OAKS, OAKS AND MORE OAKS (QUESTIONS - THAT IS!)

By Robin Stanley

UCCE/El Dorado Master Gardener

Q. I’ve heard that you shouldn’t plant plants that need a lot of water under oak trees but I have also seen oak trees growing in lawns that are irrigated. I love my oaks but want to add more flowers to my landscape. Do you have any suggestions?

A. Some of the oaks you might be seeing growing in lawns may have been grown in that environment since the oaks were young. This has allowed the oaks to adapt to their summer water over time and that’s what allows them to survive. This is not a typical situation, so if you are trying to landscape with mature oak trees, don’t think you can copy that scenario. There are native plants that can be successfully grown under and/near oaks because they require less water and don’t create the extensive root mass that typical grasses and groundcovers develop. While California oak experts generally recommend planting nothing under oaks, if you are going to plant some “approved” plants, you should take care to disturb the soil as little as possible and not plant closer than 4 feet from the trunk. That means that you should plant small plants that don’t require a lot of deep digging. One suggestion for planting near or under oaks is red flowering current; its berries add color and it doesn’t require much summer water. Coffeeberry can also be an attractive addition to your landscape. You might also consider some of the native sages or monkey flowers to see if they appeal to you. For spring color, daffodils are good.

Just remember, when selecting the plants, that you could never replace your majestic oaks within your lifetime. So take care and choose and plant wisely.

Q. I have a lot of dead branches on my black oak tree and wonder if it is OK to prune them off in the summer time, when it is easy to see them, or I should wait until the tree is dormant.

A. According to the oak experts in the UCCE handout, “LIVING AMONG THE OAKS”, “light pruning can be done at any time of the year. Heavy pruning, however, should be made during the dormant season.” For your deciduous black oaks, this dormant period would be in the winter but for evergreen trees, such as interior live oak, the dormant season is July and August. “The most important factor in pruning is to make all cuts correctly. Avoid leaving branch stubs and do not paint the cuts with tree seal.” Single copies of this handout are available at no cost to homeowners by calling 510-643-5429.

Q. I haven’t heard too much about Sudden Oak Death lately. Are we still safe from it in El Dorado County?

A. Researchers continue to study the Phytopthora ramorum pathogen to learn more about the spread and to try to develop broad-scale treatments. At this point, it has not spread to the central valley or foothills, probably because of the heat and dryness of our summers. Scientists continue to monitor for the disease throughout the United States (and the world) but for El Dorado County at this point, no news is good news. For more information about Sudden Oak Death, check out the website of the California Oak Mortality Task Force (http://www.suddenoakdeath.org/).