- Species and varieties: Petunia is a genus of 20 species of flowering plants of South American origin. The most common species used in gardening is Petunia × atkinsiana, which is a hybrid of Petunia axillaris and Petunia integrifolia. White petunia varieties include 'White Madness', 'Easy Wave White', and 'Daddy White'.
- Hybrid or heirloom: Petunias are available in both hybrid and heirloom varieties. Hybrids like 'Wave' series are bred for specific traits such as color, size, and disease resistance. Heirloom varieties are open-pollinated and can be grown from seeds saved from the previous year's plants.
- Pruning and training: Regular deadheading (removal of spent flowers) encourages continuous blooming. Pinching back the stems can promote bushier growth. Petunias do not require extensive pruning but benefit from occasional trimming to maintain shape and vigor.
- Fertilization needs: Petunias are heavy feeders and benefit from regular fertilization. Use a balanced, water-soluble fertilizer every 2-3 weeks during the growing season. Slow-release fertilizers can also be used at planting time to provide a steady supply of nutrients.
- Hardiness zones: Petunias are typically grown as annuals in USDA hardiness zones 9-11. In cooler climates, they are grown as annuals or in containers that can be brought indoors during colder months.
- Climate requirements: Petunias thrive in full sun and require at least 5-6 hours of direct sunlight per day. They prefer well-drained soil and moderate watering. They can tolerate a range of temperatures but perform best in mild to warm climates.