- Species and varieties: Dahlia is a genus of bushy, tuberous, herbaceous perennial plants native to Mexico and Central America. There are 42 species of dahlia, with hybrids commonly grown as garden plants. Popular varieties include 'Bishop of Llandaff', 'Cafe au Lait', and 'Arabian Night'.
- Hybrid or heirloom: Dahlia seeds can be both hybrid and heirloom. Hybrid dahlias are bred for specific traits such as color, size, and disease resistance, while heirloom varieties are open-pollinated and have been passed down through generations.
- Pruning and training: Dahlias benefit from regular deadheading to encourage continuous blooming. Pinching back the growing tips when the plants are young can promote bushier growth. Taller varieties may require staking to support the heavy blooms.
- Fertilization needs: Dahlias are heavy feeders and benefit from a balanced fertilizer (10-10-10) applied every 3-4 weeks during the growing season. Avoid high-nitrogen fertilizers as they can promote foliage growth at the expense of flowers.
- Hardiness zones: Dahlias are suitable for USDA hardiness zones 8-11. In colder zones, they can be grown as annuals or their tubers can be dug up and stored over winter.
- Climate requirements: Dahlias thrive in full sun and require at least 6-8 hours of direct sunlight per day. They prefer well-drained, fertile soil with a pH between 6.0 and 7.5. Dahlias need moderate watering, ensuring the soil remains moist but not waterlogged.