The Lily of the Valley has been doing well in my garden for over 20 years. It was already here when we moved in and each year multiplies along the North East facing narrow border outside the garage.
It seems to thrive on neglect as I have never touched it other than to pick some stems to display indoors in vases.
It would probably do even better if I divided up some of the clumps and distributed them around the garden in shady spots. It is at its peak during May and its scent wafts around the garden and is enhanced by the warmth of the sun.