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How to Grow Impatiens

Impatiens walleriana

Tender Warm Season Continuous Harvest

When to Start

Start seeds indoors 8 weeks before your last frost date. Transplant outdoors once night temperatures stay above 10°C and soil has warmed to at least 10°C.

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Growth Stages

Sow seeds
Germination ~14d
Flowering ~84d

Approximate days from start

Care Essentials

  • Feed with a balanced liquid fertilizer every two weeks once planted out. Container plants benefit from weekly feeding as nutrients leach quickly.
  • Impatiens are the go-to bedding plant for shade — one of very few annuals that flower prolifically in full shade. However, downy mildew (Plasmopara obducens) devastated traditional I. walleriana across the UK from 2011 onwards. The disease-resistant New Guinea types and Imara series are now the safer choice. They thrive in moist, humus-rich soil and are superb in containers, hanging baskets, and shady borders.

Companion Planting

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Growing Conditions

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Spacing & Planting

Plant spacing 25 cm
Row spacing null cm
Mature height 30 cm
Mature spread 30 cm

Space 20-30 cm apart depending on variety. Compact types can be planted closer. They fill in quickly and form a solid carpet of colour.

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Care Guide

Feeding
Feed with a balanced liquid fertilizer every two weeks once planted out. Container plants benefit from weekly feeding as nutrients leach quickly.
Watch for
  • Downy mildew (the devastating disease that wiped out UK busy lizzies)
  • Vine weevil in containers
  • Red spider mite in dry conditions

Pests & Diseases

Pest Vine Weevil

Identification: Irregular notches on leaf edges (adult feeding). Plants wilt and collapse despite watering (larval root damage). White C-shaped grubs in compost.

Organic treatment:
  • Apply biological nematode control (Steinernema kraussei) to containers in spring and autumn
  • Check compost for grubs when repotting
Chemical treatment:
  • Use a systemic insecticide containing acetamiprid as a compost drench
Pest Red Spider Mite

Identification: Fine webbing on leaf undersides; leaves become mottled, pale and dry; tiny mites visible with a hand lens

Organic treatment:
  • Increase humidity by misting regularly
  • Introduce the predatory mite Phytoseiulus persimilis
Chemical treatment:
  • Spray with a miticide if infestation is severe
Disease Downy Mildew Plasmopara obducens

Symptoms: Yellowing leaves, often with a subtle downy white growth on the undersides. Leaves curl downward and drop. Plants become bare-stemmed and collapse. Flowers stop forming.

Treatment: No effective treatment. Remove and destroy affected plants immediately. Do not compost — bag and bin.

Prevention: Choose resistant varieties (New Guinea hybrids, Imara, SunPatiens). Avoid overhead watering. Ensure good air circulation. Do not plant traditional I. walleriana in areas where the disease has occurred.

Disease Grey Mould (Botrytis) Botrytis cinerea

Symptoms: Fuzzy grey mould on flowers, stems and leaves, especially in cool, damp conditions. Stems may rot at the base.

Treatment: Remove affected parts promptly. Improve air circulation. Avoid overhead watering.

Prevention: Space plants well. Water at soil level. Remove dead flowers and debris regularly.

Frequently Asked Questions

How far apart should I plant Impatiens?
Plant Impatiens 25cm apart with nullcm between rows.
When does Impatiens flower?
Impatiens typically flowers approximately 35 days after transplanting.
Is Impatiens frost hardy?
Impatiens is classified as Tender.

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