beyond the canopy. In heavy clay soil, roots grow even farther horizontally and might be wider than the dripline. Because of this, watering, fertilizing, and mulching directly at the base of your trees does not provide them with the nourishment they need.
Since a large percentage of tree roots are in the top 12 inches of soil, make sure the moisture reaches 12-18 inches deep. It would be a good idea to invest in a soaker hose or a sprinkler system.
You can always install a water-efficient irrigation system such as drip irrigation. You might even consider investing in a weather-based irrigation controller that will automatically adjust watering time and frequency based on rain, wind, soil moisture, and the rate of evaporation. Do not use saline water for irrigation as it will make drought conditions worse.
Mulching
Mulch is great for your trees during a drought because mulch helps your trees retain moisture, keep the soil cool and reduce evaporation. You should layer 4 inches of mulch between each watering session and keep the mulch at least 6 inches away from your tree trunks
to prevent rot.
Using organic mulch like bark chips or pine needles will improve the soil quality and prevent pesky weeds.
Avoid using stones around your tree since they will increase the temperature around your trees. Do not use fertilizer during or immediately after a drought since tree roots are susceptible to root burn from the salts in fertilizers when there is a drought.
Since they decompose, improving soil structure and increasing soil fertility, it’s recommended that you use organic mulches, such as:
- Wood chips
- Pine needles
- Hardwood bark
- Softwood bark
- Cocoa hulls
- Leaves
- Compost mixes
Pruning
Properly pruning tree branches year-round will help your trees withstand dry weather and improve their structure and stability. It’s important to maintain proper pruning by removing the broken, dead, or diseased branches that can weaken the health of your trees.
However, ONLY prune away problem branches during a drought. Avoid heavy pruning during a drought until the conditions improve. When trees are stressed during a drought, they are more susceptible to disease and insects, and if not done sparingly, pruning can increase the risk.
Signs Your Tree is Suffering from Drought
Drought Stress in Leaves
Drought stress weakens the tree and paves the way for diseases or insect infestations. Leaves will wilt, curl, or turn yellow when they are suffering from drought stress. Deciduous trees will have brown edges or browning between veins, while evergreen needles will turn yellow, red, purple, or brown.
Prolonged droughts will cause new leaves to be unusually small, and growth will slow and nearly halt, causing the tree canopy to appear sparse and thin.
Drought Damage to Bark
During prolonged droughts, trees might develop cracks in the bark, especially in thin-barked trees. Furthermore, trees will become more susceptible to pests like borers, mites, and fungal diseases.
They also will have difficulty closing and healing wounds from insects, bark damage, or pruning. Sunken, grayish cankers, root rot, and wood rot are more likely to occur because of drought stress and can be spread to other trees.
Drought Damage to Branches
Your tree branches may show signs of dying along the top or outer tips during prolonged drought. Stems will die from the outer canopy inward if they are unable to gather nutrients. You will need to cut away dead branches so that they do not take vital energy away from living parts of the tree.
How to Help Your Trees Recover From Drought Damage
Helping your trees recover from drought is the same as preparing them beforehand: proper mulching, watering, and pruning. However, there are some extra things you can try if you aren’t satisfied with your results.
Root Stimulants
Root stimulants are available in powders, liquids, or gels and are used to ensure rapid root development. Root stimulants applied to the soil around trees can help enhance root growth. These materials have been run through several tests with promising results for improving tree health.
Root Aeration
Aerating and loosening compacted soils with compressed air while mixing in compost will benefit root growth and the soil’s capacity for holding water.
Growth-Regulating Hormones
Growth-regulating hormones help provide benefits for trees recovering from drought damage. These hormones reallocate energy to root growth to rebalance the tree.
The five major types of plant hormones are:
- Auxins
- Cytokinins
- Gibberellins
- Ethylene
- Abscisic acid
Insect Damage Control
Drought can result in increased pest activity from damaging insects such as:
- Invasive Shot Hole Borer: An exotic ambrosia (a symbiotic fungus) beetle that attacks healthy and drought-stressed trees.They attack the main stem and larger branches of trees, and leave a tiny, perfectly round entry holes.
- Pine Bark Beetle: Infests high numbers of conifers and cause extensive vascular injury and tree death. Symptoms of a pine bark beetle infestation includes pitch tubes, reddish boring dust, exit holes, and yellowing foliage.
- Spongy Moth: During dry weather, the parasitic fungi and viruses that keep spongy moths at bay are suppressed, allowing the larvae to escape and defoliate trees. Repeated attacks may kill trees or severely weaken them, exposing them to more diseases and insects.
Treatments that can help reduce insect damage include:
- Injections: Soil and trunk injections are absorbed by the tree and control pests. These methods are used by professional applicators and arborists, and some can be bought at your local garden center.
- Sprays: It’s recommended that you use eco-friendly sprays to treat you trees. You can find these at the garden center of your local hardware store.
- Removal by hand: The most time consuming method is to simply remove cocoons, and egg masses by hand.
Caring for Young vs. Mature Trees During a Drought
Young Trees
It’s best not to plant young trees during the heat of summer. During a drought, young trees should be given 15-20 gallons of water one to two times a week. You should also create a 3-4 foot wide basin around the tree to hold water.
Mature Trees
Mature trees can withstand dry conditions better than young trees and only need to be watered once or twice a month. You should water until the moisture soaks 18 inches beneath the topsoil. You can use a soil probe to determine how far the water has soaked through. Be sure to water past the dripline and not close to the trunk.
FAQ About Tree Care During Drought
Since weeds will be mostly dormant during a drought, applying herbicides is a waste of money. Wait until the lawn (and weeds) are actively growing before applying herbicides.
Most established trees can survive without photosynthesizing for up to a year. Trees experiencing extreme drought stress will enter their winter dormancy state much earlier, and a prolonged drought can have a significant effect on your lawn by creating a cycle of longer periods of dormancy and shorter intervening periods to prepare for it.
The trees you should prioritize watering are the ones most vulnerable to dry weather and harsh conditions. That means young or newly planted trees, trees growing within a restricted root zone (when plants are installed in a place that will eventually restrict their root growth), and trees that have recently received a root injury or have a damaged root system.
When to Hire a Landscaping Pro
If you’re not confident in your ability to take care of your trees during the hot summer months, or just would just rather be inside with a popsicle or iced teas, then you might be happier hiring a reliable landscaping pro instead.
If you need someone experienced to handle all of your tree, shrub, and lawn maintenance needs, check out Lawnstarter’s extensive list of landscaping contractors in your area.
Main photo credit: Famartin | Wikimedia
