Thinking about a water wise landscape or new patio? Don't forget about your trees
by Stephanie Robinson
July 9, 2020
With rising temperatures and unpredictable rainfall in the last decade, many Sacramentans converted their lawns to water wise landscapes. While we fully support these lawn conversions, they can be stressful on your trees.
Mature trees are worth the effort to plan around and protect - our communities depend on the health, environmental, and economic benefits they provide. Once they are lost, it will take decades to replace them, but some initial planning could save your tree's life.
Initial signs of distress such as wilting can resemble drought stress, but other signs can appear over a year later - dieback in outer branches, susceptibility to pests and disease, and even death. Here are some tips to keep your trees healthy during landscape changes:
Consult a certified arborist
Hire an arborist as if your tree's life depends on it. It would be such a shame to install a shade-loving landscape that leads to the death of a mature tree, and subsequently all of the other landscaping that depended on its shade! While master gardeners, permaculture designers, and landscape architects are experts in their own fields, they often do not see the impact of their installations on trees since damage can take years to show. Get an opinion from a certified arborist to ensure that your trees will not be harmed.
Protect tree roots
Any disturbance to the soil under the canopy - such as grading, adding soil, digging, or hardscape installation - can damage tree roots. Trees depend on their roots to anchor themselves in the ground and also to absorb water and nutrients. Roots can extend beyond the canopy, so take special care when working near trees and consider alternatives such as rerouting driveways/pathways to avoid the root zone or installing noninvasive permeable pathways. Hardscape and impermeable, compacted pathways in the root zone can harm the tree over time, preventing roots from accessing the water and oxygen they need to survive.
Maintain the same soil moisture
While trees can be one of the most water wise plants in your landscape, mature trees do not respond well to sudden changes in watering. Switching from lawn sprinklers to more efficient types of irrigation is great, but make sure the trees receive approximately the same amount of water throughout the space under their canopies, and choose plants that will thrive with these same water requirements. An increasingly common feature of water wise landscapes is a rain garden, which conserves rainwater but can drown tree roots. An arborist can tell you if your irrigation and water harvesting plans will impact your trees.
Good news - the best mulch for your tree is usually free of charge! Cut costs and help your trees by picking up smaller amounts of wood chips from SMUD, or contact a local tree service to ask about delivery of an entire truckload. Landscaping materials like decomposed granite and rocks are not only expensive, they can be very harmful to trees. They do not provide any of the nutritive, insulating, or water saving benefits of wood chip mulch, and instead they compact the soil and retain heat near tree roots.
Learn the best ways to water your trees
Last month, we teamed up with the City of Sacramento Department of Utilities to offer a webinar on smart irrigation for your trees. If you missed, it you can still watch the recording here.
For answers to your questions, call us at (916) 924-8733 or send photos to firstname.lastname@example.org to get advice for your trees.