Bishop Dahlia in November: monthly care

Bishop of Llandaff benefits from regular deadheading rather than heavy pruning during the growing season. From summer through autumn, remove spent blooms every few days by cutting back to the first set of leaves or side shoot. This encourages continuous flowering and prevents the plant from putting energy into seed production. Use clean, sharp secateurs to make neat cuts and reduce the risk of disease. In October or November, after the first frosts have blackened the foliage, it's time to cut back the stems. Frost-damaged dahlias look unsightly and the dying foliage can harbour pests and diseases over winter. Cut the stems down to about 10–15 cm above ground level. This short stub helps you locate the tubers if you're lifting them and protects the crown from damage. In zone 8a gardens, where frosts are lighter, some gardeners leave tubers in the ground over winter under a thick mulch. If you choose this approach, cut back the stems as described but leave the crown intact. In colder or wetter areas, it's safer to lift the tubers. Wait a week after cutting back to allow the stems to dry slightly, then carefully dig around the clump with a fork, lifting the entire root ball. Shake off excess soil, trim any damaged roots, and allow tubers to dry upside down for a few days before storing in barely damp compost or sand in a frost-free shed or garage. Inspect stored tubers monthly and discard any showing signs of rot.

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.