As temperatures rise, here are a few simple tips to ensure your tree grows and thrives. 

How often should I water my tree? 

Just like people, it’s important for trees to stay hydrated in the summer heat. But before you run out and grab the hose, there are a couple factors to consider! Tree species and age will determine how much and how often you should water your tree. Young trees (tree ages 1-3 years after planting) will need to be watered more frequently. Most established trees (trees 3+ years after planting) need deep watering once a month when the weather is dry—regular lawn sprinklers won’t water deeply enough to reach a tree’s root.  Be sure to keep an eye out for signs of heat stress in your trees. Wilting leaves or drooping branches, crispy brown on yellow spots on leaves, or curling leaves are tell-tale signs that your tree may be experiencing summer heat stress and need more water. Download our printable guide for water wise tree care to learn how to care for the leafy friends in your yard. 

How to water young trees (1-3 years after planting) 

Trees younger than five years old are most at risk during the hot summer months. In general, young trees will need water one to three times per week for the first three years after planting. The easiest way to water young trees? Drill a small 1/8″ hole near the bottom of a 5-gallon bucket. Place a piece of duct tape over the hole, fill the bucket with water, place it near the root ball, and remove the tape to allow water to slowly drain into the soil (see Figure 1). You can also use a small soaker hose, drip tubing or emitters, or a hose sprinkler on a very low setting. Avoid spraying the trunk and expand the watering zone outward as the tree grows.  If you are in need of a watering bucket, we have some available on our yard. Check our website for yard hours or call ahead to coordinate pickup. 

How to water mature trees (3+ years after planting) 

Established and mature trees will need water about once per month in dry months (note: native trees like blue oaks will not need summer water in non-drought years). To water a mature tree, slowly soak the tree’s drip line until water reaches 12-18 inches below the surface (see Figure 2). Don’t water close to the trunk. You can use a soaker hose, a hose sprinkler on a low setting, or drop tubing or emitters to do this.

For detailed watering tips, videos, and more, visit sactree.org/water or sign up for our next Smart Irrigation watering workshop on June 8 (9:00 a.m.-10:30 a.m.).

Save water with mulch 

Adding a natural wood chip mulch protects roots from extreme temperatures, keeps moisture in the soil, and saves you money by preventing water runoff. Wood chip mulch around your tree reduces competition for water with weeds and grass and sets the soil up to retain moisture during the hot season.  

Before you apply your mulch, be sure to pull any grass and weeds around the base of your tree; you’ll want to place the wood chips directly on top of the soil. Around a young tree, wood chips should be placed in a four-foot circle around the tree, four inches from the trunk, and six inches deep – a big, thick ring shaped like a doughnut (see Figure 3). Around mature trees, apply wood chips on top of the soil in as large an area as possible in your yard. You can find additional mulching tips at sactree.org/mulch. 

If you only need a small amount of wood mulch, you can pick it up free of charge from SMUD at 6100 Folsom Blvd. Call 916-732-5900 to check availability and hours (remember to bring your own shovel/pitchfork, buckets, tarp, etc.). Pick up hours are typically Monday-Friday from 9 a.m. to 4 p.m. One young tree needs two or three 5-gallon buckets of wood chips. You can also contact a local tree care company or ChipDrop to ask about delivery of an entire truckload. 

Why is my tree so skinny? 

Many young trees grow taller during their first few years of establishment, and often don’t produce many side branches. But there’s no need to fret: a tall, skinny tree is right on track to grow a wide canopy. It’s healthy for a tree to develop height first before growing side branches. Young trees don’t have the same “lollipop” shape as they will when they’re mature. You can expect your tree to begin taking its more robust shape in about year. 

Skip the summer pruning 

No need to prune your trees this summer except to remove broken or diseased branches. Pruning is best done in winter when the trees are not actively growing. Pruning tips and tutorials at sactree.org/pruning. 

Why is there sticky sap under my tree? 

Have you noticed  gooey, sticky dots on your tree’s leaves or sappy sidewalks? If so, it’s a sign that aphids are in your trees. During the warm weather, sap-sucking aphid populations increase dramatically. Tiny woolly aphids that appear bluish or white chew on leaves (some of their favorites to munch on are hackberries, red oaks, and crape myrtles) and excrete copious amounts of a sticky waste known as honeydew. Although aphids won’t cause much damage when the populations are small, heavy infestations can deform leaves and deplete resources from the tree. When aphids cause the edges of leaves to curl, they will hide inside, making it harder to treat the issue. While trees seldom die from aphids alone, they can make an unattractive mess and stress your trees. Luckily, there are options for you to control the aphid population in your yard. 

• For smaller trees, you can use a strong spray of water to knock the aphids to the ground. Aphids are relatively weak and have a hard time climbing back onto the plant, especially if the water pressure is strong enough. If you can get them off the tree, they likely won’t be able to get back on there. Aphids reproduce quickly so knocking them your tree will also interfere with their life cycle and the population growth rate. 
• Look for ants around your tree. Ants will protect aphids because they like to eat the honeydew they produce. If you look closely at your tree’s trunk and notice ants going in and out of the tree, try wrapping the trunk with a bit of tape, sticky-side out, to prevent more from getting in the tree.  
• If your aphid infestation is heavy or becomes an annual, untenable issue, you may need to treat your tree with a pesticide. Plan to treat your trees in the late winter to prevent an aphid infestation the following year. There are some natural pesticides available for use but hire a certified arborist to discuss whether they are feasible for your tree. They may suggest stronger solutions to eradicate the pests. 

Alternatively, you might consider planting tree species that aren’t as susceptible to aphids. The Tree Foundation can help you select the best trees for your yard with a free landscape assessment for SMUD customers through our Sacramento Shade program. To learn more about the program or to fill out an application, visit sactree.org/freetrees. 

Other resources

We have many blog articles, video tutorials, and other resources online that may answer your question. Visit sactree.org/treecare to find our best tips for growing healthy trees.