Autumn weather in the Santa Clara Valley may be much milder than autumn weather in other parts of the continent identified with autumn foliar color, such as New England and Appalachia, but a few species perform well locally with only minor seasonal weather changes. I have not noticed that the nights have been all that cool, but it seems the flowering pear trees throughout the valley have been noticing something that I have been missing and coloring accordingly.

Flowering pears are perhaps the first to get started with their display and happen to be among the most proficient of trees to display autumn foliar color. Their display is comparable to that of Chinese pistache and American sweetgum (liquidambar), but pear trees are more proportionate to urban gardens and not as messy. American sweetgum, regardless of its innately inferior structural integrity and production of bothersome "maces" (seed capsules), suspends its colorful foliage longer than any other species I can think of. Some continue to suspend their foliage into the end of winter as buds begin to swell with new foliage.

I must, of course, mention my favorite trees: the North American maples. These are the real maples that grow as trees, not those wimpy Japanese maples that most people think of as maples. Almost all maples, including Japanese maples and European maples (but not silver maples), exhibit excellent autumn color, but those that grow into large trees certainly exhibit more than the smaller Japanese maples.

Gingko, tulip tree, white mulberry, poplar and birch all reliably produce autumn foliar color, but their color range is limited to yellow. Chinese tallow can be relied upon for red enhanced by purple. Some shrubbery species, such as witch hazel, as well as some vines, such as Boston ivy, also color well this time of year.


Perennial of the Week: Fountain Grass

The dining room of my first and only apartment in San Luis Obispo had a splendid view of scenic Highway 1. The highway was slightly elevated in that section so that it was at about the same elevation as the windowsills of the backside of our apartment building, which was located only a few feet from the pavement. There were no trees or shrubbery to obscure the view or noise, but the fountain grass (Pennisetum setaceum) that had naturalized on the embankment efficiently concealed from view small road kill and litter. It did not appear to have been installed over the entire area, but seemed to have seeded itself and was perfectly happy without irrigation.

Fountain grass leaves are long and narrow but can collectively form dense clumps that are as high and wide as four feet. Specimens that receive supplemental irrigation may grow quickly and rot in one or two years, but replace themselves with many seedlings that may do the same the following year. Without irrigation, individual clumps are otherwise perennial and should grow more slowly and regenerate after winter dormancy for a few years. Newly installed specimens, of course, require irrigation until they become established, unless planted in winter when rain can sustain dispersion of roots prior to spring. Full sun exposure is preferred.

Fuzzy floral plumes that resemble kitten tails appear during summer and into autumn. Floral color ranges from purplish to pinkish bronze. If fountain grass begins to become invasive, flowers should be removed before they dry and disperse seed. This procedure unfortunately prevents natural replacement of older grass. Removal of flowers from within a few feet of the perimeter of a mass planting should inhibit invasiveness, but allow some seed to replenish the colony. The cultivar "Rubrum" does not produce much viable seed and is therefore not invasive, but is also unable to replace itself. "Rubrum" produces bronzy red foliage and pinkish flowers that fade to taupe.

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