] Henry even chuses the method burn your hand(eg search the cabinet for laundry bills) and discover your silliness.

So does his creator. I won't put any spoilers for NA, though it is a clear case with Catherine, but everywhere else in JA's novels people learn about life from life directly, not from any reasoning of any guru.

] From what I know, there are several meanings to the rose over the centuries.
] While it was grown in monastries because of medicinal uses, the ancient greeks saw it as a symbol of innocent youth, of life in bloom. It was then the flower of Aphrodite, godess of love. The Romans however came to look upon it (Cicero)as connected to a life of idleness and depravation.

Hmm, and sub rosa, one of few Latin phrases that I still remember? A symbol of silence, then.

] Later on it was connected to the worship of saints, the rose turned into a symbol of the Virgin Mary.
] During the Middle Ages it was obviously used by bride and bridegroom in wreaths and by the nuns also(heaven's brides) when they joined the convent.
] Through the ages roses have been cultivated in great numbers because of the many uses man have assigned them.

I'd like to know about medicinal uses. Rose oil in perfume is an obvious use, of course, all due to (comparative) easiness of getting it out of the flower.

] How are we to decide what Henry was thinking? Is there a particular symbolism in Georgian times?

Well, I've looked into this question of language of flowers, and got entangled between periods. No direct source for Regency, sorry. But in some sources the "meaning" of rose depended on the colour of the flower, from white ("innocence", the only colour suitable to give to a young girl) to bright red ("flame of passion", impossible to be presented socially).