"Four Excellencies of海棠" refers to what? A detailed introduction to the "Four Excellencies of海棠".

West府海棠. Rosaceae, Apple genus. Although haitang flowers are beautiful and attractive, most haitang flowers have no fragrance, except for West府haitang, which is both fragrant and beautiful, making it the superior grade among haitang flowers. The flowers of haitang are large, with four to seven flowers in a cluster, all facing upwards, the buds are bright red, similar to dots of rouge, and after blooming, they gradually turn pink, like the dawn's rosy glow. They have very high ornamental value. The fruit of West府haitang is called haitang fruit, which is sweet and sour, similar in taste and shape to hawthorn, and can be eaten fresh or made into preserves.

Weeping haitang. Rosaceae, Apple genus. Weeping haitang has a loose crown and a graceful posture. The leaves are alternate, ovate or elliptical, with fine saw-tooth edges. The flowers form an umbellate raceme, with four to seven flowers in a cluster hanging down, the flower stalks are thin and long, red before blooming, and gradually turn pink after blooming, mostly semi-double, and there are also single flowers. It is suitable for planting on both sides of small paths, or alone or in groups on lawns, and it is best planted near water. It is as beautiful as a beauty reflecting in a clear pool, delightful to the eyes. When the fruit of Weeping haitang ripens, the fruit is red and yellow, exquisitely lovely, mainly used for ornamental purposes, but can also be eaten.

Thicket haitang. Rosaceae, Loquat genus. The leaves of Thicket haitang are ovate or elliptical, with three to five flowers in a cluster, short and thick or nearly stalkless flower stalks, hence the name Thicket haitang. The flowers are pink, crimson, or white, blooming before or at the same time as the leaves, with a flowering period of three to five months. When in bloom, the Thicket haitang flowers are in clusters of three to five, crowded together, creating a lively scene. The fruit is called wrinkled loquat, also known as Sichuan loquat or Xuan loquat, ovate to spherical, yellow or yellow-green, fragrant, almost stalkless, ripening in August and September, and can be used as medicine. Thicket haitang is an excellent ornamental and fruit-bearing plant, one of the main spring flowers in gardens, which can be planted individually in gardens to create a flower border, planted in rows to form a flower hedge, or used as a potted plant, making it an ideal material for creating flower tree stake盆景.

Papaya haitang. Rosaceae, Loquat genus. The leaves are ovate or ovate-oblong, with thorn-like fine saw-tooth edges, and a thick leaf stalk. The flowers bloom singly at the tip of short branches, with short and thick stalks, hairless, petals are inverted ovate, light red or nearly white. The flowers and leaves bloom simultaneously from March to April. The fruit is a long ellipsoid, deep yellow, glossy, the flesh is woody, slightly sour and astringent, fragrant. The seeds of Papaya haitang are edible and can be used to make soap. The fruit, after steaming, can be made into preserves or used as medicine, with the effects of expelling wind, smoothing qi, relaxing tendons, and stopping pain, and can also relieve alcohol and phlegm, and stop diarrhea. The flowers can be used as an ingredient in sugar-based sauce, which is very delicious. The bark contains tannin, which can be extracted to make tannin. The wood is hard and can be used for making furniture. Additionally, this species is also excellent for garden绿化.

The above information explains what "海棠四品" means and offers a detailed introduction to the experience and knowledge of the "Four Grades of Haitang." I hope this article can provide you with some help!