Gardeners are humans found in Falador Park. They look after the flowers and other various plants found in Falador Park. They will exchange White lily seeds for 100 Farming experience. They will only take 50 seeds per day.
A gardener will attack you during the Pirate's Treasurequest, when you dig for the chest in the plants, but you can avoid this by running away and returning some time later. During Pirate's Treasure, the gardener that attacks you will talk about moles digging up the garden.