Collecting Seeds of Mountain Laurel
Kalmia latifolia, or mountain laurel, blooms May through June, with bursts of flowers lasting up to three weeks. Each flower develops into a seed capsule. Mountain laurel seed propagation requires conditions that match the wild ones in which the seeds will germinate. These include site, temperature, soil, and moisture. Growing mountain laurel from seed starts with harvest and acquisition. After bloom, the plant develops five chambered, globe-shaped capsules. When ripe and dried, they burst open and release seeds in autumn. Strong winds disperse the seed to other sites. When seeds reach a favorable location and undergo several altering conditions, they will grow. For instance, the seeds of mountain laurel require cold stratification over the winter to break dormancy and germinate in spring. The amount of moisture and light will also increase germination time. Cut pods and place them in a paper bag to harden further. Then shake the bag to allow seeds to fall into the bottom of the bag.
When to Sow Mountain Laurel Seeds
Once you have harvested seeds, they should be sown almost immediately outdoors to allow the cold experience. Alternatively, you can sow them in containers and place in the refrigerator or simply chill seeds in a closed bag and plant in spring. The seeds need to experience temperatures of at least 40 degrees Fahrenheit (4 C.) for 3 months. When temperatures warm to at least 74 Fahrenheit (24 C.), germination can occur. Growing mountain laurel from seed also requires light for germination as well as average moisture. Seeds are surface sown to allow for the light requirement.
How to Plant Mountain Laurel Seeds
In addition to surface sowing, cold pre-treatment, and light, mountain laurel seed propagation also needs an exacting growing medium. While potting soil might suffice, experts recommend moistened sand to germinate the seed. Germination takes 1 to 2 weeks. Once germinated and achieving their second set of true leaves, transplant seedlings to humus rich soil. You can make this by mixing half potting soil and half compost. Seedlings must be kept moist, but not soggy, at all times. Before planting them outdoors, pre-condition them by hardening them off for several days. Plant outdoors after all danger of frost has passed in a sunny location with moist but well-draining soil.
