Calla

CALLA - A name applied to plants of several genera of the Arum Family, especially the native water-loving herb, Calla palustris and species of the genus Zantedeschia, which are South African tuberous-rooted plants cultivated in the garden and greenhouse and often called Calla-lily.

Calla palustris (Water arum or Wild Calla) to 12 in., grows in cold bogs in the N. temperate regions. It has a white spathe, or flower-like bract, greenish outside, surrounding a yellow spadix or flower spike, which later bears a dense cluster of bright red berries. It is frequently transferred from the wild to the margin of the bog garden.

Zantedeschia aethiopica (the Calla of florists) is a sturdy bulbous plant growing to 2 1/2 ft. It also has large smooth, arrow-shaped leaves and a creamy-white flaring spathe with a pointed tip, surrounding a yellow spadix. There are a number of horticultural forms, such as vars. minor and devoniensis, both smaller than the type. The calla is much grown in greenhouses as a pot plant and for cut flowers, as a perennial outdoors in mild climates, and in the North for summer bloom in the garden, the tubers being wintered indoors. In the latter case, plant the tubers after danger of frost is over in moist ground near a pool. The plants will bloom profusely during the summer, and the tubers should be lifted before cold weather in the fall. After being rested for a month or two, they can be potted in soil made rich with well-rotted manure, placed in a fairly sunny spot in the cool greenhouse, watered daily and given an occasional watering of weak liquid manure. With this treatment they will later bloom in late winter or early spring even in a shaded spot. Plants received as gifts in winter can likewise be rested after blooming, then planted in the garden to flower in early fall.

Zantedeschia elliottiana (Golden Calla) with a rich glowing-yellow spathe and large, somewhat oval leaves, mottled or spotted with white, requires a leaner soil mixture and rather more heat than the foregoing. Pot the tubers at the end of October for March and April bloom, or in spring for winter flowers, and keep them dark and slightly dry until the roots begin to form. When they have outgrown their pots, shift them into the next size, using a fibrous soil with plenty of leafmold and no manure, and grow in a moderately warm temperature, feeding with liquid manure from the time the flower stalks appear. After the flowering season is finished, ripen off the tubers in the pots by gradually withholding water, then store in a dark, cool place.

Calla Enemies

A fungus is responsible for stunting and dry rot of calla roots, accompanied by yellowed foliage and reduction in bloom. A bacterial soft rot causes rotting of plants at the surface of the soil, blighting of leaves and a slimy decay of the corm. Discard badly diseased corms and cut out diseased areas in others. To control both dry and soft rots soak corms in approved fungicide.

If aphids are troublesome on calla leaves spray with an insecticdial-soap solution.

Black-calla is Arum palaestinum; Red-calla is a name sometimes given to varieties of Sauromatum guttatum.

Related Articles

• Caladium - CALADIUM (kah-lay’-di-um). A genus of striking, large-leaved herbs of the Arum Family, native to tropical America, and grown for their ornamental veined and marbled foliage as bedding plants, or more commonly in the greenhouse and conservatory. The principal species is Caladium bicolor, from which have been developed many varieties and hybrids with brilliantly colored and
• Acorus - ACORUS (ak’-oh-rus). The name of a few, hardy, swamp-loving herbs of the Arum Family. They have slender, grassy leaves and inconspicuous, greenish flowers on a thick spike (spadix) partly surrounded by a bract (spathe). They are often planted in the bog garden and are increased by division. Acorus calamus, the Sweet Flag, grows as high