How to water your trees through a Salt Lake summer.

By Mike Wilson, ISA Certified Arborist (#UT-4612A) · Published July 4, 2026 · 6 min read

Every July I get the same call: a homeowner in Sandy or Holladay notices their maple's leaves are scorched brown at the edges, or a whole section of the canopy has gone crispy, and they assume the tree is dying or diseased. Nine times out of ten, it isn't sick. It's thirsty — and it's being watered exactly wrong.

Salt Lake County trees live in a high-desert climate that most of them didn't evolve for. Between the heat, the low humidity, and lawn irrigation that's tuned for grass instead of trees, established trees quietly run a water deficit all summer. Here's how to fix that.

Water deep and infrequent, not shallow and daily

The single biggest mistake I see is short, frequent watering. A lawn sprinkler that runs ten minutes a day keeps the top inch of soil damp, which is great for grass roots but useless for a mature tree. It actually trains tree roots to stay shallow, right where the soil dries out fastest and where they're most vulnerable in a drought.

Trees want the opposite: a long, slow soak that pushes water 12 to 18 inches down, then several dry days before the next one. That deep watering pulls roots downward, where the soil holds moisture far longer.

Rule of thumb: an established tree wants about 10 gallons of water per inch of trunk diameter, every 1–2 weeks in peak summer heat.

So a tree with a 10-inch trunk wants roughly 100 gallons in a single deep soak, not a splash every morning. Measure trunk diameter at about knee height (4.5 feet is the technical standard, but knee height is close enough for a garden estimate).

Water the drip line, not the trunk

The roots that actually absorb water aren't clustered against the trunk — they fan out to and beyond the drip line, the circle on the ground directly under the outer edge of the canopy. That's where you want the water going.

• Soaker hose: loop it in a spiral out toward the drip line and let it run low and slow for an hour or two.
• Slow-drip: a hose at a trickle, moved around the drip line every 20–30 minutes.
• Deep-root needle: useful for compacted clay soils common along the valley's benches.

Avoid piling water against the base of the trunk. Constantly wet bark invites rot and fungal problems at the root collar — the opposite of what you're after.

Young and newly planted trees are different

A tree planted in the last two or three years hasn't grown the wide root system that carries an established tree through dry spells. Those need water more often — roughly twice a week in summer heat — focused right on the original root ball as well as the surrounding soil. Keep it up until the tree has been in the ground through two full growing seasons.

Mulch does half the work for you

A 3–4 inch ring of wood-chip mulch over the root zone is the cheapest drought insurance there is. It slows evaporation, moderates soil temperature, and cuts down the watering you need to do. Two rules: keep it pulled back a few inches from the trunk (no "mulch volcanoes"), and spread it wide — out toward the drip line, not just a tidy little donut.

The drought-stress signs worth a closer look

Some summer leaf scorch is cosmetic. But a few signs mean a tree is under real stress and worth having looked at before it becomes a hazard:

• Leaves browning from the edges inward, wilting that doesn't recover overnight, or early fall color in July and August.
• Whole limbs leafing out sparsely or not at all while the rest of the canopy is full.
• Bark cracking, or dead twigs snapping off easily at the branch tips.

Chronic drought stress is also what opens the door to the borers and diseases that finish a tree off. A stressed tree is a target; a well-watered one defends itself.

Watering right won't save a tree that's already failing, but it prevents most of the summer decline I get called out for. Give your trees a deep drink, mulch the root zone, and they'll shrug off a Salt Lake July.