How often should I water my mature native or drought-tolerant trees?
Trees that have matured in non-turf landscapes adapt the easiest, especially drought tolerant species. Native trees, such as our California oaks, need MUCH less water than most non-native trees. California oaks may only need one or two deep waterings over the summer, but no water within 1 to 2 feet from the trunk. They absolutely need the soil to dry out for a month or two before more water, if any, needs to be reapplied.
Non-natives and higher water need trees such as birch and redwoods will appreciate a deep soak weekly or every other week depending on the heat of summer.
How is watering trees different than watering my lawn?
Your lawn sits on the surface of the ground and has shallow roots. It needs watering a few times a week, usually with a sprinkler. Trees need to be watered less frequently, but with deeper soaking – because their roots grow deep in the earth – the majority of tree roots are 1½ -3 feet deep. Lawn irrigation does not water trees effectively. It generally reaches only the first few inches of soil, encouraging weak surface roots to grow.
How to Keep your Trees Healthy
- Deeply and slowly water mature trees 1 – 2 times per month with a simple soaker hose or drip system toward the edge of the tree canopy – NOT at the base of the tree. Use a Hose Faucet Timer (found at hardware stores) to prevent overwatering.
- Young trees need 5 gallons of water 2 – 4 times per week. Create a small watering basin with a berm of dirt.
- Shower with a bucket and use that water for your trees as long as it is free of non-biodegradable soaps or shampoos.
- Do not over-prune trees during drought. Too much pruning and drought both stress your trees.
- Mulch, Mulch, MULCH! 4 – 6 inches of mulch helps retain moisture, reducing water needs and protecting your trees.
