Regency Romance, Adopts Girl, Falls In Love

I'm looking for a regency romance about a British aristocratic man who keeps a promise to a friend and brings a girl from rural Russia back to his estate. At first, the girl is wild and cannot speaks English so she only befriends the gardener, who tends to roses. The man is cold to her. The man initially has a crush on another woman, maybe an actress, who refuses to be his wife but stays his mistress. There is a special kind of rose the man keeps in his garden in honor of her. Gradually the man warms up to the wild girl and they fall in love. There were attempts to assassinate the girl, who in the end turned out to be the illegitimate daughter of the king. The man arranges for them to be left alone in exchange for never revealing her identity.

Any help to identify this book will be greatly appreciated! I read this many years ago (a beaten up paperback from the local library) and have been searching for it ever since!!

A Most Reckless Lady sounds like it might be your book...Amazon summary mentions roses.

Yes indeed it is. Thank you so very much!