Plant name | Zone | Start seeds indoors (spring/fall) | Start seeds outdoors (spring/fall) | Plant seedlings/transplants outdoors (spring/fall) | Plant spacing | # plants per person |
Astilbe | 3a | Not recommended | Not recommended | On/around May 15 (after last frost); July 15-Aug. 1 | 6-24 inches (depending on variety) | n/a |
Astilbe | 3b | Not recommended | Not recommended | On/around May 15 (after last frost); July 15-Aug. 1 | 6-24 inches (depending on variety) | n/a |
Astilbe | 4a | Not recommended | Not recommended | On/around May 15 (after last frost); July 15-Aug. 1 | 6-24 inches (depending on variety) | n/a |
Astilbe | 4b | Not recommended | Not recommended | On/around May 15 (after last frost); July 15-Aug. 1 | 6-24 inches (depending on variety) | n/a |
Astilbe | 5a | Not recommended | Not recommended | On/around April 15 (after last frost); Aug. 15-Sept. 1 | 6-24 inches (depending on variety) | n/a |
Astilbe | 5b | Not recommended | Not recommended | On/around April 15 (after last frost); Aug. 15-Sept. 1 | 6-24 inches (depending on variety) | n/a |
Astilbe | 6a | Not recommended | Not recommended | On/around April 15 (after last frost); Aug. 15-Sept. 1 | 6-24 inches (depending on variety) | n/a |
Astilbe | 6b | Not recommended | Not recommended | On/around April 15 (after last frost); Aug. 15-Sept. 1 | 6-24 inches (depending on variety) | n/a |
Astilbe | 7a | Not recommended | Not recommended | On/around April 15 (after last frost); Aug. 15-Sept. 1 | 6-24 inches (depending on variety) | n/a |
Astilbe | 7b | Not recommended | Not recommended | On/around April 15 (after last frost); Aug. 15-Sept. 1 | 6-24 inches (depending on variety) | n/a |
Astilbe | 8a | Not recommended | Not recommended | Oct. 15-March 30 | 6-24 inches (depending on variety) | n/a |
Astilbe | 8b | Not recommended | Not recommended | Oct. 15-March 30 | 6-24 inches (depending on variety) | n/a |
Astilbe | 9a | Not recommended | Not recommended | Oct. 15-March 1 | 6-24 inches (depending on variety) | n/a |
Astilbe | 9b | Not recommended | Not recommended | Oct. 15-March 1 | 6-24 inches (depending on variety) | n/a |
Astilbe | 10a | Not recommended | Not recommended | Nov. 1-March 30 | 6-24 inches (depending on variety) | n/a |
Astilbe | 10b | Not recommended | Not recommended | Nov. 1-March 30 | 6-24 inches (depending on variety) | n/a |
Astilbe | 11a | Not recommended | Not recommended | Nov. 1-March 30 | 6-24 inches (depending on variety) | n/a |
Astilbe | 11b | Not recommended | Not recommended | Nov. 1-March 30 | 6-24 inches (depending on variety) | n/a |
* Grows as a perennial in Zones 3-9; plant as a cool-season annual in warm climates. Plant outside in the spring after the last frost, or 6-8 weeks before the first frost in the fall.