Ask Mr. Smarty Plants

There doesn't seem to be any readily available information on the germination of the seeds of Sophora gypsophila (Guadalupe Mountain necklacepod) specifically, but there are a couple of sources of information about Sophora in general.

Jill Nokes in How to Grow Native Plants of Texas and the Southwest says:

"Germination of Sophora is delayed by a hard seed coat. Seeds may be filed or mechanically scarified with a knife. Or soak them in concentrated sulfuric acid for 30-90 minutes immediately before sowing.

Pretreated seeds will germinate within 2 weeks in a greenhouse or outdoors after the soil has warmed. Plant the seeds in individual containers that are deep enough to accommodate a relatively long initial root. The soil medium should be extremely well drained and drenched with a fungicide before the seeds are sown. Seedlings do not transplant well from the flat and are also sensitive to overhead watering."

Specifically about S. gypsophila she says:

"Though slow growing and susceptible to damping off, this species would make a handsome ornamental hedge or border plant... Guadalupe Mountain Laurel will not thrive in areas with higher humidity and high nighttime summer temperatures. It is also intolerant of poor drainage."

From the Thompson & Morgan Successful Seed Raising Guide the entry for Sophora gives the time for germination as 10-21 days at a temperature of 70-85 F. The growth medium should be well drained and the seeds should just be covered with compost or sharp sand. Chipping and soaking the seeds before sowing is recommended. Their instructions for chipping and soaking read:

"SPECIAL TREATMENT - Hard Seeds-Chipping

Some seeds, e.g. Sweet peas, lpomaea etc., have hard seed coats which prevent moisture being absorbed by the seed. All that is needed is for the outer surface to be scratched or abraided to allow water to pass through. This can be achieved by chipping the seed with a sharp knife at a part furthest away from the 'eye', by rubbing lightly with sandpaper or with very small seed pricking carefully once with a needle etc.

SPECIAL TREATMENT - Hard Seeds-Soaking

Soaking is beneficial in two ways; it can soften a hard seed coat and also leach out any chemical inhibitors in the seed which may prevent germination. 24 hours in water which starts off hand hot is usually sufficient. If soaking for longer the water should be changed daily. Seeds of some species (e.g. Cytisus, Caragana, Clianthus) swell up when they are soaked. If some seeds of a batch do swell within 24 hours they should be planted immediately and the remainder pricked gently with a pin and returned to soak. As each seed swells it should be removed and sown before it has time to dry out."

Mr. Smarty Plants hopes this information helps you achieve successful germination of your Guadalupe Mountain Laurel seeds!