Just south of the Austford site in Streetfield Wood is a large clump of the introduced broad-leaved bamboo (Sasa palmata) growing happily among the Scot's pines.
This arrived in Britain in 1889 and was one of the earliest bamboo introductions so it is not surprising to see it flourishing in what must once have been part of the Austford garden.
It is native to Japan where it is a widespread species called 'chimaki zasa' and various other names.
'Chimaki' are savoury rice dumplings wrapped in leaves of this bamboo then steamed or boiled (something I think I might have a go at now I know where to get the leaves).
In parts of North America and some other places this bamboo has become an aggressive alien, but it seems to be reasonably well-behaved in Britain simply forming a larger and larger clump from the original planting.