The tree can grow up to 12 metres in height, and the plant is very sensitive to frost. Longan trees require sandy soil and temperatures that do not typically go below 4.5 degrees Celsius . Longans and lychees bear fruit at around the same time of the year.
The longan is so named because of the fruit's resemblance to an eyeball when it is shelled . The seed is small, round and hard.
To express longan fruit, Vietnamese has a wonder: ''Da cóc mà b?c b?t l?c, b?t l?c mà b?c hòn than'' : toad's skin is the ugly skin, tapioca wheat is the clear white flesh and coal ball is the black seed.
The fruit is edible, and is often used in East Asian soups, snacks, desserts, and sweet-and-sour foods, either fresh or dried, sometimes canned with syrup in supermarkets. The seeds of fresh longan can be boiled and eaten, with a distinctive nutty flavor.
Dried longan are often used in Chinese cuisine and Chinese sweet dessert soups. In Chinese food therapy and , it is believed to have an effect on relaxation. In contrast with the fresh fruit, which is juicy and white, the flesh of dried longans is dark brown to almost black. In Chinese medicine the longan, much like the lychee, is considered a "warm" fruit.