Winter weather will likely continue sometime between now and spring, but the recent weather that is more typical of spring has confused many species. Many spring bulbs, such as daffodil and narcissus, have begun to bloom somewhat prematurely. Some saucer magnolias and star magnolias have also initiated bloom. Most seem to suspect that it is still winter and are therefore blooming sporadically, but others are in full bloom.

This weather is pleasant while it lasts but may eventually cause some problems in the garden. Winter pruning of many deciduous species must be completed during dormancy. If, however, dormancy is prematurely disrupted and vascular activity resumes, the necessary pruning cannot be completed without damaging the tree or plant while it is most sensitive. Fruit trees and roses, for example, must therefore be carefully monitored if immediate pruning is not possible. If vascular activity such as swelling buds is observed, pruning cannot be delayed.

Timely pruning unfortunately cannot protect prematurely active fruit trees from the resumption of winter weather. Immediate resumption of cool weather might delay premature bloom enough so that it actually occurs during later winter or early spring, after the damaging winter weather. More of the same weather will otherwise cause early bloom that will very likely be damaged by later frost, wind or rain. Even if bloom is completed while the weather is unseasonably warm and dry, the developing juvenile fruit of most species is easily damaged when winter weather returns.

Irrigation may also become a concern during this pleasant weather. During normal winter weather, irrigation should be very minimal, if necessary at all. Only garden space or containers under eaves, lanais or other structures should require regular irrigation. Such irrigation should also be minimal because evaporation of soil moisture, evapotranspiration (evaporation of moisture from foliar surfaces) and vascular activity are inhibited by cool weather. Without rain, supplemental irrigation may furthermore become necessary to sustain unseasonable vascular activity in areas of the garden that are not so sheltered.


Tree of the Week: Madrone

During a recent trip to Pioneer in the foothills of the Sierra Nevada mountains, I unexpectedly observed some familiar madrones, Arbutus menziesii, among several unfamiliar species. I have seen madrone throughout the coast ranges from the Olympic Peninsula to Santa Barbara but I have been informed since returning from Pioneer that the natural range extends from British Columbia to Southern California and includes sporadic populations in the Sierra Nevada foothills.

Madrone may form a large shrub but is usually an irregularly structured tree between 15 and 50 feet tall. Old specimens may be twice as tall, particularly in the Pacific Northwest. The rounded canopies are typically broad but may be sparse in madrone groves or if competing with other trees. Smooth tan or red bark is more or less exposed by older bark that flakes away like fine flakes of old paint. The 3- or 4-inch-long oval leaves are shiny and deep green with grayish green undersides. Trusses of small, white, urn-shaped flowers appear in spring and are replaced in autumn by sparse orange or red berries that attract birds through winter.

Minimal irrigation should only be necessary while new specimens disperse roots. If irrigation is applied after that, it should be rare. Soil should drain well. Madrone is useful in areas that are not landscaped but may be too messy for refined gardens. It is not commonly available but may be obtained from nurseries that specialize in California native species, such as Yerba Buena Nursery in Woodside.

Horticulturist Tony Tomeo can be contacted at 408-358-2574 or at LGHORTICULTURE@aol.com.