Garden flowers

Rudbeckia

RudbeckiaAsteraceae
Also: Black-eyed Susan, Gloriosa daisy, Rudbeckia hirta
Perennial

Perennial

One of the most reliable late-summer perennials: plant in spring and it flowers from its first year.

Part shade Water: average H6down to −20 °C 60–80 cm tall · 45–60 cm wide In a pot: yes
Flowering · UK
Flowering · Northern Italy
Flowering · Central Italy
Flowering · Southern Italy and islands

Care

Light

Full sun is best; tolerates light shade.

Water

Medium — happier in soil that doesn't dry out than most prairie daisies.

Soil

Moist but well-drained soil; copes with clay.

Pruning

Leave the dark seed heads standing over winter, then cut everything back to the base in early spring.

Feeding

Rarely needs feeding in the ground; a compost mulch in spring is enough.

Propagation

Divide clumps in spring every few years, replanting the vigorous outer pieces.

Month by month

Months change with the climate: in southern Italy tomatoes go out two months earlier than in England.

  1. MarchCut last year's stems to the base as new growth starts. how ›
  2. MayProtect young shoots from slugs. how ›
  3. OctoberLeave seed heads standing for winter structure and birds.

Months based on climate: UK. Your choice stays on this device.

  1. MarchCut last year's stems to the base as new growth starts. how ›
  2. MayProtect young shoots from slugs. how ›
  3. OctoberLeave seed heads standing for winter structure and birds.

Months based on climate: Northern Italy. Your choice stays on this device.

  1. FebruaryCut last year's stems to the base as new growth starts. how ›
  2. AprilProtect young shoots from slugs. how ›
  3. OctoberLeave seed heads standing for winter structure and birds.

Months based on climate: Central Italy. Your choice stays on this device.

  1. FebruaryCut last year's stems to the base as new growth starts. how ›
  2. AprilProtect young shoots from slugs. how ›
  3. NovemberLeave seed heads standing for winter structure and birds.

Months based on climate: Southern Italy and islands. Your choice stays on this device.

Common problems

Slugs on new growth

How to spot it. Spring shoots eaten back.

What to do. Protect emerging clumps in spring.

Powdery mildewfull sheet ›

How to spot it. White coating on leaves in dry late summers.

What to do. Mulch and water in drought; usually cosmetic.

Congested clumps

How to spot it. Fewer flowers and a bare centre.

What to do. Divide in spring.

Gloriosa daisyRudbeckia hirta

Gloriosa daisy

Treat it as an annual: sow each spring, and it gives weeks of colour until the frosts.

Full sun Water: average H3down to −5 °C 30 cm–1 m tall · 30–45 cm wide In a pot: yes
Flowering · UK
Flowering · Northern Italy
Flowering · Central Italy
Flowering · Southern Italy and islands

Care

Light

Full sun for the longest flowering.

Water

Medium — water in dry spells, particularly in pots.

Soil

Any reasonable well-drained soil.

Pruning

Deadhead to prolong flowering. It is a short-lived perennial usually grown as an annual; plants that survive a mild winter are rarely as good the second year.

Feeding

A balanced liquid feed every two to three weeks in pots; in the ground usually none.

Propagation

From seed sown under cover in early spring with warmth, then planted out after the last frost.

Month by month

Months change with the climate: in southern Italy tomatoes go out two months earlier than in England.

  1. MarchSow under cover with gentle warmth. how ›
  2. MayHarden off and plant out once frost risk has passed. how ›
  3. AugustDeadhead regularly to keep flowers coming into autumn. how ›

Months based on climate: UK. Your choice stays on this device.

  1. MarchSow under cover with gentle warmth. how ›
  2. AprilHarden off and plant out once frost risk has passed. how ›
  3. AugustDeadhead regularly to keep flowers coming into autumn. how ›

Months based on climate: Northern Italy. Your choice stays on this device.

  1. FebruarySow under cover with gentle warmth. how ›
  2. AprilHarden off and plant out once frost risk has passed. how ›
  3. AugustDeadhead regularly to keep flowers coming into autumn. how ›

Months based on climate: Central Italy. Your choice stays on this device.

  1. FebruarySow under cover with gentle warmth. how ›
  2. MarchHarden off and plant out once frost risk has passed. how ›
  3. AugustDeadhead regularly to keep flowers coming into autumn. how ›

Months based on climate: Southern Italy and islands. Your choice stays on this device.

Common problems

Slugs

How to spot it. Young plants grazed after planting out.

What to do. Plant out sturdy plants and protect them at first.

Powdery mildewfull sheet ›

How to spot it. White coating on leaves late in the season.

What to do. Cosmetic at that stage; water at the base.

Weak second-year plants

How to spot it. Survivors flower poorly.

What to do. Resow each year.

Questions

Rudbeckia: is it hardy?

Perennial: H6: Hardy in the vast majority of UK gardens. It survives down to −20 °C. Gloriosa daisy: H3: Half hardy. It survives down to −5 °C.

Can it grow in a pot?

Perennial: Possible in a large pot, but happiest in the ground. Gloriosa daisy: Yes — dwarf varieties are good late-summer pot plants.

Rudbeckia: when do you prune it?

Perennial: Leave the dark seed heads standing over winter, then cut everything back to the base in early spring. In the calendar for UK, pruning falls in March. Gloriosa daisy: Deadhead to prolong flowering.

Rudbeckia: when does it flower?

Perennial: In the climate of UK it flowers in August–October. Gloriosa daisy: In the climate of UK it flowers in July–October.

When do you feed it?

Perennial: Rarely needs feeding in the ground; a compost mulch in spring is enough. Gloriosa daisy: A balanced liquid feed every two to three weeks in pots; in the ground usually none. Feeding months, UK: July–August.