Growing Impatiens: A Complete Profile

By Growing Home Greens Team · August 20, 2026

Impatiens flowers reliably in shade, which almost nothing else here does. It also carries a disease problem worth understanding before you plant a whole bed of it.

Downy mildew has no fix

NC State Extension notes that Impatiens walleriana is susceptible to downy mildew caused by Plasmopara obducens, and states plainly that fungicides used for other fungal diseases will not work on it. The disease collapsed impatiens plantings across the country and the spores persist in soil.

If a planting collapses, replanting the same species in the same place is likely to fail again. The toolbox points to Impatiens hawkeri, New Guinea impatiens, as the resistant alternative.

Deep shade is fine

Part shade to full shade, with enough moisture. It runs 6 inches to 2 feet in both directions depending on cultivar. Perennial only in zones 10 and 11, so it is an annual for nearly everyone.

Slow from seed

Ten weeks indoors before the last frost, surface sown because the seed needs light. Most gardeners buy starts instead, and given the sowing timeline that is a reasonable choice rather than a lazy one.

Source: NC State Extension Gardener Plant Toolbox, Impatiens walleriana.

Companion planting guide for Impatiens · Find your planting dates

Typically viable in USDA zones 3-11. Not sure your zone? Look it up by ZIP code.

Method: Start indoors: Start indoors from seed, then transplant outside. Impatiens needs a head start most zones can't give it by direct-sowing alone.

See exact start-indoors, direct-sow, and harvest dates for your zone →

How many Impatiens plants fit per square foot?

Spacing: 2 per square foot (square-foot-gardening spacing). Mature height: 0.5-2 ft.

Where to buy impatiens seeds

• Botanical Interests
• True Leaf Market
• Burpee
• High Mowing Organic Seeds

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See it growing

Search YouTube for "growing impatiens" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)

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Growing Impatiens: The standard answer for a shady square, and the plant a downy mildew epidemic nearly removed from gardens.

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