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.
Rhosgoch
Rhosgoch is a tiny town in the north of the island of Anglesey, Wales, concerning 3.5 miles (5.6 km) to the south-west of Amlwch. A brief range to the west of the town is the small lake Llyn Hafodol and a mile to the south is Anglesey's largest body of water the tank Llyn Alaw (Water Lily Lake). The town when had a station on the Anglesey Central Railway. Although the tracks still exist, no train has actually operated on them given that 1993. Also attached to the railway, was a brief south-west dealing with spur that caused an oil terminal. This was linked to a drifting dock in the sea off of Amlwch, where super-tankers might dock in all tides as well as feed oil using Rhosgoch and a pipe to Stanlow oil refinery. This procedure lasted for 16 years between 1974 and also 1990. The first twister of the record-breaking 1981 United Kingdom tornado episode, an F1/T2 tornado, touched down close to Rhosgoch at around 10:19 local time on 23 November 1981.