Glad you enjoyed the article, Tee and Lin. I appreciate your kind comments.
The Lespedeza species that is a weedy offender is actually Lespedeza capitata:
I don't think that Lespedeza thunbergii is at all weedy, but I could be wrong. It doesn't get a chance to be a pest here, because in our zone 5 garden, the season is not long enough for the plant to produce seed. It just produces a clump that gradually gets larger each year. It would be interesting to hear from gardeners who have grown it in warmer zones.
Tee, if your Lespedeza is thunbergii and you decide to grow it , please let me know the result. Thanks!