This is is a plant with an established plant just potted up for your convenience.
Contorted willow or twisted willow is an easy-to-grow hardy deciduous tree. It is grown for its interesting twisted branches which are brightly coloured (yellow-green or reddish orange) in winter. You can let it grow into a small tree, or cut it back hard every spring (pollarding, coppicing or stooling) to encourage even more vigorous young branches.
It is a tree, so it will be big, but not massive like an ordinary weeping willow.
It doesn't really flower, but it seems to attract its fair share of wildlife.
It seems to be pretty unfussy when it comes to soil conditions and sun, but it's good to grow it somewhere the low winter sun will light up its branches. Unfortunately I couldn't find a photo of that, but you can google.