Grow wild senna in full sun to light shade and moist soil that still drains. Wild senna is Senna, also sold as American senna. It is not the senna tea shrub.
Give it full sun to light shade and moist soil that still drains
| Factor | Recommended | Avoid |
|---|---|---|
| Sun | Full sun to light shade for wild senna | Do not site it in deep shade |
| Soil | Moist loam that drains after rain | Do not plant in a stagnant bog |
| Water | Keep a new clump moist through the first seasons | Do not let a new clump bake dry |
| Feed | Little or none | Do not dump nitrogen that makes floppy stems |
| Deer | American senna is usually left alone | Do not assume every Senna is deer-proof |
Wild senna wants sun and moist ground that still drains. Full sun makes more flowers. Rich, wet soil can push the stems to six or seven feet, and they may flop under the pods. Drier ground stays shorter, about three feet. Once the roots take, a dry spell is easier. [1] American senna wants that same moist meadow. Pick the kind on Types of Senna. Privet senna is a sand shrub — see How to Grow Privet Senna.
Does wild senna need full sun?
Full sun to light shade is the rule. Deep shade cuts bloom. Do not hide a meadow perennial under a dense canopy.
How often should I water wild senna?
Keep a new clump moist through the first seasons. After that, water when the soil is dry. Do not leave the crown in standing water.
Plant at the same depth as the pot, in spring or early fall
A nursery pot in spring or early fall is the usual start. Set the crown even with the surrounding soil. Space clumps about two to three feet apart so the stems can fill in. The top stays small for a year or two while the taproot fills in, so do not dig a slow clump up. Put it where it can stay. [2]
- Plant in spring or early fall, when you can water the first season. Tease circling roots if the pot is bound.
- Dig a hole as deep as the root ball and a little wider. Set the crown even with the surrounding soil.
- Backfill with the soil you dug. Water in once, then keep the first seasons from baking dry.
- Leave the clump in place. Do not try to lift and split the taproot the way you would a shallow peony.
When should I plant wild senna?
In spring or early fall, when the soil is workable and you can water. Do not plant into a frozen bed or a stagnant bog.
How far apart should I plant wild senna?
About two to three feet. Measure to the mature clump, not the small first-year top.
Cut spent stems in late winter
Cut last year's stems to the ground in late winter, before new shoots push. If you do not want a thicket of seedlings, clip ripe seed heads in late summer before the pods split. Leaving some pods feeds birds. [3]
- In late winter, cut spent stems to the ground before new shoots emerge.
- In late summer, clip ripe seed heads if you do not want seedlings. Leave a few pods if you want birds to take the seed.
- Do not shear the clump in midsummer while it is still blooming.
When do I cut wild senna back?
Cut spent stems to the ground in late winter. Clip ripe seed heads in late summer only if you do not want seedlings.
Not the senna tea shrub — and not partridge pea
The senna in tea is a different shrub, Senna alexandrina. Leaves and pods in this genus can upset a stomach, so do not brew garden wild senna as a tea. [4] Partridge pea is Chamaecrista, an annual with leaflets that fold when you touch them. Shop tags also say prairie senna. That plant is not this perennial clump.
Is wild senna the same as senna tea?
No. Wild senna is a hardy meadow perennial. Senna tea comes from a different shrub. Do not brew the garden plant.
If a new clump still looks small in year two, wait — the roots are still filling in, so do not dig it up.
FAQ
Can I grow wild senna in a pot?
A deep draining pot can hold a young plant for a season. The taproot wants open ground. Move it to the bed when you can water it in.
Can I divide wild senna?
The taproot makes a clean split hard. A nursery pot is easier than lifting an old clump. If you try a division, do it in early spring and keep the piece moist.
Why are the leaves chewed in summer?
Sulphur-butterfly caterpillars eat the leaves. The clump usually grows through it. Do not spray a host plant you wanted for those caterpillars.
How do I grow wild senna from seed?
Start from seed on Growing Wild Senna from Seed.
Related guides
Recommended plants
References
- [1] North Carolina Extension Gardener Plant Toolbox -
https://plants.ces.ncsu.edu/plants/senna-hebecarpa/ - [2] USDA NRCS Plant Materials -
https://plants.sc.egov.usda.gov/DocumentLibrary/factsheet/pdf/fs_sehe3.pdf - [3] Plotwright -
https://plotwright.com/plants/senna-hebecarpa - [4] Lady Bird Johnson Wildflower Center -
https://www.wildflower.org/plants/result.php?id_plant=sehe3
This note is part of Senna Guides.
More first-season notes by plant are gathered in How to Grow Guides.
Updated: Reviewed by Bosquelle Editors