Friday, February 02, 2007

Cacti and Succulents




Short of dropping Chicago smack into the middle of the Mohave Desert, it may be hard to conceive of cacti and succulents growing in this area. If Midwest gardeners have grown these plants at all, they were most likely grown as houseplants or greenhouse specialties.
Certainly, in order to survive a Chicago winter, the great majority of cacti and succulents would need to be overwintered indoors. But with exotic gardens and distinctive container plants attracting more and more interest, these fascinating plants are escaping the confines of the house, if only for the summer.
Since cacti and succulents tend to be desert plants, the soil and weather conditions in Chicago are a stretch. Luckily, one of the best things about container gardens is their flexibility. If a plant needs well-drained, sandy soil conditions, those conditions can be made to order in a container. If a plant needs plenty of sun but shelter from the wind, containers can be sited in exactly the right spot. And if the sun moves too far in one direction, containers can be moved accordingly.
Many of the smaller cacti and succulents are ideal for trough gardens or even portable rock gardens. Larger plants may require a container with a wheeled base to make it easier to move the plants in and out with the changing seasons. Give these plants the best living conditions possible, because, with proper care, some are exceedingly long-lived.
Some cacti and succulents are surprisingly hardy. This should come as no surprise to anyone who has visited the desert. Although the sunlight beats down fiercely during the day, often topping 100 degrees, the night falls quickly and desert temperatures plunge dramatically after dark. There are a lot of popular misconceptions about cacti. The idea that they live in sand and sun with baking heat and little rain has led to the death of many housebound pot of cactus.
To begin with, although the terms “cacti” and “succulents” are frequently used together, by definition cacti actually ARE succulents because they store water in their stems. The distinguishing feature of most cacti, of course, is their prickly needles and spines. In the case of succulents – or what most people think of as succulents – the thick, fleshy stems or leaves with their “squishy” appearance and moisture-filled interior are the defining features.
Not all cacti are desert plants – there are also “forest” cacti. These include epiphytes that cling to tropical trees, the genus Rhipsalis, which includes the trailing, jointed-looking Chain and Mistletoe cacti. This genus also includes the more familiar Easter cactus and Christmas cactus. When grown indoors, all of these species go through a period of winter rest when fertilization should be stopped and watering kept to a minimum. The soil should never be allowed to dry out completely. When these plants are dormant, a temperature of about 55 degrees F is ideal.
In summer months, forest cacti benefit from the fresh outdoor air but they should be protected from harsh sunlight – bright, filtered or part shade is ideal. Once the flower buds start to appear in summer, water these as frequently as any other container plant – do not allow the soil to completely dry out. Also, whether indoors or out, the plants will benefit from an occasional misting. When set outside in summer, forest cacti may need protection from slugs. There is one important difference between forest cacti and other container plants – once the delicate buds begin to appear, the plants should not be moved. If repotting is necessary, wait until after flowering.
The image that usually comes to mind when we hear the word “cactus” is the desert type. There are many misconceptions about the way these plants should be cared for, and to begin with it is important to distinguish them from the forest type cacti. Desert cacti, when grown as houseplants, may benefit from the fresh air but unlike their forest cousins, misting is not usually a good idea. Some cactus lovers prefer to keep their plants indoors and simply leave windows open to allow the plants to bask in the hot summer air.
Like the forest cacti, desert cacti will benefit from cool temperatures of around 50 degrees F during their winter dormancy. Many genera of cactus can survive comfortably at 40 degrees F while they are dormant. If these cacti are moved to a garage or greenhouse during their dormant period, place them where they will still be exposed to sunlight – bright sun, but not hot.
Watering needs vary during dormancy and flowering periods. Desert cacti need more water starting in the spring, and water as any other container plant during the summer. By late summer, watering should be reduced in stages leading into fall/winter dormancy, still making sure the plants are not allowed to completely dry out. Overwatering cacti in water or underwatering them in summer can lead to a variety of problems including a number of stem rot diseases. Other problems can occur if cacti are allowed to get excessively warm in winter or if they get insufficient sun in summer.
When repotting is necessary, do not move the plant into a much larger pot – it is better not to allow excess space around the roots. Be careful about pruning cactus, except in the case of damaged stems. Cacti bloom on old growth, and encouraging a cactus to bloom is not always easy. Keeping the plants somewhat rootbound seems to promote the blooming process.
Desert cacti need plenty of sun – indoors or out, during periods of active growth and during winter dormancy. At the same time, during the dog days of summer it may benefit these cacti to give them a little protection from the hottest afternoon sun.
There are far too many types of desert cacti to list or describe them all. Some of the more bizarre-looking cacti include the brain cactus (Echinofossulocactus zacatecasensis), the spiky sun cactus (Heliocereus speciosus), and the descriptive bunny ears cactus (Opuntia microdasys). The genus Opuntia includes several familiar-looking upright forms of cactus, while Rebutia, Parodia and Mammillaria are mostly globular in form. Echinopsis has both globular and upright forms, while the Red Cap cactus, Gymnocalcium milhanoichii var friedrichii, is easily recognizable by its distinctive round orange “stem” that are grafted onto a green base.
Succulents are generally easy to grow, as indoor or outdoor plants. When grown indoors, it is important to give them as much fresh air and “outdoor time” as possible when the weather is mild. Like desert cactus, these plants need a lot of sun but may benefit from a little protection when the summer sun is at its peak. Cool temperatures, a bright but cool spot and occasional watering are all that is necessary to provide during winter dormancy. Water as any other container plant during the summer, reducing water gradually as summer turns into fall. Whether grown as indoor, outdoor or greenhouse plants, succulents need a period of winter dormancy in order to rest and to ensure flowering. Sunshine and fresh air in summer, moist but well-drained soil, shelter from the hottest sun, and bright but cool winter conditions are about all that is required to keep these plants happy for years.
Cacti and succulents are ideal for trough gardens because they grow under similar conditions (which can be made to order in a large trough) and a trough can be situated on a stand that brings the garden closer to eye level. The amazing detail in some of the small cactus and succulent species has to be seen up close to be truly appreciated. A large, somewhat flat, well-drained container can also be adapted to cacti and succulents. Use potting soil that has been premixed especially to meet the needs of cacti and succulents, for best results. A slow-release fertilizer especially designed for cacti and succulents may be applied in spring, if necessary, but be careful not to overfertilize, or to add fertilizer late in the season.
Interesting and/or attractive succulents include Aeonium arboreum (particularly var. atropurpureum ‘Schwartzkopf’), the genus Agave (including the century plant, which blooms once every 100 years), the large and varied genus Aloe (a popular first aid lotion and sunburn treatment), Argyroderma, Conophytum, Crassula, Cotyledon, Delosperma, Dudleya, the roseate forms of Echeveria, succulent species of Euphorbia (as opposed to perennial Euphorbias), Faucaria, Fenestraria, Furcraea, Gasteria, Gasworthia, Graptopetalum, Haworthia, Hechtia, Hoya, Jovibarba, Kalanchoe, Lampranthus, Lithops, Orostachys, Othonna, Pachyphytum, Pachyveria, the annual flowering Portulaca grandiflora, Puya, stonecrop Sedum, Sempervivum (Hens and Chicks), Senecio and Yucca (also called Adam’s Needle).
A trough garden or a collection of containers featuring cacti and succulents can be a good introduction to these fascinating plants. Don’t just sit them on a shelf to gather dust, though – put them out on the deck or in the garden where they can be seen and enjoyed. Treat them as you would any container plant in summer, bringing them indoors and allowing them to gradually go dormant as winter approaches. A little care and attention will keep these plants alive and well as long or longer than the perennials in your garden.

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File Name: Cactiandsucculents
Word Count: 1,527

Originally published in The Landscape Contractor magazine
Photos by Becke Davis

SOURCES:

“Creating the Tropical Look in the Midwest Garden,” by Gary A. Anderson, Ph.D., The Ohio State University Agricultural Technical Institute, September 2004, The Buckeye, ONLA, Columbus, OH

“Hens and Chickens,” from “Gardening with Gary,” www.recipegoldmine.com/gardengary/gg101.html

“Succulents for the Contemporary Garden,” by Yvonne Cave, 2003, Timber Press, Portland, OR

“Foliage,” by David Joyce, 2001, Trafalgar Square Publishing, North Pomfret, VT

“The New House Plant Expert,” by Dr. D.G. Hessayon, 1991, PBI Publications, Waltham Cross, Hertfordshire, England

“Greenhouse Plants,” Elaine Ratner and James L. Jones, 1990, Ortho Books, Chevron Chemical Co., San Ramon, CA

“The New Exotic Garden,” by Will Giles, 2000, Octopus Publishing, London, England

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