Fall and Winter Tree Care

Serving Marin County for over 35 Years

34 De Luca Place, Suite M

San Rafael, CA 94901


Phone: 415-472-7105

Fax:†††† 415-721-2470


What problems are you seeing right now?

Right now we are seeing a phenomenon that is new to Marin County which is the insect infestation of Myroporum hedges by Thrip.††† This causes leaf curling and deformity.† This insect is difficult to control so Iíve been recommending an immediate application of a foliar pesticide and a soil drench systemic pesticide because it is controllable in the early stages.† We are also seeing an ongoing problem with inland Monterrey pines.† They require much more irrigation because they are a coastal fog bank tree that requires a cooler, damp climate.† These trees become stressed when planted in an arid location.† Healthy trees produce toxins in sap that discourage insect infestation; unhealthy trees lend themselves to secondary problems such as Red Turpentine and Ips Engraver beetles.††

What insects are active in the Fall and which trees are affected?

Oak trees have a number of insects that are leaf chewers as well as Ambrosia Bark beetles that bore into the tree and carry water mold disease such as Sudden Oak Death (phytophthora).† Homeowners should continue the annual SOD treatment with Agrifos, as well as pesticides to control the beetles.† Ambrosia Bark beetles, as well as the previously mentioned Red Turpentine and Ips Engraver beetle, are in flight from March through November.† Birch trees are vulnerable to Bronze Birch Borer infestation in this same time period.

What are important considerations for homeowners as we move towards winter?

We never know what kind of winter we are going to have.† Pre-winter safety pruning is one of the most important actions that a homeowner can take.† Pruning relieves weight, reduces wind resistance, controls limb failure and keeps trees from uprooting.† Trees should not be over pruned because that disrupts their equilibrium.† Certified arborists can recommend the right pruning techniques.† It is important to keep trees away from the home all year long, especially the roof - limbs that are close and/or making contact can bridge roof rats and carpenter ants.† Of course, safety pruning for fire prevention is very important in the summer and fall months.

Are there any trees that should be sprayed in the winter months?

Deciduous trees such as fruit trees as well as other trees with a history of chronic infestation should have dormant spraying to control insect and disease.

Are there any trees that should only be pruned in winter months?

Because of our Mediterranean climate in Marin, most trees can be pruned in any month of the year in moderation.† However, Monterrey Pines and European and American Elms should only be pruned in the winter.† When these trees are pruned during the months that the different beetles are in flight, the fragrance of the sap from the pruning cuts may attract these vectors back to the tree.

What is the biggest mistake that most homeowners make?

80% of a treeís roots are within the first two feet of soil regardless of age and size. The primary problem that we see is either not enough water or too much water with poor drainage.† A stable environment (non-compacted soil, proper irrigation, and proper drainage) as well as stable physical structure (proper pruning) will keep trees healthy and resistant to most problems.†

I recommend a one time site consultation with a certified arborist to evaluate the health and safety of your trees and to determine an ongoing tree care plan to protect your property.† Trees die from the top down and you should contact a knowledgeable resource as soon as you suspect a problem.

Robert Morey is the owner/operator of Marin Tree Service which has served Marin since 1976.† He is a Certified Arborist as well as the past president of the California Arborists Association, Northern Counties.