Volunteer plants

Volunteer plants are plants that grow on their own from seed that has not been planted purposefully. The term is used in gardening and agronomic contexts.^[1]

Volunteer plants are most often considered desirable (for example, tomatoes, spinach, parsley, lettuce, carrots, dill, flowers, etc).^[1]However, in the case of other plants, such as tree seedlings or invasive species, they may be considered weeds.^[2]

Such plants are often quite strong and healthy. While a volunteer plant may be welcomed by the gardener or farmer, it may not be growing in an ideal location in the garden or field and the gardener may need to intervene and shift the plant to a more suitable position. If so, care must be taken to do this while the plant is still young and to so with the plant's needs accounted for.

• Wikipedia:Volunteer (botany)