Arborist Blair Glenn of Saratoga Tree Service will be available between 1 and 2 p.m. for advice concerning arboricultural concerns. Horticulturist and San Jose Mercury News garden columnist Bob Chapman will also be present at that time to address issues of plant diseases. Horticulturist Tom Ligget will staff the booth from 9 to 10 a.m. and again from noon to 1 p.m. for questions concerning general gardening and irrigation.

Ligget established the Heritage Rose Garden, which is now one of the most extensive collections of old world roses in the world, right here in Santa Clara County! The Heritage Rose Garden (which should not be confused with the San Jose Municipal Rose Garden) is located within Guadalupe River Park and Gardens, across Taylor Street from Spring Street. It will host docent-led tours during the event. Additional docent-led tours will continue May 5, 12 and 19 at 10 a.m. and 6 p.m. Reservations are not necessary; admission for the tours during May is $3 per person at the beginning of each tour. Free parking is located on Taylor Street. More information about the Heritage Rose Garden tours or Spring in Guadalupe Gardens may be obtained by telephoning 408.298.7657 or 408.277.8845 or visiting www.grpg.org.

The Santa Clara County Rose Society will be conducting the 61st annual Rose Show, also this weekend on the lower floor of Vallco Fashion Park, 10123 N. Wolfe Road in Cupertino. Those attending one of the many other horticultural events on Saturday may not be able to visit the Rose Show between 1 and 5 p.m. on April 26 but should not miss it April 27 from 11 a.m. and 4 p.m. Young garden enthusiasts and beginning exhibitors are welcome to submit specimens and arrangements for competition. Exhibitors may arrive at 6 a.m. Additional information is available by telephoning publicity coordinator Karl Dost at 408.264.4278.


Tree of the Week: Dawn Redwood

While at Cal Poly, I noticed that about half of the trees within a prominent group of redwoods seemed to be somewhat discolored and not structured like the others. Later in autumn, the foliage became brown and eventually defoliated. I wondered why the trees would have defoliated so rapidly and why such obviously deceased specimens were not removed. As they foliated in spring, I learned that they are actually healthy dawn redwoods, Metasequoia glyptostroboides, and why they should not be mixed with coast redwoods! They may resemble the coast redwood during summer but never look "quite right" when compared.

Emerging foliage is soft and bright lime green. It darkens with age but is typically lighter green than that of the coast redwood. It is obviously very different when it becomes reddish brown in autumn and abscises during winter. Cones are more profuse, but smaller than those of the coast redwood and remain suspended when foliage is gone. Bark is reddish brown, like cinnamon. Branches curve upward and divide into smaller branches more freely than the horizontal limbs of the coast redwood.

Rich and well-drained soil is preferred, but dense soil and regular irrigation is easily tolerated if irrigation is not excessive. Reflective glare can cause foliar burn during warm and dry weather. Although dawn redwood may be damaged by extreme cold, it is not as sensitive to cold weather and snow as coast redwood. Dawn redwood is interesting as a single specimen and also in groves as a graceful coast redwood substitute that does not obscure sunlight during winter. Incidentally, dawn redwood, gingko, bald cypress and a species of larch are all somewhat rare but are the four more common of the deciduous conifers.

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