The colorful blooms of snapdragons are a popular addition to garden beds and cut-flower arrangements. These hardy, cool-season annuals or short-lived perennials can be easily multiplied using two primary methods: propagation from seed and from stem cuttings. Whether aiming to grow many plants from seed or preserve the traits of a favorite hybrid, understanding these techniques is key to success. This guide details the practical steps needed to propagate these flowers.
Starting Snapdragons from Seed
The most common way to begin growing snapdragons is by sowing seeds indoors, a process that should start approximately 8 to 10 weeks before the last expected frost date in your region. This early start is beneficial because snapdragons develop slowly, allowing for a longer flowering season once they are transplanted outdoors. Begin by filling clean seed trays with a sterile, fine-textured seed-starting mix.
Snapdragon seeds are small and require light for successful germination, meaning they should not be covered with soil after sowing. Instead, gently press the seeds onto the surface of the moistened medium to ensure good contact. Covering the tray with a clear plastic dome or bag helps maintain the high humidity and consistent moisture levels necessary for the seeds to sprout.
Place the trays in a location that receives bright light, such as beneath a dedicated grow light for about 16 hours a day. A steady temperature between 65°F and 75°F encourages germination, which typically occurs within 7 to 14 days. Once the seedlings develop their first set of true leaves and are large enough to handle, carefully separate and transplant them into individual small pots or cell packs.
Multiplying Plants Using Stem Cuttings
Propagating snapdragons from stem cuttings is the preferred method when you want to create genetically identical clones of a specific plant, especially a prized hybrid cultivar. This vegetative technique bypasses the genetic variability that occurs when growing from seed, ensuring the new plants possess the exact color, height, and bloom characteristics of the parent. The ideal time to take cuttings is late summer or early fall, or when you are pinching back young plants to encourage branching.
Select a healthy, non-flowering stem section about three to four inches long, making a clean cut just below a leaf node, which is where new roots are most likely to form. Remove the lower leaves from the cutting, leaving only two or three sets of leaves at the top, which helps reduce water loss. Dipping the cut end into rooting hormone powder or gel is recommended to increase the chances of root development.
The prepared cutting should be inserted into a moist, well-draining rooting medium, such as a mix of peat and perlite. A high-humidity environment is necessary for rooting success, so covering the container with a clear plastic bag or placing it in a propagator helps trap moisture. Keep the cuttings in a location with bright, indirect light; small white roots should begin to emerge within a few weeks, indicating the start of a new plant.
Transitioning Young Plants Outdoors
Once snapdragon seedlings or rooted cuttings are well-established, they must undergo a gradual process called “hardening off” before being permanently planted outside. This step acclimates the tender indoor-grown plants to direct sun, wind, and fluctuating temperatures, which prevents severe transplant shock. The hardening off process should span 7 to 10 days, beginning by placing the plants outdoors in a sheltered, shaded spot for just one or two hours.
Each day, gradually increase the amount of time the plants spend outside, exposing them to progressively longer periods of sunlight and eventually leaving them out overnight. This slow introduction allows the plant tissues to thicken and adjust, preparing them for the garden. Once this period is complete and the danger of a hard frost has passed, the snapdragons are ready for final planting.
The chosen garden site should offer full sun exposure and feature rich, well-draining soil, as snapdragons do not tolerate standing water. When transplanting, dig a hole slightly larger than the root ball, gently loosen any tightly bound roots, and place the plant at the same depth it was growing in its pot. Maintain a spacing of 6 to 12 inches between plants to allow for ample air circulation. Immediately after planting, water the area thoroughly to settle the soil around the roots, and consider applying a balanced, slow-release starter fertilizer to support initial establishment.