LETTING YOUR PLANTS GO TO POT ISN'T A BAD THING.

Byline: Joshua Siskin

Growing plants in containers has long been acknowledged as gardening's finest art. It therefore comes as no surprise that at the Palace of Versailles - a bastion of French fine arts since the time of the Bourbon kings - a display of flowers in clay pots has been kept up for more than two centuries.

No, the same flowers have not been in these pots for 200 years. Au contraire. These flowering displays are changed frequently, if not as frequently as in the days of Louis XIV.

Vincent LeDonne, who lives in Reseda, recently visited Versailles and learned that, in the late 18th century, ``when the king arose in the morning and was dressed by his attendants, the gardener also had to be present. Whatever color clothes the king wore on that day had to be matched by all the flowers in the garden.'' One of the privileges of being king, it would appear, is that you get to change the flowers as often as you wish.

``In Las Vegas at the Bellagio Hotel,'' LeDonne writes, ``the display is very much the same as at Versailles. I believe they change the flowers by the season. Can you give any hints as to how this is done? How do you keep flowers in bloom all the time?''

Gardeners, as distinct from nongardeners, are especially enraptured by elaborate displays of flowering plants in pots. Anyone who can sustain the opulent, full-flowered look - despite container confinement - earns our immediate respect.

In the Valley, the key to maintaining this look is to select the appropriate planting times and species. For example, for your container to be burgeoning with flowers on Jan. 15, you should have planted it on Oct. 1. Among annual flowers, you could have planted snapdragons, pansies, lobelia, dianthus and alyssum.

Another excellent date for planting in containers is March 1. Plant the same annuals you would have planted in October (except for pansies, which wither in the heat), and add marigolds and petunias to the mix. As a matter of principle, you want to plant when the weather is moderate, just before the growth spikes of early fall and spring arrive.

A final propitious date for planting would be June 1. We typically benefit from a few weeks of so-called June gloom, overcast days that allow plants to settle in before the merciless heat of summer is upon us. In June, plant marigold, petunia, vinca, zinnia and sanvitalia.

Perennials are also best planted on the above dates. At the top of the list of continually flowering perennials would be lavender and ivy geranium. A container plant that has skyrocketed in popularity over the last few years is bacopa, a trailing plant with white or pink flowers. Perennial linaria and perennial nemesia, both in the snapdragon family, are also excellent container subjects that bloom nonstop.

Conventional potting soil, sold by the bag, is an easy way to go when considering planting media for containers. In truth, you could make an equally agreeable mix by combining one part potting soil with one part topsoil, also sold by the bag. The more perennial the plants, the more topsoil you will want in your container soil mix. Potting soil, consisting primarily of aged organic materials, breaks down rapidly while topsoil (consisting mostly of gritty, fast-draining soil particles) endures. Osmocote slow-release or Gro-Power fertilizer should be mixed into the container soil prior to planting. Topical applications of either of the above can also be made periodically.

TIP OF THE WEEK: To see an effective arrangement of container plants, visit the La Reina shopping area in Sherman Oaks, located on the south side of Ventura Boulevard just west of Van Nuys Boulevard. Tall specimens of false aralia (Schefflera elegantissima), tupidanthus (Schefflera pueckleri) and giant bird of paradise (Strelitzia nicolai) were set in large pots only two weeks ago.

For ground cover, a balcon ivy geranium with variegated white and green leaves has been planted around these leafy, arborescent subjects. The only reservation I have about the selected species is their high susceptibility to giant whitefly infestation. It is to be hoped that the openness of the location will allow enough air circulation around the plants to keep those sticky whiteflies, which feel most at home in stagnant air, at bay.