Dahlia Bishop of Oxford

Dahlia ‘Bishop of Oxford’ is a real head-turner, combining deep, dramatic foliage with glowing flowers that seem to shine in summer sunshine. It produces rich scarlet-red blooms (single to semi-double) set against striking dark purple-bronze leaves, creating a bold contrast that looks incredible in borders and patio pots. This variety flowers generously from midsummer right through to the first frosts, making it a brilliant choice for long-lasting colour.

As well as being a garden showstopper, ‘Bishop of Oxford’ is also a pollinator favourite—the open-centred flowers are easy for bees and butterflies to access. It’s perfect for mixing into cottage-garden planting, pairing beautifully with ornamental grasses, Salvias, Verbena bonariensis and other late-summer favourites.

Planting Instructions

When to Plant:

Plant Dahlia tubers in spring. For the earliest flowers, start tubers in pots indoors from March to April, then plant out once the risk of frost has passed. If planting directly outside, wait until late spring when the soil has warmed.

Where to Plant:
Choose a sunny, sheltered position with fertile, well-drained soil. Dahlias are ideal for mixed borders, cutting gardens and patio containers. They love warmth and perform best in full sun.

How to Plant:

• Depth: Plant tubers about 10–15 cm (4–6 inches) deep, with the old stem (or growing point) facing upwards.
• Spacing: Space plants 45–60 cm (18–24 inches) apart, depending on the final size.
• Soil Prep: Enrich the planting area with well-rotted compost or manure. In heavy soil, improve drainage with grit.

Watering:
Water after planting. Once shoots appear and growth is underway, keep soil evenly moist, especially in dry spells. Avoid waterlogging. Container-grown Dahlias may need watering daily in hot weather.

Aftercare Tips:

• Pinch out the growing tip once plants are around 30 cm tall to encourage bushier growth and more flowers.
• Stake taller stems if needed, especially in exposed borders.
• Deadhead regularly to keep plants flowering until autumn.
• After the first frost blackens the foliage, lift tubers and store dry and frost-free over winter, or protect in the ground with a thick mulch in milder areas.

Top Tip:
Dahlias like a “feed and water” routine. A weekly high potash feed from midsummer will keep ‘Bishop of Oxford’ pumping out flowers right up to the first frosts.

Plant Details

Flowering Period:

July - October (until first frosts)

Height:
30–36" (75–90cm)

Position:
Full sun

Tender Perennial:
Overwinter tubers frost-free in the UK