As petunias, we thrive in full sunlight. To keep us blooming all summer, ensure we receive at least 6-8 hours of direct sunlight daily. Sunlight fuels our photosynthesis process, which is essential for producing energy and vibrant blooms. If planted in shady areas, our growth slows, and flowering diminishes. For container-grown petunias, rotate pots occasionally to ensure even light exposure.
We prefer moist but well-drained soil. Overwatering can drown our roots, while underwatering stresses us, causing wilting and fewer flowers. Water us deeply when the top inch of soil feels dry, preferably in the morning. Avoid wetting our foliage to prevent fungal diseases. In hot summers, we may need daily watering, especially in containers where soil dries faster.
We are heavy feeders and require nutrients to sustain continuous blooming. Use a balanced, water-soluble fertilizer (e.g., 10-10-10) every 2-3 weeks. Alternatively, a slow-release fertilizer mixed into the soil at planting can provide steady nourishment. For prolific blooms, switch to a high-phosphorus formula (e.g., 15-30-15) mid-season to encourage flower production.
When our flowers fade, remove them promptly. Deadheading redirects energy from seed production to new blooms. Pinch or snip off wilted flowers just above the next set of leaves. For trailing varieties, trim back leggy stems by one-third to promote bushier growth and more flowers. Regular grooming keeps us looking tidy and productive.
By midsummer, we may become leggy or stop blooming vigorously. A light pruning rejuvenates us. Cut back about one-third of our stems to encourage new growth and another flush of blooms. This mimics natural grazing and stimulates lateral branching, resulting in a fuller appearance and more flowers.
Aphids, slugs, and fungal diseases like powdery mildew can weaken us. Inspect our leaves and stems regularly. Use insecticidal soap for pests and ensure good air circulation to prevent fungal issues. Avoid overcrowding and waterlogged soil, as these conditions invite problems. Healthy plants bloom more reliably.
Some of us are bred for non-stop blooming, like 'Supertunias' or 'Wave' petunias. Selecting these varieties from the start ensures a summer-long floral display. Multiflora types tolerate heat better than grandifloras, making them ideal for hot climates. Research our cultivars to match your growing conditions.
A 2-3 inch layer of organic mulch (e.g., shredded bark or straw) around our base helps retain soil moisture, suppresses weeds, and keeps roots cool in summer heat. Avoid piling mulch against our stems to prevent rot. Cool roots mean less stress and more energy for blooming.
