If you’ve lived in Oregon for a while, you’re probably used to both trees and hot, dry summers. “I don’t water the older trees in my yard,” you may be thinking to yourself, “so do my new trees really need water?”

First, if you planted a new tree within the past few years, thank you! Now, let’s help make sure that tree survives and thrives.

To understand the importance of watering young trees during the summer, it’s helpful to know a couple of things about how trees work. Trees do most of their growing during spring and summer, and like any growing creature, trees need food. Through a process called photosynthesis, trees combine water and carbon dioxide into food for themselves (and oxygen for us to breathe; thanks, trees!) When there isn’t enough water, trees can’t make the food they need to survive.  As you can see, water is at the root of everything a tree does!

What about those older trees in your yard or along the street? Mature trees rely on extensive root systems to collect the water they need, even when it hasn’t rained in a while. Soil is like a sponge because it stores water that soaks into it. Mature trees can stretch their roots out for hundreds of feet around them and draw on water stored in the soil. Newly planted trees don’t have the same root systems in place yet, so they have access to much less water.

Your tree will need a few years to recover from getting transplanted and to grow enough roots to get the water it needs. In the meantime, weekly watering through the hottest, driest months, will help your trees grow, build up energy reserves, and fight off pests and diseases.

Here’s how you can help your tree get the water it needs this summer:

DO water at least 10 gallons per week during May-September. Give the tree all 10 gallons at once. Hose or bucket? It’s up to you!

DON’T rely on a sprinkler to water your tree. Sprinklers only wet the surface and do not provide the deep water a tree needs. Sprinklers also add moisture to the air, which may encourage some types of pathogens.

Of course, there can be too much of a good thing. Before watering, use a hand trowel to dig down a few inches within a foot or two of your newly planted tree. If the soil is still wet, there’s no need to water.

Visit the Environmental Services Tree Program website to learn more about tree care and stewardship opportunities.