BIRDS CAN GIVE YOUR LAWN WEEDS? READ ON.

Byline: Joshua Siskin

Have you ever seen a crow hopping on your front lawn? You might want to consider putting up a scarecrow. Birds' feet are principle vehicles for the dissemination of weed seeds in lawns.

If there are dandelions in your neighborhood, you will sooner or later see dandelions growing in your lawn. Crows and other birds take great delight in hopping on those puffy white globes of dandelion seeds. The seeds stick to their feet and then are rubbed off when the birds alight on other lawns in the neighborhood.

The dandelion is only one of the culprits in the transformation of a grassy lawn to a field of weeds. In fact, there are several weeds far more troublesome than dandelions could ever be.

Oxalis looks like a mound of clover with dainty yellow flowers. Yet the soft appearance of oxalis belies its tenacity in the lawn or garden. Because of its wiry taproot, it is virtually impossible to uproot oxalis.

There are four grassy weeds that, left to their own devices, will completely take over and smother a lawn within two to three years. Bermuda grass, crabgrass, kikuyu grass and nut grass (actually, nut sedge) have the capacity - individually or collectively - to overwhelm a lawn within the span of a few growing seasons.

A lawn expert with 30 years of experience in weed control recently told me that, based on his experience, most newly sodded lawns turn into weed patches within four years of planting. Weed seeds are brought to lawns by birds, the wind and lawnmowers.

Before hiring a gardener, you should check the lawns of other customers that he mows. If their lawns have weeds, your lawn will surely acquire them, too. Weed seeds stick to lawnmower blades and are carried from one lawn on a gardener's route to the next.

Between late February and early March is the time to apply pre-emergent weed control chemicals to lawns. Pre-emergent chemicals prevent weed seeds from germinating or kill baby weeds immediately after they have sprouted. Some fertilizers include pre-emergent chemicals so that you can make your grass green and keep weeds out with the application of a single product. Bags of granular formulations that both fertilize and prevent weeds can be found at any nursery or home improvement center.

Are you bold? Rip out the front lawn and replace it with a field of so-called freeway daisies (Osteospermum fruticosum), available in white and pale purple. This is the time of year when freeway daisies, once planted extensively along highway embankments in Los Angeles, are in their glory. The bloom is dense, forming a carpet of 2-inch-wide, slightly cupped daisies. Vegetative growth is rapid, with rooted cuttings capable of filling in a circle several feet wide in a single growing season. The only demand freeway daisies have is a well-drained soil. Where soil is heavy, plants will grow slowly and/or die of fungus disease soon after becoming established.

Two vines of note are in full flower at this time. Australian pea (Hardenbergia violacea) has violet-blue pea flowers and Carolina jessamine or jasmine (Gelsemium sempervirens) has yellow trumpet flowers. Both species will readily wind their way up a lattice or railing. Australian pea is more tolerant of dryness than Carolina jessamine. Carolina jessamine also happens to be one of the moist poisonous of garden ornamentals, whose leaves, stems, and flowers are all highly toxic.

In response to the information on hydroponic growing that appeared in this column a few weeks ago, Shelley Smith of Granada Hills has drawn my attention to Foothill Hydroponics, located at 10705 Burbank Blvd., in North Hollywood. Moshen Daha, proprietor of Foothill Hydroponics and sponsor of hydroponics workshops, gives 20 percent discounts to teachers and students. For more information, call [phone].

TIP OF THE WEEK: When using fertilizer that has considerable iron content, exercise extreme caution where there is a bordering sidewalk or other concrete surface. Iron stains concrete orange and, short of sandblasting, you may never be able to remove such marks. If your iron fertilizer should come in contact with concrete, hose it off immediately. Contact for more than a few seconds could result in permanent stains.