Cartoon Bust — Head Gardener, Terrazzo Treatment, Edinburgh

Forty-one years at the same botanical garden. He arrived as an apprentice and left as the person who decided what got planted where. The garden’s trustees wanted the sculpture to be made of something that belonged to the place rather than to a foundry.

The material argument

Terrazzo is a flooring material, and it is made of leftovers: chips of marble and stone set in a binder and ground flat. It is one of the few decorative surfaces where the aggregate is genuinely visible and genuinely varied.

That suited a gardener. The chips in this piece are four colours — white, black, ochre and a sage green that matches the garden’s glasshouse frame. They are set in a pale grey ground and the surface is polished flat, so the chips are level with everything around them and read as pattern rather than as texture you can feel.

Reading as a portrait anyway

A portrait in a busy pattern is difficult. Chip patterns destroy the modelling of a face, so we took the same approach used on the pop-art bust: the form does the work and the pattern does the tone.

Where the face turns away from the light the chips get denser and darker; where the brow and the cheekbone catch light, the ground shows more. The eyes and the mouth are the only areas with no chips at all, and the effect is that the face resolves out of the pattern in exactly the place you are looking.

His hat

Every photograph of him for forty years includes the same flat cap, so the cap is in the piece and it is the one element finished in a solid colour, a dark charcoal with no chips. It frames the face and gives the sculpture a skyline.

In the garden

It stands at the entrance to the rock garden he redesigned in 1994, facing the path he walked twice a day. The trustees asked whether it would weather. It has been out for one full Edinburgh winter, which is a fair test, and the polish has held because the chips are laminate in the shell rather than a surface treatment.