There are two main growth types in orchids sympodial (multiple stem) and the monopodial (single stem). In order to grow orchids successfully, it’s important to understand each type of growth so that you can treat them correctly.
The first growth type is sympodial. This growth type is more common among orchids. Most sympodial orchids have pseudobulbs which function as storage reservoirs for food and water. The plant will hold pseudobulbs vertically and send out new growth horizontally between the pseudobulbs. They function very much like rhizomes on terrestrial plants. Many times more than one growth at a time will be present.
The growth begins at the base of the pseudobulb and is called a “lead.” Both the shoot and roots will grow from this lead. Leaves can last for several years and provide nourishment to the plant until they turn brown and die. Even without a leaf, the pseudobulb will continue to support the plant.
Examples of sympodial orchids are Cattleya, Paphiopedilum, Oncidium, and Dendrobium.
The second growth type is monopodial. In this type of growth pattern there is one main stem which grows indefinitely from the center of the plant. Normally, the stem grows straight up and aerial roots sprout from where the stem and leaves meet. The plant will lose its leaves from the ground up, continually growing new leaves from the tip and making new roots along the stem.
Examples of monopodial orchids are Phalaenopsis and Vanda. The foliage is generally thick and leathery and grows alternately on the stem. Inflorescences rise from the stem at the base in the case of Phalaenopsis or from between leaves in the case of Vanda.