as a general rule of thumb you should do this at the end of autumn or the early spring so you dont stress the said trees/shrubs etc as much as theres know sap moving and the ground isnt realy cold or frozen . weather its moving or cutting branches of . i prefer planting very early springmyself .

'Stocks' are annuals they only flower the once and then die off. Remove completely around now.

...unless it is the perennial white flowered Stock, Matthiola incana! This gets leggy after a couple of years and needs re growing from seed.