Volunteering for the Compost and Drought Tolerant Garden Workdays on the first Thursday of every month is a good way to learn about the various methods of composting and worm bins. Instruction by master composter Phil Cornish will help guests determine which method is best for their own gardens.

Wednesdays are workdays in the Courtyard Garden, the Drought Tolerant Garden and the Heritage Rose Garden, which also has workdays on Saturdays. Volunteers are also needed to get ready for and to help during the Water Wizard Festival on May 27.

Workdays will be between 9 a.m. and noon at the respective gardens. Guests can meet at the Garden Center, located at 715 Spring St. (at Taylor Street) in San Jose. More information may be obtained online at www.grpg.org or by telephoning Lucy Perez, the volunteer coordinator, at 408.298.7657.

There are still a few other upcoming horticultural events scheduled for this spring. The Open House at Bay Laurel Nursery is not until the five Saturdays between April 9 and May 7, but more information can be obtained online at www.baylaurel gardens.com or by telephoning 831.438. 8770. Spring in Guadalupe Gardens is likewise not until April 23, but more information can be obtained online at www. grpg.org/SGG. Los Altos Nursery has, incidentally, been open for about a month, but no one told me to write about it until now.

Tree of the Week: Silver mountain gum

Contrary to what most other horticulturists or arborists would say, many species of eucalyptus are very useful in compact urban gardens. Silver mountain gum, Eucalyptus pulverulenta, is unfortunately not one of them, but it is a striking feature in mid-sized or larger gardens that can accommodate it. Mature specimens are less than 30 feet tall, and most are less than 20 feet, but they behave like larger trees. The trunk and main limbs become disproportionately hefty, and foliar litter mixed with twigs and small seed capsules can be messy. Silver mountain gum may therefore not be appropriate near decks, patios or lawns, but it is a good choice for areas with ground cover, where litter is not a problem. Fortunately for those that happen to be planted near pavement, their roots are remarkably complaisant.

Silvery foliage is the most striking feature of the silver mountain gum. Occasional hard pruning promotes more abundant production of the round sessile (without petioles) juvenile foliage that is popular for floral arrangement. Adult growth is lanceolate and not quite as silvery as the juvenile foliage. The small clusters of white flowers that bloom during warm weather are not remarkable but can be profuse among a third type of foliage that is rounder than standard adult foliage. The tan bark is finely furrowed with long striations. Branch structure is irregular and can be rather awkward.

Eucalypti do not like to be confined in containers and will need considerable time to recover in the garden if roots have previously become pot-bound. It is therefore very important to acquire the most vigorous young trees, even if they seem to be disproportionately small for their cans. No. 1 (1 gallon) size trees are generally not available but would be the best size to plant. They should quickly become established and grow like ... well, like eucalyptus. No. 5 is a good compromise. No. 15 trees provide more immediate gratification but may need several years to recover from root confinement. Boxed eucalypti are fortunately rare. I only see them after they have already been installed in a landscape, when I inspect the site to determine why the trees are dying.

Horticulturist Tony Tomeo can be contacted at 408.358.2574 or at LGHORTICULTURE@aol.com.