‘Black and Bloom’ Salvias are popular ornamental plants known for their striking deep blue flowers and dark stems. Propagating them allows gardeners to create more plants from existing ones, expanding their garden displays or sharing with others.
Why and When to Propagate
Propagating ‘Black and Bloom’ Salvias saves money and expands your garden. This also ensures a continuous supply of this variety, especially useful where it’s grown as an annual.
The best time for propagation depends on the method. Stem cuttings are effective in late summer, early fall, or when the plant is actively growing in spring or early summer. For seeds, sow them in spring after the last frost, allowing time for establishment before cold weather.
Methods of Propagation
Stem Cuttings
Propagating ‘Black and Bloom’ Salvia from stem cuttings creates new plants genetically identical to the parent. Select healthy, non-flowering stems, ideally in the morning when the plant is well-hydrated.
Prepare cuttings 2 to 6 inches (5-15 cm) long. Using a sharp, clean knife or secateurs, cut just below a leaf node, the point where leaves attach to the stem and where rooting cells are concentrated. Remove all leaves from the lower half of the cutting to prevent rotting. For larger-leaved varieties, cutting the remaining leaves in half can reduce moisture loss and allow more cuttings to fit in a pot.
Dipping the cut end of the stem into a rooting hormone powder or gel is highly recommended to encourage root development and significantly increase success. Prepare a well-draining rooting medium, such as a mix of perlite, vermiculite, and potting soil.
Insert cuttings into the pre-moistened medium, ensuring the bare stem is buried and leaves are above the soil line. You can place multiple cuttings in one pot, spacing them for air circulation. Gently firm the medium around each cutting for good contact.
To maintain high humidity, cover the pot with a clear plastic bag or place it in a propagator, ensuring the plastic does not touch the foliage. Place covered cuttings in indirect light at around 68°F (20°C). Cuttings typically root within 3 to 6 weeks.
Seed Propagation
Propagating ‘Black and Bloom’ Salvias from seeds is an option, though it may not always produce plants identical to the parent due to genetic variation. Collect seeds from mature plants once the calyx (the cup-like structure at the base of the flower) has turned brown and the seeds inside have darkened. Prepare seed trays with a well-draining seed-starting mix.
Sow seeds directly on the soil surface, as Salvia seeds often require light for germination. Do not cover them, but gently press them into the medium for good contact. Keep the soil consistently moist but not waterlogged, and maintain a warm environment, ideally around 75°F (24°C). Germination typically takes 5 to 30 days.
Caring for New Salvia Plants
Once ‘Black and Bloom’ Salvia cuttings have rooted or seedlings have developed true leaves, they require specific care. After rooting, gradually acclimate young plants to outdoor conditions through hardening off. This involves slowly exposing them to increasing periods of sunlight, wind, and outdoor temperatures over several days before transplanting.
When plants are robust and frost danger has passed, transplant them into larger pots or directly into the garden. Choose a sunny location with well-drained soil, as ‘Black and Bloom’ Salvias prefer full sun and tolerate partial shade. Prepare the new planting site with compost to encourage healthy root development.
Newly transplanted salvias need consistent watering to establish root systems. Water deeply 2-3 times per week until established, then reduce to moderate watering, allowing the soil to dry slightly between waterings. Avoid overhead watering to minimize fungal issues. While young plants benefit from initial fertilization, established ‘Black and Bloom’ Salvias are low-maintenance and thrive with less frequent feeding.
Common Propagation Challenges
Gardeners may encounter several challenges when propagating ‘Black and Bloom’ Salvias. Cuttings may fail to root due to rotting from excessive moisture or drying out from insufficient humidity. Proper drainage in the rooting medium and consistent, but not overly wet, humidity levels can prevent this.
Slow growth in new plants can stem from inadequate light, as ‘Black and Bloom’ Salvias require ample sunlight for vigorous development. Placing young plants in a spot receiving at least six hours of direct sunlight daily can help. Pest issues, such as whiteflies, fungus gnats, or thrips, can also affect young plants. Regularly inspect new growth and address infestations promptly with appropriate organic solutions to maintain plant health.