槑 is a variant character of 梅 comprised of two 呆. Both are pronounced "méi", and mean "plum blossom" (Prunus mume). But what would the glyph origin be like? 呆, pronounced "dāi" and meaning "stupid", lends neither phonetic nor semantic semblance to 槑.
My guess is that it's a pictogram of two plum bushes standing in a row next to each other. But I could also see it arising from a graphical corruption of 梅: the "hat" of the right 每 portion "sliding off" on top of the left 木 portion and morphing into 口, and the 母 alone on the right without a "hat" corrupting into another 呆.
I can't seem to find any coverage of it, at least online, so I'm asking here. (Maybe also add the correct glyph origin to the Wiktionary page of 槑 once figured out?)