Marcus graduated with Distinction from the Inchbald School of Garden Design, after a radical change of career. In 1991 he was commissioned from RMA Sandhurst into the Scots Guards, and served on overseas operations as an Army officer for 7 years, including three years as a Royal Equerry. While at the Inchbald, he teamed up with a fellow student to create his first garden at the Chelsea Flower Show, which went on to win a Gold Medal and Best Show Garden in its category. He has made four further gardens at Chelsea, most recently winning his third Gold Medal for the Telegraph Garden in 2015.