Ranunculus, commonly known as the Persian Buttercup, multiplies naturally, increasing your stock of these popular cut flowers. Multiplication occurs primarily through specialized underground storage organs called corms. While often grown as a cool-season annual, ranunculus is a tender perennial in warmer zones where the corms can survive winter in the ground. Understanding corm biology is the first step toward successfully increasing the number of plants you can grow in subsequent seasons.
Understanding the Ranunculus Corm
Ranunculus plants grow from corms, which are fleshy, underground structures storing energy and nutrients. A dried corm is easily recognizable by its shriveled, claw-like appearance, fueling initial spring growth and the production of blooms.
As the plant grows and flowers, the original corm uses its stored energy and begins reproduction. It forms new, smaller corms, often called offsets or daughter corms, which cluster around the base of the parent corm. This is the plant’s natural mechanism for multiplication.
A single healthy parent corm may yield five to ten new corms under optimal conditions. This multiplication occurs underground while the plant is actively growing and finishes as the foliage begins to die back. The new corms are genetic clones, ensuring the next generation has the same flower color and form.
Managing Corm Offsets for Increased Stock
To successfully harvest this natural increase in stock, manage the corms during the plant’s dormancy phase. The timing for lifting the corms is important: wait until the foliage has naturally yellowed and died back, typically in late spring or early summer. This signals that the plant has stored maximum energy in the new daughter corms for the next cycle.
Carefully lift the corms from the soil using a garden fork, noting they are usually located only a couple of inches below the surface. Gently brush off excess soil, but avoid washing the corms, as moisture encourages rot. The next step involves curing, or drying, the corms thoroughly to prepare them for storage.
Spread the corms in a single layer on a mesh tray or newspaper in a shaded, well-ventilated area for one to two weeks. They must become completely dry and firm before storage; residual moisture causes storage failure due to mold or rot. Once fully cured, gently separate the new offsets from the parent corm, completing the multiplication process.
For successful overwintering, place the dried, separated corms into breathable containers, such as mesh bags, paper bags, or boxes filled with dry materials like peat moss or vermiculite. Store them in a dark, dry location with good airflow, maintaining a cool temperature, ideally between 40°F and 60°F. Proper storage keeps the corms dormant and viable for six to nine months, ready for replanting the following season.
Multiplication Through Seed Propagation
While corm offsets are the most practical way to increase stock, ranunculus can also be propagated through seeds. Seed propagation is a slower, more involved method, often used by hybridizers or for growing a large quantity of plants from a low-cost investment. The process requires sowing tiny seeds into a seed-raising mix, keeping them lightly covered and moist.
Ranunculus seeds germinate best in cool conditions, ideally with soil temperatures around 64°F (18°C). Germination typically takes 15 to 20 days but may extend up to four weeks. Plants grown from seed require a full growing season to mature and produce small corms, which are then lifted and stored like mature corms.
Seeds collected from hybrid varieties may not grow into plants identical to the parent flower. The resulting flowers may exhibit variations in color, size, and form. This is why corm division remains the preferred method for maintaining a specific, desired variety. Seed propagation appeals to those interested in genetic variation or those with patience for a delayed flowering timeline.