No-mow May... June and July! Extract from Spring/Summer edition of RSPB magazine: …Many people take part in Plantlife's 'No-mow
May', but don't take the title too literally - it'd be a problem for
wildlife if every lawn was mown on 1 June! Leave areas uncut into late summer
if you can. Do keep mowing paths through longer areas - Starlings, Blackbirds
and other wildlife also need shorter turf. If the grass grows so lush that it
flops, cut it. Otherwise, you can leave it as late as September. Ideally, cut
it over several days with shears.