Founder Chris Bonnett said: "Over half of our traffic now comes from mobile devices so it is highly important to serve these visitors in the most efficient way possible, and our old site simply wasn’t up to the job."
The bounce rate has dropped "significantly" since launch, he added.
Bonnett said: "We want to be the first port of call for anyone looking to buy plants for their garden that would normally initially turn to a bricks and mortar garden centre or nursery. The depth of range and quality aspect should serve the company well against other firms that traditionally focus on the plug plant market. Our 2015 turnover was comfortably in excess of £5m, but we feel the online plant and garden market is only just getting started, and there is no reason our business cannot grow to match the likes of Primrose which specialises in the dry goods side of things - that would certainly be our aim long term. Naturally any new website takes time to bed in, but continual improvements are on the agenda."