Eartha rhymes with:
bertha, hertha, murtha, tregurtha, agatha, aletha, anantha, aretha, atha, bartha, bertha, bolitho, botha, calantha, cleantha, cliantha, diantha, hertha, hiawatha, hyacintha, iantha, inkatha, jacintha, juditha, katha, letha, martha, mccartha, mintha, murtha, naphtha, philantha, ramtha, samantha, tabitha, tregurtha
Eartha sounds like:
eared, earhart, earth, earthy, earwood, ehret, ehrhard, ehrhardt, ehrhart, erda, erhard, erhardt, erhart, erode, eroded, erred, errett, erte, ertha, erudite, ewart, ewert