Urk! What does this mean? On Monday night I saw it on the back of some plant food meant for acid-loving plants such as azalias, orchids and gardenias (which I love), and ericacious plants.
So if you get it wrong, you're in trouble.
The first clue was that the list of plants included
heather. The second: when I looked up the word, it referred me to ericaceous.
Now that's a bit like erica and herbaceous.
So it refers to the genus ericaceae - which is, in fact, a family that includes heathers, and
grows in harsh and acidic environments.
Although I would expect the two spellings to be used interchangeably, anecdotally it looks like the spelling ericaceous is used in a strict botanical sense, while ericacious seems to be used mostly in a gardening context.
Anyway, it looks like I'll restrict this plant food to the gardenia and the orchids...