I know that the kanji 英 now really has the exclusive meaning of "English", such as in 英語, but I'm wondering what the original meaning was. It's used in words like 英雄, which obviously don't have anything to do with being English. Is it just phonetic when used in words like that, or did it actually have an older meaning?
My dictionary 漢字源 lists as meanings
The literal meaning being related to a flower, the extended meaning being "lovely" or "outstanding" or "someone skillful". The words 英雄 "hero" and 英明 "intelligent" are listed under this extended meaning.
Henshall writes on p.130 of A Guide to Remembering Japanese Characters:
It's not true that 英 "now really has the exclusive meaning of English", but it's acquired that meaning as well. It's still used in its usual senses of "superior, talented, brave" in compounds like 英雄, 英明, or 英知.
In reference to England, it seems that 英 is an abbreviation for the ateji 英吉利.
The dictionary 精選版 日本国語大辞典 says:
And the character dictionary 新漢語林 says:
Wikipedia backs this up:
So I think that, in reference to England, it was used for its sound in Chinese rather than for its meaning, and that's why we find two unrelated sets of meaning ("English" and "superior").
I think the literal meaning of "flower" is uncommon in Japanese, although you'll find it used to write certain flower names such as 蒲公英(たんぽぽ).