Located in southern England, Hertfordshire is one of the home counties, immediately north of London. Its boundaries approximately follow the drainage divides of the River Lea and the Colne. The land is mainly agricultural and rural in the eastern regions, and much of it is protected by greenbelt, including the Chiltern Hills Area of Outstanding Natural Beauty. The highest point in Hertfordshire is 803 feet (245 m) above sea level, this is a quarter mile (400 m) from Hastoe within Pavis Wood.
The geological formations in Hertfordshire belong to what is known as the London Basin, formed when tectonic plates compressed to create sedimentary rock, composing of sand and gravel, which has been quarried in the past. Prehistoric glacial activity in the region led to the formation of much chalk and clay. Chalk rivers in the are used to be a good source of water-cress, whilst the clay was historically used for local brick-making. Today, chalk is still utilised to extract groundwater for the region’s water supply.
The climate in Hertfordshire is temperate, with average temperatures between 6-14°C. The summertime can however reach highs of 22°C, and this period sees the least rainfall. Sunshine hours average around 200 hours per month between May and August, making propagation an ease for gardens in Hertfordshire.