Dahlia 'Bishop of Llandaff'

Engels: Bishop Dahlia

bulbAsteraceae

Dahlia 'Bishop of Llandaff' (Dahlia 'Bishop of Llandaff') is a bulb from the Asteraceae family that grows up to 110cm tall. This plant thrives in full sun and requires moderate maintenance. Blooms in autumn and summer with red flowers and attracts bees and butterflies.

Hoogte

80–110 cm

Breedte

40–60 cm

Zonligging

full sun

Waterbehoefte

moderate

Grondsoort

loam, sandy soil

Onderhoud

moderate maintenance

Bloeitijd

autumn, summer

Bloemkleuren

red

Ecologische waarde

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Verzorgingskalender

Taak	Jan	Feb	Mrt	Apr	Mei	Jun	Jul	Aug	Sep	Okt	Nov	Dec
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Care tips

Planting

Bishop of Llandaff dahlias are grown from tubers, not true bulbs, and must be planted after all risk of frost has passed. In temperate Europe, April and May are the ideal months, once soil temperatures have warmed to at least 10°C. Choose a position in full sun with shelter from strong winds, as the tall stems can reach 80–110 cm and may snap in exposed sites. Soil preparation is critical. Dahlias thrive in fertile, well-drained loam or sandy soil. Dig over the planting area to a spade's depth and incorporate plenty of well-rotted compost or manure a few weeks before planting. Avoid heavy clay that stays waterlogged, as tubers will rot. If your soil is heavy, work in horticultural grit to improve drainage. Plant tubers horizontally about 10–12 cm deep with the old stem or "eye" (the growing point) facing upwards. Space them 50 cm apart to allow for their mature spread of 40–60 cm and good air circulation, which helps prevent fungal diseases. If you're planting in rows, keep at least 50 cm between plants in all directions. Insert a sturdy bamboo cane or support stake at planting time, positioning it a few centimetres from the tuber to avoid piercing it later when roots have developed. Water the tubers in lightly after planting, but don't saturate the soil—tubers can rot if kept too wet before shoots emerge. Once growth appears, water more regularly. A 5 cm layer of mulch around the base will suppress weeds and retain moisture through summer.

Pruning

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.

Maintenance

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.