Corruption of ACHE sb.2, as in Sweet Ash: Hare’s Parsley (Anthriscus sylvestris); and † Ash of Jerusalem (obs.): prob. Dyer’s Woad (Isatis tinctoria).

1

1548.  Turner, Names of Herbs, 40. Wyld wad is called in Englishe ashe of Hierusalem.

2