You should pull up and remove weeds by hand as and when they appear. If it is a regular problem, you might need to reseal the paving. In extreme cases, the sub layer itself may need to be re-laid. You can use weed killer, however some paving can be discoloured by stronger weed killers.
Yarm
Yarm is a town in North Yorkshire, England. The town is on the south bank of the River Tees as well as is traditionally part of the North Riding of Yorkshire. The bridge at Yarm marked the outermost reach of tidal circulation up the River Tees up until the opening, in 1995, of the Tees Battery, which now manages river circulation above Stockton. As the last bridge on the river prior to the sea, it was superseded by a brand-new toll bridge opened up in Stockton in 1771. The earliest part of the town, around the High Street, is positioned in a loophole of the river, and the newer parts of the town include the factor where the River Leven meets the River Tees. The community is regulated as part of the District of Stockton-on-Tees.