Many different plant species can reseed themselves. They are sometimes referred to as reseeders, and they effectively sow their own seeds in the surrounding soil. This self-sown seed results in repeated growth year after year. Reseeders may also be described as "seed propagated plants."
Plant propagation by reseeding is common among many kinds of weeds, so experienced gardeners often concentrate on getting rid of weeds before they can self-sow. More popular with gardeners are self-sowing perennials, such as foxgloves, delphiniums, marigolds, and periwinkles. To encourage desirable plants to reseed, it is important to allow the dead flowers to remain on the plant long enough for the seeds to mature and be shed.
Many species of grass are also reseeders. It is important to note that the ability of grass to reseed an area of soil depends on the grass plants being allowed to grow sufficiently long to shed their seeds. Lawn care practices such as frequent mowing usually mean that lawn grass cannot be relied upon to reseed bare patches.
While most wild plants can reseed, there are some varieties of cultivated plants that are not able to. Corn is one example of such a plant, and it relies on human cultivation in order to successfully reproduce. Genetically modified plants are also often unable to reseed. In addition, many hybrid plants such as a number of varieties of garden flowers, while they may be able to reseed, often produce seedlings that are unlike the parents.
There are many factors that affect how successful a plant is in reseeding. The physical environment is of crucial importance. For a plant to reseed successfully, usually there must be some bare soil for the new seeds to grow in. Certain species of plants will need the soil to have particular nutrients or characteristics for reseeding to be successful. The presence of some substances may prevent a plant from reseeding. An example of this is alfalfa, which is not a good reseeder due to the fact that an old, decaying alfalfa plant produces chemicals that may prevent the new alfalfa seedlings from growing.
Some plants, originally sold as desirable garden plants, are so effective at reseeding that they have become pests. One such species is pampas grass, a prolific seed propagator that can spread rapidly in gardens, along roadside verges, and even onto beaches. This grass species has become a noxious weed in several states of America.