Gladioluses: lots of color at a low cost

Gladiolus corms (bulbs) cost as little as 10 cents apiece, so you really can't afford not to try them in your garden. Color shadings run the gamut: white, red, pink, yellow, orange, salmon, blue, lavender, purple, and green, plus white with red blotch, yellow with red blotch, and other combinations. Within this range, additional differences are found in plant shape and leaf color, shape, and size.

If you like to think small, miniatures are 36 inches high with florets (flowers) about 21/2 inches wide. Standard sizes range from 38 to 48 inches high and the flowers can be as wide as 8 inches.

Gladiolus corms, sold singly and in packs, are readily available at garden centers and variety stores, and they can usually be planted as soon as they appear and then at regular intervals for several months to provide staggered bloom for cutting purposes.

What do you look for when buying ''glads'' for your garden?

When inspecting the corms, look at them in the same way you look at produce in a supermarket. A rotten corm obviously won't grow.

A corm that has sprouted is not necessarily bad, but you will want to break the sprout off if it's more than an inch long. You won't be discouraging growth. There are other ''eyes'' on the corm and the glad will grow a new sprout after planting, especially if you encourage it with lots of water immediately after placing it in the ground.

The average corm is three-quarters of an inch or larger in size. To plant, place it with the concave, or hollow, side down and approximately 4 or 5 inches deep. The distance between the corms should be about 5 inches.

While nutritious, sandy soil is ideal, gladioluses are really quite adaptable despite their elegant appearance and do well in heavier soil as long as they have good drainage. A preplanting fertilizer is strictly optional, but make sure the corm is protected by a layer of unfertilized soil.

Soaking the ground thoroughly is a must. Then give a hearty watering every couple of weeks, the rule of thumb being to allow the soil to almost dry out between times.

The only steadfast requirement for glads is sun since their ancestors are from South Africa and the Mediterranean area. They will, however, tolerate a bit of shade, particularly if grown in arid areas.

You can stake your glads, if you wish, but it's also possible to wait until the plant gets ready to spike and then build up the soil some 2 or 3 inches around the base. Tamp down the soil with the back of a hoe or your foot. You will then have a natural ''prop'' to keep the plant upright during bloom.

Should you want gladioluses for indoor decoration, cut in the bud when the first floret starts to open. Leave at least a foot of stem and leaves remaining in the ground. How you cut, diagonal or straight, doesn't make much difference, but your flower stem should go directly into a mixture of water and nondietetic Squirt or Seven-Up soda.

What you're after is the combination of citric acid and sugar. Glads love sugar and their flowers respond to the lower pH which the acid creates. The ratio is one part soda to four parts water. Place the flowers in a very clean vase with the fluid.

As the flowers age, take them off. One water change, after a 5-day period, is ample. At the same time, cut the stem about 5 inches. If you don't have any citric soda left, add more water to the container rather than change it.

Any foliage remaining in the garden should be left there from 3 to 5 weeks to allow corm maturation. However, you don't have to let the foliage die down completely. Just take your hoe and chop it off at the base. If you live in a warm-climate area, such as southern California, the glads will come up again the next year. If you have soggy or very cold winters, the price of bulbs is so inexpensive, in most cases, that it might just pay you to purchase new bulbs rather than dig up the old corms, dust them, and put them in storage.

Rumors abound that gladioluses turn white if left in the ground, but there's only a slight chance of that actually happening. The basic explanation for the rumor is that the whites are hardier so they come back double the next year, while the others, less hardy, will come back half the number. It's a simple case of mathematics.

Glad buffs can also multiply their collection from bulblets that are attached to the parent plant. You can grow glads from seed as well, although it's not commonly done. Just allow the flowers to remain on the plant. If the bees pollinate the flowers, you'll get seed. Each seed in a seed pod will produce a different variety.

Plant the seeds less than an inch deep, keeping the area wet, and in six months you will have some corms. The first year you usually won't get any flowers, but the second year will take the guessing out of what color/size/shape you have created.

If you want more information on gladioluses, write to Samuel N. Fisher, All-America Gladiolus Selections, 11345 Moreno Avenue, Lakeside, Calif. 92040. AGS is an affiliate of the North America Gladiolus Council which rates seedlings , runs a gladiolus hall of fame, does research, and even sponsors competitions.