Yellow Flower Bud Thorn Bush

This thorny flower bush is widespread in some parts of the UK. I don't know what it's called but it's an excellent bush for decorative and security purposes. No ones jumping over your fence with these on the other side, not without getting into a scuffle with some thorns. They are Sharp! I'm not mad into bushes and flowers or anything but I took some seeds from this bush once, took them home and planted them. This was about 2 years ago, and now two years later it's still alive doing well, but it's remained very small. This bush is very tough and hardy but a very slow grower.