Growing black-eyed susan in zone 3b
(Zone 3b = an average winter low of -35°F to -30°F.)
In USDA zone 3b, the typical last spring frost is May 17 and the first fall frost is September 23. Here is when to plant black-eyed susan against those dates.
Typical timing
Zone 3b planting schedule
Evidence trail
How these dates are built
Sprout applies the cited planting offsets to the typical zone 3b frost anchors. The result is a planning baseline for the zone, not a local weather forecast.
- USDA Plant Hardiness Zone Map, 2023USDA Agricultural Research Service / Oregon State University PRISM Group. Supports the USDA hardiness-zone band.
- U.S. Climate Normals 1991-2020NOAA National Centers for Environmental Information. Supports the median spring and fall freeze dates.
- 'Prairie Sun' Black-eyed Susan, Rudbeckia hirtaUniversity of Wisconsin-Madison Division of Extension (Wisconsin Horticulture). Supports outdoor transplant timing (normalized).
Method note
Lifecycle (commonly a reseeding annual or short-lived perennial; sometimes listed perennial to zone 3a, recorded as annual), transplant after all risk of frost is past (start-only anchor expressed as weeks 0-2), spacing at least 1 ft (up to 2 ft in warmer/longer-season areas), full sun, barely cover seed (light encourages germination; sprouts in 10 to 21 days), problems (powdery mildew helped by spacing for air circulation, rabbits, slugs on young plants, self-seeding if not deadheaded; not favored by deer). Seed is surface-sown (light-dependent), so plantingDepthInches is omitted. No pH range or per-week water rate given; zoneRange omitted (only a lower zone is stated).
These are zone 3b averages
Computed from 224 ZIP codes in zone 3b. Your town's frost dates vary; enter your ZIP for dates built on your nearest weather station.
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Put these dates to work
The plant profile covers spacing, light, water, soil, and source-backed timing details.