Bishop of Llandaff dahlia

Sun

Full sun; light afternoon shade can help in very hot climates.

Water

Water deeply when the top few inches of soil dry out; keep moisture reasonably even during growth without leaving the roots waterlogged.

Soil

Fertile, well-drained soil enriched with compost; avoid ground that stays wet in winter.

Height

3-4 ft (0.9-1.2 m)

Spread

1.5-2 ft (0.45-0.6 m)

Flowers

Scarlet-red, semi-double flowers with exposed golden-yellow centres, from midsummer until the first frost.

Foliage

Divided, toothed leaves in dark bronze-purple to nearly black; foliage dies back with frost.

Growth

Fast during the growing season.

Care needed

Medium

• Pollinators
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Moderate

Toughness

Fairly tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1 ft (0.3 m)

2. After 1 year

   2.2 ft (0.68 m)

3. After 2 years

   3 ft (1.1 m)

   full size

About 2 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Mildly toxic: may upset a stomach

Growth rate

Fast

• Plant after frost danger has passed and the soil has warmed; place the tuber crown just below soil level.
• Put stakes or a support ring in place at planting, before stems become tall and brittle.
• Water sparingly before shoots emerge, then deeply during dry weather without saturating the soil.
• Feed container plants regularly with a flowering-plant fertiliser; avoid excessive nitrogen, which encourages leaves at the expense of flowers.
• Mulch after the soil warms, keeping mulch clear of the stems.
• Where winters are cold or wet, lift tubers after frost blackens the foliage and store them somewhere cool, frost-free and ventilated.

Pruning. Pinch out the growing tip when shoots are about 12 in (30 cm) tall to encourage branching, and remove faded flowers back to a strong leaf joint throughout flowering. After frost blackens the foliage, cut stems down before lifting or protecting the tubers.

Early spring

Check stored tubers for rot or shrivelling; pot up sound tubers under frost-free cover for an earlier start.

Late spring

Harden off growing plants and plant outside after the last frost; install supports.

Early summer

Pinch young shoots, tie stems loosely to supports and mulch moist soil.

Summer

Water during dry spells, feed container plants and remove faded flowers regularly.

Autumn

Continue deadheading until frost; label plants before their foliage dies back.

Late autumn

Lift tubers in cold or wet regions after foliage is frosted; in mild, well-drained gardens, cut back and apply a protective mulch.

Winter

Inspect stored tubers periodically, removing rotten material and preventing prolonged dampness or severe drying.

• Plant through the middle of a sunny mixed border, where dark foliage contrasts with green-leaved perennials.
• Combine with orange flowers and purple salvias for a strong late-summer hot border.
• Use in a large patio container with sturdy support and reliable watering.
• Repeat small groups among ornamental grasses for scarlet accents from summer into autumn.

Garden styles it suits: Cottage garden, English country, Arts and Crafts, Hot border, Pollinator garden and Modern courtyard.

Plant it with: Purple salvia, Verbena bonariensis, Crocosmia, Sneezeweed, Purple coneflower and Switchgrass.

Wildlife: The exposed flower centres provide pollen and nectar for bees and other flower-visiting insects; they are more accessible than those of densely double dahlias.

• Slugs and snails can destroy emerging shoots: inspect at dusk, remove hiding places and use barriers or locally approved controls where needed.
• Aphids cluster on young growth: rinse them off with water and encourage ladybirds and other predators; use insecticidal soap if necessary.
• Earwigs may chew petals: check flowers and nearby hiding places, and trap and relocate them if damage becomes troublesome.
• Tubers rot in cold, wet soil or damp storage: improve drainage, avoid watering dormant tubers and store lifted tubers frost-free with ventilation.

Dahlias are mildly toxic to cats and dogs if chewed, potentially causing stomach upset; contact may also cause mild skin irritation. Leaves, stems, flowers and tubers should be kept out of their reach. They are not generally regarded as poisonous to people, although sap can irritate sensitive skin. Toxicity to horses is not well established, so do not offer plants or garden clippings as feed.

• Bishop of Auckland dahlia (Dahlia 'Bishop of Auckland')

  Also has very dark foliage, but its flowers are usually single and deeper crimson-red rather than the scarlet, semi-double flowers of 'Bishop of Llandaff'.

• Bishop of Oxford dahlia (Dahlia 'Bishop of Oxford')

  Has similarly dark foliage but orange flowers rather than scarlet-red flowers.

Dahlia honours the Swedish botanist Anders Dahl, while 'Bishop of Llandaff' was named for the bishop of the Welsh diocese of Llandaff.

Propagation. Divide tuber clumps in spring, ensuring each division has a piece of crown with a visible bud; an isolated tuber without a crown bud will not grow. Basal cuttings taken from fresh spring shoots also retain the cultivar. Seedlings will not reliably come true.

Accepted botanical name

Dahlia

Sources: GBIF (CC BY 4.0). The care and design notes are LandscapeGPT's own.