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Dahlia

Dahlia pinnata

Flower

Dahlias are tuberous perennials grown as annuals in cold climates, producing an extraordinary range of flower forms and colours from midsummer until first frost. Single and semi-double varieties are most valuable for attracting pollinators.

Growing Conditions

Sunlight

Full Sun

Water Needs

Moderate

Soil

Rich, well-draining loam; pH 6.5–7.0

Spacing

12–36 inches depending on variety

Days to Maturity

90–120 days from tuber planting to full flower

Growing Zones

1
2
3
4
5
6
7
8
9
10
11
12
13

Thrives in USDA Zones 8–11

Companion Planting

Good Companions

Keep Away From

No known antagonists

When to Plant

  • Transplant

    Plant tubers after last frost, 4–6 inches deep

  • Harvest

    Dig tubers after first frost in cool climates; store in frost-free conditions

Organic Growing Tips

  • Choose single-flowered varieties for best pollinator value; pompom types have limited nectar accessibility.

  • Pinch out the central growing tip when the plant has 3–4 sets of leaves for bushier, more floriferous plants.

  • Dig and store tubers in barely damp compost in a frost-free shed in climates with freezing winters.

  • Apply a thick straw mulch over tubers left in the ground in borderline zones for winter protection.

Common Pests

  • Aphids
  • Slugs
  • Earwigs
  • Powdery Mildew
  • Vine Weevil

All pest management in Garden uses safe, organic, non-toxic methods only. No synthetic pesticides, ever.