Local vendors will be marketing new and unusual plants as well as garden art, pots and gardening paraphernalia. Some of my colleagues and I will, of course, be available for free consultation. Guests can also visit with representatives of various flower growers, nurseries and garden clubs. Short lectures will feature topics such as gardening for wildlife, organic fertilizers and integrated pest management. There will be activities for children.

Spring in Guadalupe Gardens will be from 9 a.m. to 3 p.m. at Columbus Park, at Spring and Taylor streets in San Jose. Admission and parking are free. More information may be obtained online at www.grpg.org/sgg or by telephoning 408.298.7657.

The 33rd annual Wildflower Show will also be April 23 and continue April 24. Free classes will discuss topics such as identification of native species, gardening with native species and gardening for butterflies. Seed of various native species, books, posters and note cards will be for sale. The annual wildflower show will be at the Hospitality Management Building of Mission College, located on the left of Great America Parkway, directly north of Highway 101 in Santa Clara. Admission and parking are free. More information may be obtained online at www.cnps-scv.org or by telephoning 650.691.9749.

The open house at Bay Laurel Nursery, which began on April 9, will continue on April 16, 23 and 30 and conclude May 7. Different rhododendrons will be blooming each week. With the exception of April 23, when I will be at Spring in Guadalupe Gardens, I will be at the open house and available for horticultural consultation. Bay Laurel Nursery is located at 1554 Bean Creek Road in Scotts Valley. The open house runs from 10 a.m. to 4 p.m. More information may be obtained online at www.baylaurelgardens.com or by telephoning 831.438.8770.

Flower of the Week: Wisteria

As if the rhododendrons and azaleas of the open house at Bay Laurel Nursery were not sufficiently spectacular, a few other blooming ornamentals, including wisteria, have been brought in to add variety. The somewhat rare Japanese wisteria, Wisteria floribunda, has larger floral trusses and leaves. Each foot-long or longer leaf is divided into more than 15 leaflets. Fragrant floral trusses that appear about now as foliage emerges are typically about a 1 1/2 feet long. Florets at the base of each truss begin blooming first and are sequentially followed by more distal (farther from the base) florets. Trusses are very pendulous and hang upside-down, so basal flowers are at the "top" of each truss. Bloom may be pale purple, pale blue, pink or white.

The much more popular Chinese wisteria, Wisteria sinensis, is more finely textured than Japanese wisteria. Leaves are smaller and are divided into less than a dozen leaflets. The smaller but more profuse floral trusses also bloom about now, but most of the florets bloom simultaneously and foliation is slightly delayed until bloom begins to fade. The pale bluish purple or white flowers are only mildly fragrant. Chinese wisteria is more tolerant of light shade than Japanese wisteria.

Wisteria is certainly not a "low maintenance" vine. It needs specialized pruning during winter dormancy to enhance bloom and confine the otherwise invasive vines. Additional light pruning often becomes necessary during summer. Wisteria vines are so voracious and become so heavy that they can overwhelm trees and crush inadequate trellises, lattice and the neighbor's old Dodge that has been parked in the driveway too long. Occasional application of fertilizer enhances vegetative growth of young vines, but will inhibit bloom of more mature vines.

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