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.
Lostwithiel
Lostwithiel is a civil parish and also small town in Cornwall, England, United Kingdom ahead of the tidewater of the River Fowey. According to the 2001 census it had a population of 2,739, boosting to 2,899 at the 2011 census. The Lostwithiel selecting ward had a population of 4,639 at the 2011 census. The name Lostwithiel comes from the Cornish "lostwydhyel" which indicates "tail of a woody location". The town is situated in the Fowey river valley, positioned in between the A390 road from Tavistock to Truro and also the top tidal reaches of the river. Lostwithiel train station is on the Cornish Main Line from Plymouth to Penzance. It is located on the south side of the community, just throughout the medieval bridge. The line was originally developed for the Cornwall Railway which developed its main workshops here, however the surviving workshop structures were transformed into apartments in 2004. A branch line takes china clay trains to Fowey. The town includes the residential areas of Bridgend to the eastern as well as Rosehill as well as Victoria to the west of the River Fowey.