A nursery is a place where plants are propagated and grown to a desired size. Mostly the plants concerned are for gardening, forestry, or conservation biology, rather than agriculture. They include retail nurseries, which sell to the general public; wholesale nurseries, which sell only to businesses such as other nurseries and commercial gardeners; and private nurseries, which supply the needs of institutions or private estates. Some will also work in plant breeding. Some nurseries specialize in certain areas, which may include: propagation and the selling of small or bare root plants to other nurseries; growing out plant materials to a saleable size, or retail sales.[4] Nurseries may also specialize in one type of plant, e.g., groundcovers, shade plants, or rock garden plants. Some produce bulk stock, whether seedlings or grafted trees, of particular varieties for purposes such as fruit trees for orchards or timber trees for forestry. Some producers produce stock seasonally, ready in the spring for export to colder regions where propagation could not have been started so early or to regions where seasonal pests prevent profitable growing early in the season. There are a number of different types of nurseries, broadly grouped as wholesale or retail nurseries, with some overlap depending on the specific operation. Wholesale nurseries produce plants in large quantities which are sold to retail nurseries. Wholesale nurseries may be small operations that produce a specific type of plant using a small area of land, or very larger operations covering many acres. They propagate plant material or buy plants from other nurseries which may include rooted or unrooted cuttings, or small rooted plants called plugs, or field grown bare root plants, which are planted and grown to a desired size. Some wholesale nurseries produce plants on contract for others which place an order for a specific number and size of plant, while others produce a wide range of plants that are offered for sale to other nurseries and landscapers and sold as first come first served. Retail nurseries sell plants ready to be placed in the landscape or used in homes and businesses