Communial alley upkeep

Hi, im after some sage like advice. After living in my terrace for the past 14 months, i decided to clear the rear alley way. This is a communial path providing rear access to four houses. As this is communial, its up to the residents to maintain, not the council , however im the only resident who wants to use the alley. I wanted to gain access to the rear of my property for a new shed and bike access etc...
The alley's about 20 meters long by 1.5 wide. The floor is topsoil over some hardcore. The alley was heavly overgrown with brambles and flipping Japenese Knotweed. Have hacked and slashed the triffids backand dug up the roots of the Knotweed 'some hope'. I would like advice on how to best keep the weeds to a minimum, as i dont fancy fighting my way through every couple of months. All advice gratfully received thanx LG.