There are many plants that are quite showy as they creep over the surface of the ground and are even showier if elevated. Large pots and window boxes give plants height and more vertical display as the plants spill over and hang downward. Small pots do the same if elevated on a pedestal or even better, suspended from above as hanging pots. Hanging baskets have additional plants growing through the mesh and moss (or soft tree bark) on the undersides of the baskets.

Hanging pots and baskets can be hung from eave rafters, arbors and even tree branches. A hook over a small branch or a wire around a larger branch will need to be adjusted to avoid girdling as the branches grow. A hook screwed into a limb should be backed out as the limb grows to avoid getting overwhelmed.

Window boxes were likely invented in Venice, Italy, to contain ivy geranium and nasturtium, which were used as mosquito repellent. This was, of course, before window screens or air-conditioning were invented. The lack of garden space was probably another motivating factor. Window boxes are now useful, even where space is not such a commodity, to display colorful flowers as close as possible to the home interior, and to grow herbs as close as possible to the kitchen.

Not many modern homes are equipped with window boxes, and many that were have since had them removed. The main problem is that window boxes can cause rot in the walls that they are attached to, something to consider when installing new ones. It helps to keep the gap between the boxes and the walls clear. Racks that hold pots are less risky because of the space between the pots and the walls.

A window in my home presented a challenge. I wanted some greenery between the window and the unremarkable view of the garage roof and driveway below. However, I did not want to install a window box. Nor did I want to hang pots from the eave near the top of the window, where they would block sunlight. I instead hung potted white impatiens on chains so that they are at the level that a window box would be. Without shading the window, they obscure the view below but not the view of Mt. Hamilton.

Trailing plants--those that hang downward--are best for hanging pots and baskets. Lobelia, sweet alyssum, petunia, portulaca, nasturtium and verbena are some of the trailing warm-season annuals that can be planted soon. Ivy geranium, spider plant, orchid cactus and burrow tail (sedum) are good perennials. Ground covers like campanula, gazania, dwarf periwinkle and English ivy are also good choices.

Prostrate plants--those that grow horizontally and flat or with a weeping habit--are also useful for larger pots on the ground, and window boxes. Annual impatiens, perennial lotus and woody fuchsia are ideal. A Japanese maple-grower from Saratoga actually grows rooted cuttings (without trunks) of weeping Japanese maples that cascade out of pots.

Just a reminder: The San Francisco Flower and Garden Show is beginning at the Cow Palace. More information can be found online at www.gardenshow.com or by telephoning 800.569.2832.

Flower of the week: Shamrock

There are actually a few different species of annual or perennial shamrock that become available around St. Patrick's Day. Perennial white clover, Trifolium repens, is probably the most popular. The shamrock that I found at Trader Joe's is everblooming shamrock, Oxalis regnellii. Wood sorrel and annual hop clover are also popular.

Shamrocks are usually found as small potted plants in florists' shops or supermarkets, like poinsettia at Christmas or lilies at Easter. All have trifoliate leaves, divided into three cloven leaflets. Their small white to pink flowers bloom just above the light green to dark maroon leaves. Although they can be planted in the garden, they can become invasive.

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