From a botanical perspective, gladiolus plants reproduce and persist through a specialized underground storage structure called a corm, which is a swollen, solid stem. Each growing season, the original "mother" corm exhausts its energy reserves to fuel the growth of the foliage and flower spike. Simultaneously, it directs energy downward to form a new, larger "daughter" corm right on top of itself. Additionally, numerous tiny, pea-sized baby corms, known as cormels, develop around the base of this new corm. These cormels are your key to multiplying your gladiolus collection. They are clones of the parent plant, genetically identical, ensuring the preservation of the specific flower color and variety.
The ideal time to divide and transplant gladiolus cormels is in the autumn, after the plant has completed its annual growth cycle. The crucial signal is the foliage. Once the leaves have turned yellow and begun to die back, photosynthesis has ceased, and the plant has transferred all its energy reserves back into the underground storage structures. This process has fully matured the new daughter corm and the attached cormels. Gently dig up the entire cluster of corms, taking care not to slice through them with your spade. Shake off the loose soil to reveal the structure: you will find the old, flattened mother corm at the base, the new plump corm on top, and the small cormels attached around its base.
To separate the cormels, gently break them away from the new corm by hand. They should detach easily. Discard the old, withered mother corm. At this stage, the cormels have a hard, protective coat. This coat is vital for preventing desiccation during storage. Place the harvested daughter corm and the cormels in a warm, dry, and well-ventilated location out of direct sunlight for a process called curing. This typically takes two to three weeks. Curing allows the corms and cormels to dry thoroughly, which seals the outer surface and helps prevent rot caused by fungal or bacterial pathogens during storage.
After curing, the cormels must be stored properly to remain viable until spring. Place them in a breathable container such as a paper bag, mesh bag, or a box filled with dry peat moss or vermiculite. Store them in a cool, dark, dry location with good air circulation and temperatures between 35-45°F (2-7°C). This cool period is a form of dormancy that mimics winter conditions. When the danger of frost has passed in the spring, the cormels are ready for planting. Soaking them in lukewarm water for a few hours before planting can help rehydrate them and encourage quicker germination.
Plant the prepared cormels about one inch deep and two inches apart in well-draining soil with full sun exposure. It is important to manage expectations; cormels are juvenile propagation units. In their first growing season, they will not flower. Their sole purpose is to photosynthesize and build up their energy reserves to form a larger, flowering-sized corm. Keep them well-watered and weeded throughout the summer. By autumn, the foliage will die back again. When you dig them up, you will find that each cormel has been replaced by a new, larger corm, though likely still not of flowering size. Repeat the storage process and plant them again the next spring. After one or two more seasons of growth, these corms will have stored enough energy to finally produce a magnificent flower spike.
