Puma Investments and individual investors have financed the creation of the new business.
Puma Investments is the principle investor in Rosebourne, which opened its first garden centre in Andover 18 months ago and is developing a further site in Aldermaston set to open later this year.
Somerton has signed a franchise agreement with Rosebourne and will trade at its centres under the Rosebourne brand.
Paris is Somerton's chief executive. She was previously at the £45m turnover Garden & Leisure Group as operations and buying director between before it was sold to Wyevale Garden Centres.
Paris worked with Rosebourne's Neville Prest at Garden & Leisure. The other director listed for Chichester-based Somerton is Paul Silva. Paris was at Edinburgh Woollen Mill and Harrods before entering the garden industry.
Rupert West, investment director at Puma and Head of Puma EIS, said: "We are delighted to be backing Somerton Ltd and to have such an experienced retailer at the helm in Carol Paris.
"There is proven demand in the market for the kind of high quality offer that Somerton will be providing and the company is now well funded for site acquisition and development."
Puma Investments is a fund management business with offices in London, Liverpool and Edinburgh. It provides growth capital of £1million to £10million to UK SMEs across all sectors.