Nick the hard wild senna seed, soak it, and sow it about an eighth of an inch deep.
Nick the hard seed coat, then soak it
| Factor | Recommended | Avoid |
|---|---|---|
| Coat | Nick or sand the hard coat, then soak in warm water | Sowing a hard, unswollen seed |
| Cold | Optional. A fall sowing outdoors can overwinter on its own | Treating a fridge stretch as the only way |
| Depth | About an eighth of an inch | Burying the seed an inch down |
| When | Spring after frost, or fall | Sowing into frozen ground |
Wild senna seed has a hard coat, so water cannot get in until you nick it. Rub the seed on sandpaper, or chip a corner, then soak it in warm water for a few hours. The seed should swell. Discard seeds that stay hard. Cold storage is not required. [1] A light sanding and a fall sowing outdoors also work. Set the packet outside when nights stay cold, or use a short fridge stretch. That fridge step is optional, not the rule. [2] American senna uses that same nick. Germination is often patchy even after a nick, so sow more seed than clumps you want.
Do I have to chill wild senna seed?
No. Nick the coat and sow. A fall sowing outdoors can overwinter on its own. A fridge stretch is optional, not the rule.
Sow about an eighth of an inch deep
Sow about an eighth of an inch deep, in spring after frost or in fall. Cover the seed about as deep as it is tall. Keep the surface from drying until seedlings show, but do not leave the mix soggy. Germination can be slow and patchy. [3] Early-fall sowing is a usual start. A spring sowing still needs the nick first. [4] A nursery clump you already own uses How to Grow Wild Senna.
- Nick or sand the coat, then soak the seed in warm water for a few hours.
- Sow about an eighth of an inch deep, in spring after frost or in fall.
- Keep the surface from drying until seedlings show. Do not keep the pot soggy.
- Move a seedling on before the taproot hits the bottom of a small pot.
How deep do I sow wild senna seed?
About an eighth of an inch. Cover it about as deep as the seed is tall. Do not bury it an inch down.
If the seed stays hard after a soak, nick it again and soak once more — do not bury a hard seed.
FAQ
Can I sow privet senna this way?
Privet senna is the evergreen sand shrub. Site that plant on How to Grow Privet Senna. The nick still helps if you already have that seed.
Can I collect pods from the garden?
Yes. Wait until the pods are brown and dry. American senna opens its pods and drops seed. Maryland senna keeps them closed later.
Do I need a pea inoculant?
No. An inoculant can help, but it is not required. Nick the coat first.
Related guides
Recommended plants
References
- [1] USDA NRCS Plant Materials -
https://plants.sc.egov.usda.gov/DocumentLibrary/factsheet/pdf/fs_sehe3.pdf - [2] Jenkins Arboretum & Gardens -
https://www.jenkinsarboretum.org/wild-senna/ - [3] Friends of the Eloise Butler Wildflower Garden -
https://friendsofeloisebutler.org/pages/plants/wildsenna.html - [4] North Carolina Extension Gardener Plant Toolbox -
https://plants.ces.ncsu.edu/plants/senna-hebecarpa/
This note is part of Senna Guides.
More notes on making another plant live in Propagating Guides.
Updated: Reviewed by Bosquelle Editors