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Fabaceae FAMILY

Thermopsis macrophylla

Thermopsis macrophylla

Edibility
0/5
Medicinal
2/5

Safety & Hazards

None known

Cultivation Details

HabitPerennial
Growth—

Thermopsis macrophylla is a moderately cold-hardy plant, able to tolerate temperatures down to around -15°c when fully dormant. It grows best in areas with hot summers. Requires a sunny position, succeeding in any moderately fertile, well-drained soil[1]. Plants can spread fairly rapidly by means of rhizomes, and can out-compete less vigorous plants[1]. This species has a symbiotic relationship with certain soil bacteria; these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[2].

Propagation

Pre-soak the seed for 24 hours in warm water and then sow in early spring in a cold frame. Germination is usually good and within a month[PFAF]. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts. Division in spring. Divided plants do not establish readily[3]. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-21. <temperate.theferns.info/plant/Thermopsis+macrophylla>

Pollinators

Insects

References

  1. [1]The New RHS Dictionary of Gardening. 1992. — Huxley. A. · MacMillan Press · 1992 · ISBN 0-333-47494-5 ↩︎Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
  2. [2]Nodulation Plants in GRIN Taxonomy — United States Department of Agriculture · http://www.ars-grin.gov/~sbmljw/cgi-bin/taxnodul.pl?language=en ↩︎An online database listing plants that have either positive or negative reports on root and stem nodulation with nitrogen-fixing bacteria.
  3. [3]RHS Dictionary of Plants plus Supplement. 1956 — F. Chittendon. · Oxford University Press · 1951 · ISBN - ↩︎Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaced in 1992 by a new dictionary (see [ 200 ]).
  4. [4]Annals of the Missouri Botanical Garden Vol. 81 — Missouri Botanical Garden; St. Louis. · 1994 · http://www.biodiversitylibrary.org/ · ISBN 0026-6493 ↩︎A botanical journal with various articles, including a revision of the genus Petrea. It can be downloaded from the Internet.
  5. [5]Native American Ethnobotany — Moerman. D. · Timber Press. Oregon. · 1998 · ISBN 0-88192-453-9 ↩︎Very comprehensive but terse guide to the native uses of plants. Excellent bibliography, fully referenced to each plant, giving a pathway to further information. Not for the casual reader.
  6. [PFAF]Plants for a Future — pfaf.org ↩︎