The Cupertino Courier

Gardening

California sycamores grow near waterways and often develop multiple trunks and gnarled branches. If used in landscaping, these tall trees prefer lots of room, regular irrigation and full sun exposure.

Giving advice on everything from wastonias to snail bait

By Tony Tomeo

Regardless of my disdain for computers, I have found email to be quite useful. The many questions or comments I receive often remind me of topics I neglect to discuss, since I do not encounter them in my own simple garden. I thought I should mention a few.

Dawn Isis of Campbell asked about 10-year-old watsonias that are producing abundant foliage, but not many flowers. This is actually common among established watsonias as they proliferate and get crowded. A few other perennials do the same thing. Healthier groups, or "colonies," ironically get crowded sooner because they multiply more each season than stressed colonies do.

This problem becomes apparent now, but cannot be corrected until the bulbs are dormant in winter. At that time, they can be dug, divided and replanted. Many people simply divide them into smaller clumps of several bulbs clinging together, but I prefer to separate and pluck the individual bulbs (remove old foliage and debris) before planting them with a bit of space between them. Bulbs that were severely crowded may need a year after division to recover, but should do just fine the following year. If divided regularly every few years when diminished bloom is first noticed, bulbs should bloom quite happily and continually.

Isis also asked how to prune an already rampant 2-year-old Cape honeysuckle. Actually, I would like to know, too. It is a great plant for large areas where it can grow wild. Yet even with adequate space, it does not know if it is a vine or self-supporting shrub. All it does know is that it will not be confined or forced to climb a trellis like real honeysuckle. By the way, it is natural for overly vigorous plants to produce few flowers.

Roopa Raman of Cupertino inquired about the care of poinsettias in the garden. Unfortunately, in the Santa Clara Valley, poinsettias should not be in the garden. Winters are just too cool. Poinsettias can grow quite tall with scrawny stems, but get frozen back every few years before they can really amount to much. If they get enough sunlight for fuller growth, they sometimes get burned.

Poinsettias, as well as Easter lilies, chrysanthemums and even "florist" azaleas are what we in the nursery industry know as "pot-plants," which simply means they are potted blooming (or foliage) plants for indoors, which are not expected to survive after bloom has finished. They are like cut flowers that have not been cut. Even pot-plants that should be happy locally, like azaleas, initially have serious difficulty adapting to the garden because they were forced into bloom in rather unnatural greenhouse environments.

Patty Bennet of Campbell wanted to warn that although most modern pesticides are relatively safe, snail bait is extremely dangerous to dogs. It is, of course, very toxic, and is also easily ingested. Unlike liquid pesticides that adhere to whatever they are applied to, snail bait is broadcast in the form of small pellets that dogs can find and eat. These pellets are sold in cardboard boxes that dogs can tear into more easily than they could get to pesticides stored in plastic bottles.

Walnut hulls are not nearly as dangerous, but can make dogs rather sick. The garden would be so much safer for dogs if they would simply eat snails instead.

Tree of the Week: California sycamore

Like the native coast live and valley oaks, the native California sycamore, Platanus racemosa, now has a hard time finding a place to live in the Santa Clara Valley. A riparian tree (naturally lives near water), the California sycamore is certainly more tolerant of landscape irrigation than the oaks. The problem is it gets too big too fast. It can grow to about 70 feet tall and 50 feet wide like the oaks, but in less than half the time.

In large landscapes, it develops a picturesque structure, with bulky and often multiple trunks, gnarled limbs and a freeform canopy. The rather smooth bark is interestingly light shades of tan, gray and white. The large lobed leaves are unfortunately susceptible to anthracnose and powdery mildew, which can cause premature defoliation as early as late summer. Tomentum (fuzz) on leaves can be irritating to the skin.

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