heirloom plant

heirloom plant, any plant cultivar that has been grown for a certain number of years and that breeds “true to type” from seeds, with each generation of the plant having the same combination of traits. There is no agreement on the precise criteria for heirloom plants. According to some definitions, an heirloom plant is one that has been cultivated for at least 50 years, while others maintain that it is 100 years. Still others assert that an heirloom plant is any cultivar developed before the end of World War II, or, specifically, before 1951, when hybrid crop plants were widely introduced. In general, an essential criterion of the “heirloom” label is that the cultivar was grown and maintained by a family, community, or other group, with the seeds passed down from generation to generation. While the term is often used for fruits and vegetables, many ornamental garden flowers are also considered heirloom plants. Popular heirloom plants include tomatoes, beans, corn (maize), lettuce, melons, okra, collard greens, sunflowers, zinnias, and foxgloves.

Prior to the industrialization of agriculture, heirloom plants were the dominant crops worldwide, with some heirloom cultivars having been grown for hundreds and even thousands of years. Heirloom plants are open-pollinated, which means that the wind, birds, humans, or bees or other insects pollinate the plants with pollen from different individuals of the same variety. The resulting generation thus breeds true, with roughly the same characteristics as the parent plants. Throughout history humans have selected and saved seeds from the healthiest and most vigorous plants and thereby gradually developed a myriad of unique heirloom cultivars that are accustomed to the soil, climate, and pests of a given region. See also plant breeding.

In contrast, the hybrid cultivars used in industrial agriculture are bred for maximum yield, producing vegetables that have a uniform appearance, are resistant to diseases and pests, and hold up well during shipping. They are created by crossbreeding two different plant varieties of the same species, and their seeds do not produce plants with the same characteristics as the hybrid parent plants (i.e., they do not breed true to type). Because of this, gardeners and farmers must purchase seeds every year. Genetically modified crops are also used in modern agriculture, and, regardless of whether they breed true or have been in cultivation for decades, they cannot be considered heirloom crops.

Although heirloom vegetables generally are not as disease-resistant or productive as many modern hybrids, many have been selected for their superior flavours, and their colours and shapes are aesthetically pleasing. In addition, many heirlooms are also exquisitely adapted to the region in which they were developed and hold valuable genetic resources, such as drought- or heat-tolerance, that can be useful in the breeding of hardier varieties. Specific heirloom plants often have a story—a relationship with the past—that serves as a connection to a cultural heritage. Many Indigenous peoples, for example, have prized or even sacred heirloom crops that have been passed down for generations, sometimes surviving genocide, colonization, or other existential threats.

Given the cultural and genetic importance of heirloom plants, interest in cultivating them has increased since the late 1900s. Without seed-saving efforts, many heirloom crops are at risk of being lost forever, and countless cultivars have undoubtedly already disappeared. Individual hobbyists and nonprofits, as well as traditional farmers around the globe, actively work to keep these resources in production. Indeed, heirloom seeds are so important to the global food supply that since 2008, the seeds of more than one million heirloom cultivars have been stored in the Svalbard Global Seed Vault on the remote Norwegian island of Spitsbergen. A comprehensive storage facility, the vault serves to protect the genetic diversity of humanity’s food crops from the threat of a global catastrophe, such as nuclear war, and to safeguard genetic resources that could be used to breed new varieties that are adapted to a changing climate or a novel plant disease.