Freesias are warm-climate flowers that are not tolerant of cold temperatures. Though commonly referred to as bulbs, freesias actually grow from corms, which are solid, underground storage stems. In climates where the ground freezes, these tender corms cannot survive the winter outdoors and must be lifted and stored. Proper storage is necessary to ensure the corms remain healthy and retain the energy needed to produce colorful flowers the following spring.
Determining When to Lift Freesia Corms
The timing for lifting freesia corms is determined by the senescence of the foliage. It is important to wait until the leaves have completely yellowed and died back, turning straw-like. This indicates that the plant has finished its active growth and transferred maximum energy reserves back into the corm for dormancy. Removing the corms while the foliage is still green prevents this energy transfer, potentially resulting in weak plants and poor flowering the following year. The ideal time to lift them is typically in the early autumn, just before the first hard frost is predicted to damage the dormant corms.
Cleaning and Curing the Corms
Once the corms are gently dug from the soil, immediate preparation is required to prevent mold and decay during storage. Carefully remove the majority of the attached soil, taking care not to damage the corm’s outer skin. Trim back any remaining dead foliage and roots close to the corm. This initial cleaning removes potential sources of moisture and pathogens that could compromise the corm’s health.
The curing process is necessary to completely dry the corms and prepare them for dormancy. Curing involves placing the corms in a warm, dry, and well-ventilated location, away from direct sunlight. A temperature range between 77°F and 86°F (25°C and 30°C) is recommended, as this warmth helps ripen the corms and encourages flower bud formation. This phase typically lasts for one to two weeks until the corms feel hard and dry to the touch.
After the initial curing, inspect each corm for signs of damage or disease, such as soft spots or discoloration, and discard any that appear unhealthy. Gently separate the smaller offsets, known as cormels, which grow from the main corm. These cormels can be stored and planted later to grow new plants, though they may take a couple of seasons to reach flowering size.
Selecting the Right Storage Environment
Following the curing process, the corms are ready for their long-term dormant storage, which requires a specific environment to maintain their viability. The optimal long-term storage temperature is cool but consistently above freezing, ideally maintained between 50°F and 55°F (10°C and 13°C). A basement, garage, or cool shed that remains frost-free throughout the winter is an appropriate location for this secondary storage phase. The storage environment must also be dry and offer good air circulation to prevent the buildup of humidity, which is a primary cause of fungal growth and rot.
The corms should be stored in a medium that absorbs any residual moisture while allowing air to flow freely around them. Suitable options include placing them inside paper bags, mesh bags, or old nylon stockings. Alternatively, you can layer the corms in a box and cover them with materials like dry peat moss, vermiculite, or sawdust. Avoid using sealed plastic containers, as these trap moisture and severely limit the necessary airflow.
Check on the stored corms once a month throughout the winter dormancy period. This periodic check allows you to look for signs of mold, shriveling, or pest damage. If any corms show mold, remove them immediately to prevent spread, and refresh the storage medium or dry out the environment further. If the corms appear excessively shriveled, the storage area may be too dry, requiring a slight increase in ambient humidity.