Herman Miller, On 15/11/2012 02:11:
> On 11/14/2012 3:22 AM, R A Brown wrote:
>> I know of no uses of "to blow" with a passive meaning, i.e. "are
>> being blown."
> "The answer, my friend, is blowing in the wind..." comes to mind.

Indeed. If you have access to the OED, it's _blow_ v.1 sense 12b. The earliest citations are:

1842   Tennyson Goose xiii, in Poems (new ed.) I. 233   Her cap blew off, her gown blew up.

1842   Tennyson Day-dream in Poems (new ed.) II. 156   The hedge broke in, the banner blew.

The version of _In Flanders Field_ I'd known has _grow_ at the end of the first line, but on first reading the version with _blow_ (in this thread), I had an image of the poppies fluttering gently in the breeze, like banners or pennants.