Last month, Buzz contributor Emina Darakjy introduced Buzz readers to the Cork Oak tree. Her story prompted Buzz reader K. Mulligan to ask when an oak tree should be trimmed, if at all. In 2011, the Ridgewood Wilton neighborhood planted a California Live Oak in the traffic island at the corner of Wilton Place/Wilton Drive/Second Street. The tree has been nicely maintained by the neighborhood, but was never pruned. Her question — “how to do you know if an oak should be pruned at some point?”
We took some photos of the Coastal Live Oak and sent them to Emina. Below is her answer, lightly edited. Please feel free to email at [email protected] us if you have any tree questions for Emina!
“The oak tree looks beautiful and very healthy. Considering that nothing was ever done to it since it was planted, it grew very straight.
Oaks in general do not require much maintenance and when pruning is needed it is best to do it in the winter months or early spring, between November and March. Oak trees can be killed if pruned heavily or topped, which is the worst thing to do to any tree species. Unfortunately there are many tree trimming companies who leave business cards on people’s doors and the first line on the card or flyer says “We do topping.” Never hire such a company.
The Quercus agrifolia – coast live oak, also known as the California live oak grows between 30- to 60-feet tall and its crown can reach an even wider spread, it is also very drought tolerant and will not tolerate regular watering during the summer months.
Looking at the photos, this tree can benefit from some pruning to open up the canopy a bit, it looks too dense. A light pruning (no more than 10%) can also raise any low branches that might reach someone standing in the triangle. It is also a very good idea to always make sure none of the branches are hiding any traffic signs. You do not want someone suing either the city or the homeowners’ association in case of an accident saying the sign was not clearly visible!
This tree is going to continue to grow taller and wider and may hang over both sides of the triangle which is a very good thing. When that happens make sure the canopy is raised for traffic clearance. You do not want a truck to hit a large branch causing big damage to the tree where it might need to be cut down.”
Congratulations and thanks to the residents of Ridgewood-Wilton neighborhood for planting and maintaining this wonderful oak tree for all of us to enjoy! Not only are these amazing trees adapted to our climate, they are a keystone species that supports a great deal of wildlife. And best of all, they require very little assistance from us!
For more information on oaks, we highly recommend, “The Nature of Oaks” by Douglas Tallamy.
Emina Darakjy is a past president of Pasadena Beautiful and its present Tree Program Chair. Darakjy says she has always had a passion for trees and that she is involved with several other tree organizations such as California Re-Leaf, the Arbor Day Foundation and American Forests. She is a past president of Street Tree Seminar Inc. and the present president of the California Urban Forests Council.
One thought on “Pruning an Oak Tree, When, and If, You Should Do It”
The Nature of Oaks by Doug Tallamay is a great recommendation. However, some of the information about pruning oaks provided here is inaccurate. For instance, “pruning to open up the canopy a bit” exposes the interior branches to sun damage and may stimulate the tree to produce succulent new growth that is subject to mildew. Which, is exactly what happened to the mature Coast live oaks that used to be lining the parkways on Tujunga in Studio City post pruning. Several of the Tunjunga oaks got disease after a City pruning project where the oaks were thinned and lower limbs were up-skirted. Only dead, weakened, diseased, or dangerous branches should be removed. Necessary pruning should be done August and September for our evergreen species like the Coast live oaks and during the winter dormant period for our deciduous oak species like the Valley oak. In general, you should never prune a tree during its growth period. Coast live oaks growth period is fall to spring. Given that more than 300 species, including birds, butterflies and bees, depend on oaks for food and shelter and we are in a biodiversity extinction and climate crisis, we need to get their care right. Please go to Californiaoaks.org, for expert information about oak tree care. Note, the Oak Foundation recommends pruning Coast live oaks in July and August but I recommend late August to early October to avoid prime bird nesting season in SoCal.