Tips for All Seasons

Watering

Overwatering can be as harmful to trees and shrubs as underwatering. With the primary exception of lawns, most established non-native plants do not need water more than once a week (and would probably not get more in their original habitats).

In drought years, our local native trees and shrubs, which can normally get by, do well with occasional watering - such as 2-3 deep soakings - spaced throughout the late spring and summer. Monterey Pines benefit greatly from deep watering during any dry season (see the Fall/Winter 1991 issue of Tree Tips for guidelines).

When watering trees, focus on the wide area within and outside the dripline (canopy's edge), where the feeder roots are most abundant. Avoid the sensitive area around the base of the tree (where many people water - it's susceptible to root rot.

Mulching

Mulching Trees and shrubs - an idea gardeners borrowed from the leaf litter that covers the ground in most natural habitats - protects soil from overexposure to wind, rain, and sun. This improves soil quality, prevents erosion, and reduces the frequency and amount of watering and weeding needed. Be generous and spread it 3-4" deep (except very near the trunk, where it should be very thin) and you'll get better results.

Aerating

Plants need well -aerated soil to stay healthy. Their roots thrive in soil wit an oxygen count of 18-22% and the compacted clay soil found in most East Bay yards often has much less. Proper aerating does for your trees what an aerobic routine does for your body. Aerating oaks, Monterey Pines, and any unhealthy tree in compacted soil is at least as important as proper watering and pruning. The basic aerating process involves using a deep-root irrigator to create holes1-2' apart and 1 1/2-4' deep and filling them with porous organic matter. You can buy an inexpensive irrigator in nurseries, but more compacted soil may require more specialized equipment.

Pruning

Regular pruning (once a year for some plants, less often for others) keep the trees and shrubs much healthier than does drastic or crisis pruning.

Procrastinating about pruning can actually make things more expensive (and certainly less attractive) later on. For example, if you have a tree or shrub growing between houses and you neglect to thin its upper parts regularly, you may discover that it has died back underneath and you have irretrievably lost your screening. Or you may find that the oak or magnolia that has been slowly growing into your view can no longer be reduced without compromising its health and you may be forced with either losing the view or ruining the tree.

Nevertheless, it's better to leave you trees and shrubs underpruned than to subject them to poor pruning, which can cause irreparable damage. If you want to do your own pruning, take some classes -Merritt College's Horticulture program has great ones. This can also help you evaluate the work of any professional you hire. It's always a good idea to look at a professional's portfolio and to ask for referrals to nearby clients whose trees you can view.

Certain practices, particularly topping single-trunk trees and stripping out the interior canopy of trees, have been discontinued by professional arborists because we know that they undermine the tree's health and safety. For example, cutting just a few feet into the top of a redwood can result in a hazardous tree 10-15 years later. Remember that trees and shrubs are complicated life forms and that caring for them is both an art and a science.

Disease and Pests

If you give each tree and shrub an optimal environment in terms of light and soil conditions, you will find that you have fewer problems with disease and pests. In fact, a strong, healthy plant can tolerate a few bugs.

If you do spray, don't spray your entire yard. Doing so will kill beneficial insects, endanger birds, and may actually increase your pest problem. Try to use least-toxic alternatives, such as Safer Soap (for aphids, thrips, etc.)B.t.(for oak moths), and lime sulphur dormant spray (for many fruit tree diseases). An excellent guide to your options is Common Sense Pest Control - call BIRC at 524-2567 to order a copy.

Over the years, our three Certified Arborists have, among them, given consultations to thousands of East Bay homeowners. In the process they have both gathered and shared considerable wisdom regarding tree and shrub care in the East Bay. If they were asked to distill all this into one bit of advice, it might be this: learn how to grow plants in harmony with nature. Not only will you have healthier plants, but you will also increase your feeling of connection to and love for the place where you live.