Gladiolas

Arriving home today from a weekend trip, I found two of my glads in full bloom. Gladiolas (Gladiolus nanus) was one of my father’s favorite flowers. He became recipient of my summer blooms. Being from Holland he could appreciate flowers of any kind.

In gladiola folklore, when Apollo accidentally slew his friend Hyancinthus, gladiolas sprang from his blood. That is why gladiolas are often associated with grief, a common funeral bouquet. In folk tradition, young men wore gladiolas to the marriages of their friends symbolizing the parting of their youth. Gladiolas are also thought to be the lilies of the field that Jesus referred to in the Sermon on the Mount. In the Victorian Language of Flowers, the gladiola represents strength of character. The name Gladiolus is from the Latin gladius, meaning "small sword." Now that you have them in abundance blooming in your garden, let’s talk about some of the common diseases. What are they and what is to be done with them?

Flowers deformed: leaves and petals with white flecks: Thrips are a very common destructive pest. They are yellow to black, flying insects and feed by rasping petals and leaf surfaces, leaving silvery spots and streaks. The little rascals hide under leaf sheaths and inside the flowers. You may see thrip’s wastes as black spots on the underside of leaves. Corms are dark, sticky and rough. Treatment involves cutting away and destroying severely infested plants. To limit thrips infestation, dig corms early in fall and cut off tops before the thrips move down into the corm. Narrow-range oil, neem oil, and other low-toxicity insecticides such as insecticidal soaps or pyrethrins can be somewhat effective for temporary reduction of thrips populations if applied when thrips and damage first appear. These don't leave toxic residues, allowing at least a portion of the natural enemy populations to survive Sprays must be applied to thoroughly cover susceptible plant tissue, such as new leaf growth and buds. Native predators such as pirate bugs, lacewings, and lady beetles are to be encouraged.

Leaves, stems and buds distorted, sticky; clusters of small insects: Aphids are the likely ones here.

Infested plants have growth that may be curled, puckered or stunted. One can usually knock these off

with a strong spray of water, if not, then insecticidal soap. Destroy seriously infected plants.

Leaves mottled yellow and distorted; flowers small and faded: Fusarium yellows is a soil borne fungal disease causing foliage to turn yellow and die starting with the oldest leaves. Corms have small reddish brown lesions and may become hard and dry. Destroy these immediately and do not replant in the same area.

Flowers, leaves and stalk spotted; corms rotted: Botrytis blight is another fungal disease most prevalent in cool, damp weather. Prevention is to plant in space that gets plenty of air circulation. Water in the morning so leaves dry out before nightfall and remove all plant debris at season end and destroy.

Leaves with reddish brown spot; corms with pale to brown spots: Scab, a bacterial disease causes brown spots on blossoms. Plants rot at the bottom and fall over. Spots on corms turn dark brown with sunken centers and scabby margins. Pitch them and do not plant in the same spot the next year as the soil is infested.

Proper fall and winter corm treatment is necessary for keeping healthy corms. Dig corms about 4 to 6 weeks after flowering and preferably before the foliage normally turns yellow. Dig carefully to avoid injuring corms since wounds are often entry points for disease organisms. Remove and destroy plant tops immediately. Place newly dug corms in shallow trays or screens in a well-ventilated area. Keep at 60-70 degrees F for 2-3 weeks. Sometime during this period remove old corms and cormels. Sort out and destroy corms with signs of decay or viral symptoms. Store clean corms in paper bags at a temperature of 35-40 degrees F. Inspect corms during the winter and discard any with obvious signs of storage rot.

Gladiolas are a beautiful mid to late summer blooming flower, one to be enjoyed and shared with others. What is your favorite color?