It’s Time To Bring The Gladiolus Back

As you may have noticed, gardening trends and the fancy of gardeners go in cycles. Plants and techniques go in and out of favor just like fashions, cars and artwork.

There are booms and busts, but in the end everything seems to come back and become new. Such is the case with Gladiolus.

I can remember when Gladiolus were in just about everyone’s garden, though often relegated to the very back or staked in a back cutting garden. But they’ve disappeared. I think they came to be looked upon as too common, even possibly as too easy, in a day when designer perennials can go for $100 a pop and tender tropicals have become the rage while troughs, pots and planters have become the designer’s edge. But it’s time to bring the Gladiolus (aka the sword lily) back, and I’m here to help.

Call them Gladiolus, gladiolas, gladioluses or, simply, glads. These are plants that are easy to grow, well suited for our local soils and downright inexpensive if you aren’t too picky about the colors and types as they can be purchased for as little as 30 cents per corm or up to several dollars a corm if you want the latest and rarest introductions. Mostly non- or lightly scented, the only one in the family that has a remarkable scent is the Acidanthera or Abyssinian Gladiolus.

Glads are grown primarily for their flowers and are one of the more spectacular cuts you can grow, lasting at least a week in the vase. They also are great performers in the back of the garden as they are relatively tall, and some are worthy of being specimen plants or planted en masse. They require full sun and will disappoint you if they are grown in the shade. Our sandy soils suit them just fine as they prefer good drainage and resent wet soils. They should be planted in a different spot each year to prevent problems of viruses and insects that tend to remain in the soil so they ought to be rotated around the property or garden just as you would (or should) rotate your vegetable crops in that garden for the same reason.

The corms (they are not really bulbs), which are tender, are planted later in the spring when the trees begin to leaf out. Plantings can and should continue on a weekly basis through mid June to provide a long season of blooms and extended maturity. Planting depth is about 6 inches for the largest corms; if planted deeper, flowering will be delayed. If grown in rows, the spacing between the plants will be dictated by the purpose of your planting. Those who end up growing glads for exhibition and shows will plant the rows about 28 inches apart with corms planted on 8-inch centers. If, however, you are simply growing them for cutting and use around the house or to give to friends, your spacing can be much closer with a reduction of almost half the mentioned distances.

Any loose skins that are on the corms should be discarded before planting as this will enable straight stems to form instead of crooked ones that might be crippled by emerging through the tough husk. Place any that have already sprouted so the sprout will grow straight up. If two sprouts are growing at different angles you can cut the corm in two between them, making sure you get a piece of the basal scar on each.

If you are going to try to grow exhibition-size glads, you need to de-eye the corms. This means rubbing or cutting off the side sprouts on the corm and leaving just the big one at the top center. In this way you are concentrating the bulb’s entire energy on the main spike instead of letting it be divided between two or three spikes. Leave on the largest of the center eyes. Cut out the others using a clean knife that you can dip in a bleach solution (1 part bleach to 14 parts water). Let the cut surfaces harden for a few days before the corms are planted.

As you’re ready to plant the corms, have some markers on hand to tag the various varieties. Out of sheer curiosity you may want to know what you’ve planted once they begin to bloom. If you plan on recycling your corms for a second year then knowing which variety is which can be critical unless you’re willing to put up with a general mix.

Fertilizer is generally added to the soil prior to planting, and it’s best to band the fertilizer to the sides of the planting rows so it doesn’t burn the emerging roots. Organic fertilizers are the longest lasting and can be supplemented with additions of liquid organics applied during the growing season. Be careful to limit the amount of nitrogen you use, though, as overdoing this element will result in plenty of heavy foliage that will weigh down the plant but provide few flowers. A fertilizer with the ratio of about 1-2-1 (5-10-5, etc.) seems to be best.

Glads need about an inch of water a week so if it doesn’t rain add what’s needed to make up the difference. Soaker hoses or drip lines are perfect as they keep the water off the foliage and emerging flowers, but you can also run the water down a shallow trench along the line. In the heat of the summer the plants will enjoy some overhead watering that will cool them down, but make sure it’s done in a manner that allows the plants to have dry foliage and flowers before the sun begins to wane in the late afternoon.

Aphids and thrips are the insects to watch out for, and both can be controlled with vigilance, organic sprays, sprays of water, and beneficial insects. The roots of the plants can be easily damaged so cultivate gently and use mulches to keep the weeds down.

When you cut bloom spikes (early in the morning) leave at least four leaves on the plant so the corms will mature properly for next year. Use a sharp knife (never a scissors or pruner) and cut the foliage downward at a slant. The bulbs mature about six weeks after blooming and if you’ve cut the flowers off correctly no seed will set. The bulbs can be lifted as soon as all signs of growth have stopped, and there doesn’t seem to be any benefit in waiting for frost or for the foliage to turn brown. You can use paper bags (not plastic) to separate your varieties and label the bags or bag them en masse if you don’t care how the planting comes out next year. Remove the foliage as you do your bagging, cutting the foliage a half inch above the corm.

The corms can be cleaned by hosing them off or by dunking them in a bucket of clean water, and some may want to add a fungicide into the dipping process as a bit of insurance. Allow the corms to dry in a bright warm spot for about three weeks, by which point you will be able to twist off the old corm, retaining the new one. The corms can be stored in wooden boxes with screen bottoms or a plastic box that has a screen top you’ll add. The corms should be stored right side up so the sprouts that form will grow straight up. Storage should be at about 40 degrees so an unheated garage or an unheated basement or root cellar is perfect.

Lots of companies and catalogs offer the most common glad corms, and if you find some referred to as a “utility mix” or “field run,” these are the unsorted picks from the grower’s field that are not graded or sorted. Mixes like this can be very inexpensive and may from time to time yield some surprises.

For more interesting varieties check out the website of the North American Gladiolus Council at gladworld.org. In the middle of the home page click on “suppliers,” and you’ll find a whole world of incredible offerings. You can also get more cultural information on this site as well as hook up with other glad growers who will be happy to help you out.

Old House Gardens (oldhousegardens.com) is also a great source for information and heirloom glads. And don’t forget your local garden center. Virtually all of them will have prepackaged glad corms and some of the larger local retailers may have as many as a dozen or more individual varieties that would make great starters even if you only want to do a couple of dozen for your first try.

So, opportunity is knocking again, and even if you don’t save and replant your corms this is still a fun and inexpensive plant to work with. Get glads, and keep growing.