Golden bamboo by a Kentucky freeway

Roaring back to the Louisville airport after the AHS Garden School, a flash of gold caught my eye by the roadside. The cab booked by the hotel had not arrived (thank you YellowCab of Louisville) so one of the hotel staff drove me to the airport – he spoke little English and had never been to the airport before! So when I spotted a grove of golden stems by the side of the freeway, trying to make him understand that I wanted him to stop to take a look didn’t seem an option – and, anyway, by then I was late for my plane.

When I got home I checked on the USDA Plants Database which gives distribution maps for both native and non-native plants and it looks as if the familiar Golden Bamboo, Phyllostachys aurea, grows nowhere in KY or nearby while the Yellow Grove Bamboo, P. aureosulcata, grows in a couple of KY counties, but not near Jefferson County, where I saw it alongside I-71. What's more, only the ‘Aureocaulis’ form of P. aureosulcata has stems which are completely yellow, and they are more a yellow color than the golden orange of P. aurea. Perhaps it was P. aureosulcata ‘Aureocaulis’? I’m not sure.

So… is this a new sighting? Whichever species it was there was quite a lot of it but flashing by in a rush to the airport with trucks spoiling the view it was impossible to be sure what it was. Any thoughts, anyone?