E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Prudent Tree (The).
Pliny calls the mulberry the most prudent of all trees, because it waits till winter is well over before it puts forth its leaves. Ludovico Sforza, who prided himself on his prudence, chose a mulberry-tree for his device, and was called Il Moro.