Astragalus
Deep, sunny, patient.
- A deep, stone-free bed in full sun.
- Three or four years before the root is lifted.
- Winter drainage matters more than the zone label.
- No trellis or root barrier, but no wet clay either.
Which root herb should you grow?
Astragalus, codonopsis and licorice compared by site, time and failure risk — not by medicinal claims.
Three roots, three different gardens.
The table compares the growing decision only. Safety flags are a prompt to read the profile and speak to a clinician, not a ranking.
| Decision | Astragalus | Codonopsis | Licorice |
|---|---|---|---|
| Habit | Clump with taproot | Twining vine | Spreading rhizomes |
| Hardiness | 5–9 | 5–9 | 4–9* |
| Light | Full sun | Sun to part shade | Full sun |
| Water | Low–medium | Medium | Low–medium* |
| Soil | Deep, sandy, neutral–alkaline | Well-drained loam | Deep, well-drained, neutral–alkaline |
| Support / containment | None | Trellis | Root barrier |
| Years to harvest | 3–4 | 2–3 | 3–4 |
| Main failure mode | Wet crown in winter | Root disturbance; dry soil | Wet crown; spreading rhizomes |
| Safety flag | Autoimmune, immunosuppressant, pregnancy | Limited safety data | Blood pressure, potassium, pregnancy |
| Best for | Deep sunny bed, patient grower | Part shade with vertical space | Dedicated dry bed with containment |
* Licorice hardiness and moisture vary by source: PFAF lists 5–9 and moist soil, while many garden guides describe it as drought-tolerant once established. Treat the table as a starting point, not a cultivar-level guarantee.
The test that matters
Zone labels don't measure drainage.
Astragalus comes from dry, sunny ground; licorice tolerates a wider range of soils but still needs winter water to drain away. A zone 5 garden can grow either in one bed and lose it in another, because winter water is the deciding variable. The RHS describes the mechanism: saturated soil reduces oxygen to the roots and can cause yellowing, root rot and death (RHS).
Before planting, dig a hole in the intended bed, fill it with water, and watch how long it stands after rain. If the bed is a low corner or the soil stays slick for days, raise it. Compost improves structure; a mound lifts the crown; mulch should stop short of the stem. Do not work wet clay.
- Water still standing after a day? Treat drainage as a problem.
- Low corner or downslope path? Raise the bed or plant elsewhere.
- Clay that shines when wet? Wait for it to dry; do not dig it wet.
- Mulch touching the crown? Pull it back before winter.
Choose by the garden you actually have.
Codonopsis
Part shade with vertical space.
- A trellis, fence or obelisk for a twining vine.
- Two or three years to a usable root.
- Consistent moisture without a soggy crown.
- Avoid disturbing the taproot after planting.
Licorice
Dedicated dry bed with containment.
- Full sun and a bed of its own, or a root barrier.
- Three or four years to a useful root.
- Do not let winter water sit over the crown.
- Read the blood-pressure and potassium cautions first.
What this comparison does not tell you.
- No yield ranking. Root weight depends on soil depth, climate, age and cultivar; we have not run side-by-side yield trials.
- No medicinal ranking. Safety flags are cautions, not recommendations to use any root.
- No cultivar-level guarantee. Hardiness and moisture ranges vary by source and provenance.
- No substitute for your own site test. Drainage, winter rain and summer heat decide more than a table can.
Sources
- Plants for a Future — Astragalus membranaceusPFAF
- Plants for a Future — Codonopsis pilosulaPFAF
- Plants for a Future — Glycyrrhiza uralensisPFAF
- NCCIH — Astragalus: Usefulness and SafetyNCCIH
- NCCIH — Licorice Root: Usefulness and SafetyNCCIH
- RHS — Waterlogging and flooding solutionsRHS
Accessed for horticultural and safety context. The comparison is an editorial synthesis of these sources, not a controlled trial. Compiled and edited by the Herb Ledger editorial team. See the editorial policy.