How to Grow Impatiens
Impatiens walleriana
Impatiens are the ultimate shade-loving bedding plant, flowering non-stop from planting until the first frost. Sow seed indoors in warmth from February to March — they need light to germinate, so do not cover. Plant out after all frost risk has passed into moist, humus-rich soil in shade or partial shade. The critical issue for UK growers is downy mildew, which devastated traditional busy lizzies from 2011. Choose resistant varieties (New Guinea hybrids, Imara, or SunPatiens series) for reliable results. They are self-cleaning and need minimal care beyond regular watering and fortnightly feeding.
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
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.
Growing Conditions
Pet Safety
- Sow indoors
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- Transplant out
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- First harvest
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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.
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.
- Apply biological nematode control (Steinernema kraussei) to containers in spring and autumn
- Check compost for grubs when repotting
- 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
- Increase humidity by misting regularly
- Introduce the predatory mite Phytoseiulus persimilis
- 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.
