Growing Bishop Dahlia in a pot

Bishop of Llandaff has moderate water needs. During active growth from late spring through summer, water regularly—typically once or twice a week in dry spells—to keep the soil evenly moist but never waterlogged. Dahlias are prone to powdery mildew if foliage stays wet, so water at the base rather than overhead, ideally in the morning. In autumn, as flowering slows, reduce watering frequency. Feeding is essential for strong growth and abundant blooms. Once shoots emerge in May, apply a balanced general-purpose fertiliser. Switch to a high-potassium tomato feed in June and July to promote flowering; apply every two weeks according to the manufacturer's instructions. Stop feeding by late August to allow stems to harden before winter. Maintain a 5 cm layer of organic mulch around the base throughout the growing season to conserve moisture and suppress weeds, but keep it clear of the stems to prevent rot. Slugs and snails are the main enemy, especially when shoots first emerge in spring. Use organic pellets, beer traps, or patrol at dusk. Earwigs can damage flowers; trap them in upturned pots stuffed with straw placed on canes. Aphids may cluster on young growth—squash by hand or spray with soapy water. Powdery mildew can appear in dry summers; ensure good spacing and avoid overhead watering. In zone 8a and colder, lift tubers after the first frosts and store as described in the pruning section. In milder coastal gardens, you may leave tubers in situ under a 15 cm layer of mulch, though lifting is safer in wet winters.