Portland summers are famously dry. After our wet winters and springs, July through September often brings weeks with little to no rain, putting stress on trees across the Eastside, West Hills, and everywhere in between. Preparing now helps your trees develop deeper roots, retain moisture, and stay strong through the heat.
At Harrity Tree Specialists, our ISA Certified Arborists have supported thousands of Portland-area landscapes through seasonal challenges. Here’s your practical checklist to help your trees thrive this summer.
1. Water Deeply and Infrequently
The #1 way to prepare trees for dry conditions is proper watering that encourages deep root growth. Shallow daily sprinkles do more harm than good by keeping roots near the surface.
Guidelines for Portland:
- Newly planted trees (first 2–3 years): 15–25 gallons per week, or more in extreme heat. Water 2–3 times weekly.
- Established trees: Deep soak once every 7–14 days, delivering the equivalent of 1–2 inches of water across the root zone.
- Water slowly at the drip line (outer edge of the canopy) and beyond, early morning or evening to reduce evaporation.
Pro tip: Use a soaker hose, tree watering bag, or slow hose trickle. Check soil moisture by digging 6–8 inches down—if it’s dry, it’s time to water.
Learn more about our Plant Health Care services
2. Apply or Refresh Mulch
Mulch is one of the best defenses against summer drought. It cools soil, reduces evaporation, suppresses weeds, and adds organic matter over time.
How to do it right:
- Apply 3–4 inches of organic wood chip mulch in a wide ring extending to the drip line.
- Keep a 2–3 inch buffer around the trunk to prevent rot and rodent damage.
- Refresh existing mulch now before the heat peaks.
3. Improve Soil Health
Portland’s clay-heavy soils compact easily and drain poorly in winter but dry out fast in summer. Healthy soil holds moisture better and supports stronger roots.
Consider a professional soil test to check for compaction, pH, and nutrient levels. Our team can recommend targeted amendments that improve water retention without over-fertilizing during dry months.
4. Prune Strategically
Light summer pruning can help by reducing canopy density and water demand, but avoid heavy cuts during peak heat. Focus on dead, damaged, or crossing branches. For best results, schedule structural work with certified pros.
5. Monitor for Drought Stress
Watch for early warning signs:
- Wilting or scorched leaf edges
- Premature leaf drop
- Smaller-than-normal leaves
- Cracks in the soil around the base
Act quickly when you see these—established trees are resilient, but early intervention prevents long-term damage.
6. Choose Drought-Tolerant Species for Future Planting
If you’re adding trees this year, select varieties well-suited to Portland’s Mediterranean-like summers, such as certain oaks, native pines, or drought-adapted maples. Our arborists can recommend the best options for your site.
Why Professional Help Makes a Difference
DIY care works for basic tasks, but a certified arborist can spot hidden issues, provide deep root watering systems, and create a custom summer care plan tailored to your property and tree species.
Ready to Protect Your Trees This Summer?
Don’t wait for the first heat wave. Harrity Tree Specialists offers expert assessments, watering guidance, mulching, and full plant health care programs designed for Portland’s unique climate.
Contact us today for a free consultation and give your trees the best chance to beat the dry summer.
🌳 Healthy trees start with smart preparation.
Additional Resources:
- Portland Parks & Recreation Tree Establishment Care
- Oregon State University Extension: Selecting, Planting and Caring for New Trees
- Pacific Northwest ISA Chapter for local arborist standards
Follow our blog for more seasonal tips and trust Harrity Tree Specialists—Portland’s certified arborists since 1992. Questions about your trees? We’re here to help!
