Conventional wisdom says that plants need roots to survive. Yet, we regularly receive healthy looking orchids from clients which have few, if any, roots. Apparently, general horticulture rules do not apply to orchids.
Back in the 1920’s when corsages were the fashion in America, cut flower nurseries imported cattleya plants by the tens of thousands from the jungles of South America. Each orchid was removed from its host tree with a machete and nearly all the roots were lost in the scuffle. The hapless epiphytes were then slung into burlap bags for a weeks-long voyage at sea.
Upon arrival in the States, growers promptly potted the cargo and waited. Within a month or so, fresh roots sprouted and burrowed straight into the media. The plants were then watered feverishly to further encourage the roots which nearly filled up each pot. Before long, robust pseudobulbs had emerged, each capable of producing impressive sprays of corsage-size blooms.
Resilience is a hallmark of orchids that have pseudobulbs because these plant storage organs hold food and water for periods of drought. Even without hydration or even roots, these plants can survive for some period of time. The key is repotting the orchids before they sprout new roots so that the plants can get ‘established’ prior to blooming. The older roots are of lesser importance and are not absolutely required. Other popular orchids that have pseudobulbs and behave similarly include Cymbidiums, Dendrobiums, and Oncidiums.
Surprisingly, orchids that do not have pseudobulbs to store water can also survive without roots in the short run. Phalaenopsis, for example, sometimes find themselves sitting in water-logged decorative pots with no drainage holes. Though the roots were dead within a week, the flowers continue to look fine for a month or more.
Hobbyists are alerted to the problem if the blooms fold prematurely yet no long term damage has occurred as long as the leaves remain perky. Prompt repotting usually restores full plant vigor for next year.
In general, orchids need a strong root system leading up to flowering but can be laissez-faire in the short run afterwards. Even the jungle cattleyas, whose roots were cut off intentionally, rebounded quickly once they were repotted. Understanding the timing of root growth is essential to mastering the hobby.