Your primary assessment should focus on the overall health and vigor of the plant. Avoid any orchid that appears limp, wilted, or spindly. A healthy Dendrobium should have an upright, robust habit. Carefully examine the leaves, as they are excellent indicators of the plant's condition. They should be firm, turgid, and uniformly green. Reject plants with leaves that are yellowing, significantly wilted, or have black or brown soft spots, which can indicate rot or disease. Also, check for pests on both the tops and undersides of leaves; look for signs of scale (bumpy brown discs), mealybugs (white cottony masses), or spider mites (fine webbing).
The root system is the hidden engine of the orchid and is critical to its future success. If the plant is in a clear plastic pot, this task is straightforward. Healthy Dendrobium roots are firm and white or silvery when dry, turning green when wet. Gently press on the roots through the pot; they should feel solid, not hollow, mushy, or papery, which are signs of rot caused by overwatering. Some roots may naturally be growing outside the pot (aerial roots), which is perfectly normal. A dense root mass filling the pot is a sign of an actively growing, well-established plant that may soon need repotting but is fundamentally healthy.
Dendrobium orchids store water and nutrients in their thick stems, called canes or pseudobulbs. These structures are key to the plant's resilience. Select a plant with plump, fat canes that show no signs of deep wrinkling or shriveling, which indicates severe dehydration or root loss. Some wrinkling on older canes can be normal, but the newest, greenest canes should appear full and smooth. Be aware that different types of Dendrobiums have different cane structures; some are tall and thin (like the phalaenopsis-type), while others are short and chunky (like the nobile-type). Familiarize yourself with the typical form of the type you are buying.
If you are purchasing a plant in bloom or bud, this requires specific attention. Look for a plant where most of the flowers are still in bud rather than fully open. This allows you to enjoy the bloom period for much longer once you bring it home. The flower spike itself should be strong and staked upright if necessary. The buds should be plump, well-formed, and show good color. Avoid plants with buds that are yellowing, shriveled, or dropping, a condition known as "bud blast," which is often caused by a sudden change in environment (like moving from a greenhouse to a store). A plant with a strong spike and many unopened buds is an excellent choice.
