Hybrid plants can be created by humans, but can also occur naturally as well.
Many plants can mate and hybridise with wild plants of the same species and variety when they are grown in close proximity. Thus, whatever genes both plants had can then be passed on, resulting in a hybrid plant.
However, in some cases, the pollen from a domestic plant may travel a distance, sometimes as long as a few miles, before fertilising another plant. This also results in a hybrid plant, provided that both plants are of the same or closely related species.
In addition, anyone who grows plants at home can easily hybridise their own plants. Plants that are different members of the same species can be cross-pollinated to get hybrid plants. An example of such a plant that is easy to work with is the Lilium. Hybridisation can be done so by collecting pollen from the anthers of a plant and then using a cotton bud, transfer the pollen on to the stigma of another plant of the same species. Also, the stigma of the pollinated plant should be covered to prevent it from being pollinated by insects.