Currently, there are 550 species of grasses grown in the Grass Garden, but this number is being added to continuously. Seeds, offsets and leaf material are dispatched to other botanic gardens, universities and research institutions around the world. Grasses are easy to cultivate, and there are hardly any problems with pests and diseases.
Some fungal diseases do occur, however.
Many grasses can also act as hosts to particular fungi, which then serve to keep potentially more harmful pests at bay. The best times to visit the Grass Garden are early summer for the annual grasses and cereals, and autumn and winter for the perennial grasses when these have produced their seedheads. A grass is described as perennial when it lasts for more than one growing season. The season of greatest interest for annual grasses is early summer. Every autumn, seed is gathered from the annual grasses and then sown in a cool glasshouse in March or early April.