Grade-size standards for nursery stock are set for which of the following?

The grade-size standards for nursery stock, including rose bushes, are established to ensure quality and consistency in the plants sold to consumers and retailers. These standards help assess the suitability of plants for landscaping and garden use, dictating parameters such as size, shape, and overall condition.

Rose bushes are particularly significant in these standards because they are one of the most commonly cultivated ornamental plants. They have specific grading criteria to determine their vitality and marketability, which influences how they are marketed and sold within the industry. Standards for rose bushes ensure that consumers receive healthy plants that are likely to thrive once planted, which is critical for both consumer satisfaction and the reputation of the nursery.

Additionally, while other options are also important in horticulture, they do not typically have the same established grade-size standards as rose bushes. For example, citrus trees have their own set of cultivation guidelines but may not be graded the same way as ornamental stock. Herbaceous plants and annual flowers also contribute to a nursery's offerings but do not generally follow specific grading standards to the extent that rose bushes do. This focus on roses reflects their prominence and the industry's need for a reliable quality standard.