Knowing how to water trees in Central Texas is one of the most unexpectedly complex issues that plagues homeowners across Austin. There are so many misconceptions and conflicting professional opinions about it. Even for me, a Certified Arborist with years of planting experience, the answers took time to find and quite a bit of trial and error.
For years, I’ve been on a quest to find the right answers. I’ve spoken with growers, suppliers, other arborists, and every industry expert who would talk to me. The consensus is that while it is a nuanced topic, you can follow key principles to keep your trees healthy and thriving.
Need expert help with your trees? Our ISA Certified Arborists are here to help. Call us at 512-729-8733 or contact us online.
Here is a straightforward, actionable guide to watering newly planted trees. But first:
How Long Does it Take Newly Planted Trees to Establish?
Tree establishment time depends on the trunk’s caliper (the diameter of the trunk measured 6-12 inches above the soil line): it generally takes one year per inch.
A 1-inch caliper tree will likely take 1 to 1.5 years to establish, while a 2-inch caliper tree can take 2 or more years. This guide applies to watering during the establishment phase of your trees.
Established trees need less frequent deep watering than newly planted trees (only every few weeks, or just during drought) applied over a wide area extending to their drip line (canopy edge), because their roots have spread out and can store more water.
The Golden Rules of Tree Watering
1. Water Deeply and Slowly
Every time you water a tree, the goal is to thoroughly saturate the soil to a depth of at least 2 to 3 feet and at least as wide as the current “tree well” (the area directly beneath the canopy or mulched ring). Very slow and deep watering is always recommended to ensure the water penetrates the soil rather than running off.
2. Aim for 10 Gallons Per Caliper Inch Per Watering
A reliable rule of thumb for how much water to apply is: 10 gallons of water per inch of trunk caliper (the diameter of the trunk measured 6-12 inches above the soil line) per watering session.
3. Check the Soil Moisture (The Metal Rod Test)
Don’t guess! Even with this guide you need to check on your trees. Use a simple tool to know exactly when to water next:
- Use a thin metal rod (3/8″ re-bar or bamboo is ideal).
- Push it down into the soil near the edge of the tree well.
- If it inserts easily to a depth of 18″, soil moisture is sufficient.
- If it’s hard to insert or won’t go in, it’s time to increase your watering frequency.
Can Lawn Irrigation Properly Water Your Trees?
A common misconception is that your lawn’s sprinkler system provides enough water for your trees. Wrong!
Sprinklers usually provide shallow, frequent watering that promotes shallow root growth, making trees less resilient to drought and heat. Trees need deep, infrequent watering to establish strong, deep root systems.
Watering Schedules: Seasonal Adjustments
You’ll need to make adjustments throughout the year to accommodate seasonal changes and specific weather conditions.
Watering Newly Planted Trees (The First 2-3 Months)
New trees are the most vulnerable.
- Initial Deep Soak: Water immediately after planting to deeply saturate the roots and help re-compact the soil around the root ball.
- Initial Frequency:
- For fall/winter plantings: Water every day for the first 3 days.
- For summer plantings (when heat and transplant shock are highest): Water every day for the first 6–8 days.
After initial watering is complete, back your frequency off according to the appropriate season. If you’re wondering when is it best to plant trees in Austin, it’s in the fall or winter when trees are dormant (as long as they’re in the ground at least 6 weeks before a major freeze.)
| Season | Low Water Needs (Native) | Medium Water Needs | High Water Needs |
|---|---|---|---|
| Fall | Once a week | Twice a week | Twice a week |
| Summer | 2-3 times a week | 3-4 times a week | 4-5 times a week |
| Spring | Once a week | Twice a week | Twice a week |
| Winter | Once a week | Once a Week | Once a Week |
Common Tree Water Needs:
Low: Cedar Elm, Chinquapin Oak, Live Oak, Lacey Oak, Red Oak, Mountain Laurel, Redbud
Medium: Bur Oak, Cherry Laurel, Crape Myrtle, Yaupon
High: Bald Cypress, Pecan, Sycamore
Adjusting for Extreme Heat
Central Texas summers demand extra attention:
- If temperatures exceed 100ºF: Add one additional watering session per week for all varieties.
- If temperatures exceed 110ºF: Provide another additional watering per week.
Adjusting for Rain
For periods of heavy rain (1/2″ or more), adjust accordingly by possibly skipping your next scheduled watering session. Use your metal rod test to confirm!
How to Water: Tools and Techniques
Ditch the hose-in-hand method and automate your system.
- The Hand-Watering Trap: Relying on hand-watering sounds simple, but very few people can keep up with it. Life gets busy, days get missed, and that inconsistency is what kills most young trees.
- Install Timers: Set up automatic watering systems using timers. You can install professional systems, or use workarounds like attaching a simple hose-end timer to a soaker hose or drip line with emitters.
- Use Drip Systems: Drip irrigation is efficient and delivers water directly to the roots slowly.
- Measure Your System’s Output: Place your drip line or soaker hose into a large bucket and run it for one minute. Measure how much water you collected. From there, do the math to figure out how long you’ll need to run the system to deliver the proper amount — about 10 gallons per inch of trunk diameter. It should take at least an hour for your system to deliver a deep soak. Remember: slow, deep watering is the goal. Fast watering just runs off the surface and never reaches the roots.
Need help setting up an irrigation system for your trees? Our team can design and install professional tree watering systems tailored to your landscape. Learn more about our tree planting and healthcare services.
Troubleshooting and When to Call an Arborist
It is normal for new plants to shed a few leaves or appear slightly wilted while they acclimate. This is “transplant shock” and is common, especially in summer months. After a few months, the tree should return to normal health.
Pay attention to soil moisture levels. If the soil dries out quickly, increase your watering frequency. If the soil remains consistently wet, wait until it dries before watering again. To improve poor soil, consider adding a soil conditioner.
Check on your trees! Keep an eye on them. Early detection of problems is critical.
Concerned about your tree’s health? Our ISA Certified Arborists can assess your trees and provide expert care recommendations. Contact us today for a professional consultation.
Article Written By:
Eric Wilder
Owner, Wilder Tree Company
ISA Certified Arborist TX-5234A
Oak Wilt Qualified #771
Member ISA Texas Chapter