The climate in the Santa Clara Valley must be the best in the world. Summers are relatively mild with minimal humidity. Autumns are cool enough to stimulate foliar color among several species. After that, winter does not become too uncomfortably cold. Only a few species require protection from frost and only for a few days during winter. In fact, during our normal Christmas season, there have only been a few nights of mild frost.

In other climates, many species that are easily grown here, including citrus and most species of palms, either can not be grown, or must be brought inside for winter. My father who now lives on the Olympic Peninsula must even bring much of his coniferous bonsai stock into a greenhouse to prevent the soil in the dishes (pots) from freezing. Unlike the inexpensive greenhouses that are popular here, a much more substantial greenhouse that will support the weight of snow is necessary. Fortunately, he can afford it because he did not send me the new Buick I wanted  for Christmas.

Frost protection is much simpler here and only necessary for a few species. Many sensitive species may be successfully grown without protection if strategically located in protected areas of the garden, such as under eaves or larger trees, if sun exposure is adequate. Under the eaves of heated homes, radiant heat from an exterior wall will also be appreciated. Exposed walls that face south are warmer during the day and consequently radiate more warmth at night. Incidentally, such walls are good locations for species that require protection but enjoy warmth in summer, such as bougainvillea and hibiscus.

The most sensitive species that may be damaged by even mild frost should be grown in containers if practical. They may then be relocated during frosts or for the entire season. Larger items are obviously more easily relocated for the entire season than every time they are threatened by frost. Porches, lanais, carports and covered patios are actually better protection than larger shade trees. Those of us with nothing to park in a garage may use the space to store plant specimens if sun exposure through windows is adequate.

If ‘tenting’ specimens that are installed in exposed areas, the covering material should not touch foliar surfaces. Otherwise, moisture that condenses on the cover may freeze on the foliage and damage it worse that it would have been if left exposed. Tent covering should be removed during the day for adequate sun exposure and air circulation.

One of my neighbors in San Luis Obispo placed either (tire) inner tubes or bleach bottles painted black, filled with water around sensitive specimens so they would be under the tents at night. The black rubber or paint would collect and transfer solar warmth to the water from which the warmth would radiate at night. It was unsightly and I never quite figured out how the water got inside of the inner tubes, but I don’t remember seeing any frost damage in that garden. However, I would think that the water would be frozen by morning before dawn when warmth is most critically needed.

Frost sensitive species should not be pruned too late in summer or autumn because the resulting new growth is most sensitive. If a specimen becomes damaged by frost, it should not be immediately pruned. Proper tree care is a must. Damaged parts may be unsightly, but insulates inner growth that may not have been damaged. Pruning not only exposes inner growth, but stimulates new growth that will very likely be damaged.

Winter garden and tree maintenance must be thought out carefully to preserve the beauty of your landscape design.