The hillside behind our Austin home has a large population of escaped Hamelia patens (firebush). With record low temperatures 17°–19° F the second week of January 2010, this Mexican native exhibited crystallofolia. Unlike nearby Verbesina virginica it was not dry and dormant above ground, as can be seen in these pictures. And although not as spectacular as with V. virginica, frost formations followed roughly the same pattern, with the following exceptions, perhaps because the plants were not dormant above ground:
H. patens crystallofolia, Jan. 8–9, 2010.
Online information indicates that H. patens is sensitive to freezing (e.g., "it will freeze and die most years" answers.com [in our area]), but our plants have been in place for several years now. It remains to be seen how well they will tolerate our current record-breaking freeze of 2010.