The original text is Zhilan yushu 芝蘭玉樹 [angelica, orchid, and jade trees], meaning promising or successful offspring.
Zhilan 芝蘭, the same as zhilan 芷蘭 [angelica and orchid], is the metaphor for virtuous characters.
Baizhi 白芷 [angelica dahurica]
Lan 蘭 [Orchid]
Yushu 玉樹 [jade tree]. Yu 玉 [jade] holds great cultural significance in China and is often used to refer to a virtuous gentleman. Jade and jade products have gone through changes from ritual utensils to symbols of power and later to objects of leisure appreciation. More about the culture of jade, see https://rlbwg.xmu.edu.cn/info/1015/1044.htm
