Many plants have edible stems, such as broccoli, sweet potato, cauliflower, celery, kohlrabi, rhubarb, asparagus, bamboo, kapul, sassafras, sugar cane, leek and onion. In some cases, like broccoli, other parts of the plant are edible as well, such as the flower.
There are many plants where the primary source of food is the stem. For example, the celery stem or stalk is the most common part of the vegetable that people eat, although both the bulb and the seeds are edible as well. The red rhubarb stalk is also another example of an edible stem. In other plants, the stem is a secondary source of food. Broccoli falls under this category. The flower of the broccoli plant is the main form of nutrition, but the stalks are edible as well. Sweet potato stem tips and shoots are popular in many parts of the world and rich in protein, although some varieties are too bitter to eat. Radish is another plant that has many edible parts. In fact, the whole thing is edible, although it is grown largely for the root.
Texas A&M University explains that these secondary edible parts of plants, like stems, are overlooked because they often have a strong flavor or strange texture. Sometimes, they are not even edible, or slightly poisonous, unless they are cooked first.