This paper describes a new robot specifically developed for topiary trimming and evaluatesits performance through a novel evaluation method. Experiments were carried out in a realgarden letting the robot trim spherical-, cylindrical- and cuboid-shaped boxwood topiaries.The robot's performance was evaluated using a quantitative evaluation method, whichmade accurate 3D point clouds of the bush before and after trimming using photogram-metry. For each point in these point clouds, the Euclidean distance to the ground-truthshape was calculated and classified as correctly trimmed (CT) when the distance waswithin 2 cm of the ground-truth shape. Using this information the percentage of CT pointsbefore and after trimming were compared. Results show a reasonable robot accuracy whentrimming spherical topiaries, reporting a 24 percentage point increase of CT points, goingfrom 27% (before) to 51% (after) trimming of the bush surface. Cylinders and cuboids had alower performance, which reported an increase of CT between 0.2 and 6 percentage point.The performance of the robot was also qualitatively assessed by human observers byscoring topiaries. The highest score of a single bush is a 3.1 out of 5. These results, com-bined with the quantitative evaluation show that the robot can trim autonomously, but itdoes not reach the required accuracy for practical application. Despite this, the evaluationmethod was able to reveal main bottlenecks of the robot in real-world experiments.Together with the robot description, this paper can be used as a guideline for the devel-opment and evaluation of gardening robots.