The garden showed 50 different yellow plants and looked at the role of pigments, in particular carotenoids and flavanoids, which give yellow plants their colour.
Jane Brook was co-designer and Joseph Rochford Nurseries, Provender Nurseries, Primrose Hall and Cayeux Irises were among suppliers. Peter Seabrook also supplied a yellow acer.
Julie Dowbiggin said: "We're thrilled. Because the college is 50 years old, we decided to look at yellow plants and pigments in the plant kingdom. The college has not won gold for eight or nine years so to get it on our 50th is amazing."
The plants will be used to create a garden at the London college helped by Garden Media Guild and Paul Rochford.
Colour in plants is created by plant pigments. They exist in a wide variety of forms and are found in flowers, leaves fruit and vegetables. Pigments selectively absorb and reflect light of specific wavelengths and it is the reflected light that we see as the flower or leaf colour. Pigments have important roles in photosynthesis, in pollination and in protection of plant tissues.
Unlike in leaves, yellow flower colour in petals is due to many hundreds of plant pigments which vary from species to species. Some are carotenoids e.g. carotene, xanthophyll and lutein. Others are flavonoids such as chalcones and aurones which are deep yellow and flavones, flavonols and flavanones which are light yellow or nearly colourless. In a study of Narcissus flowers, 10 carotenoids and 18 flavanoid compounds were found in 15 different cultivars.
Meanwhile, Sparsholt College also won gold for its Chelsea exhibit. The Help for Heroes The Force for Good Garden won a gold and Best Discovery Exhibit at RHS Chelsea Flower Show 2018.