Lespedeza Seed Germination

In the catalogue it says that for lespedeza germination,"special treatment required" I assume that means some kind of cold treatment; i.e. "stratification". Do you know what the specific treatment is?

This genus of plants has impermeable seed coats. To speed up water absorption it is recommended that the seed coat be punctured with a tool such as a needle or nicked with a knife. Try to only go through the seed coat, not go into the seed. Make sure you do such nicking well away from the seed scar of the seed, because the embryo is located very close to it. An injury to the embryo tends to be fatal to the seed.