British artist Dan Harvey and Heather Ackroyd are the creative minds behind these large scale living grass illustrations. Their inventive process involves mounting large plots of seedling grass onto a wall and projecting an image upon it. The varying degrees of light which the grass is exposed to cause it to grow in varying shades of yellow and green.
The use of grass as a medium to capture an image began as an accidental discovery. After having left a ladder leaning over a grass wall they found that its image had been imprinted. From there they began experimenting with the capabilities of grass to capture simple designs and then later working up to more complex images. Along the way they have collaborated with scientist at the Institute of Grassland and Environmental Research in Wales in the use of a stay-green grass which allows them to preserve the image for longer periods of time.
As time goes by...
http://www.ackroydandharvey.com/downloads/Passing-Presence-AckroydAndHarvey.pdf