Finally, I visited Baltimore's largest garden, the Cylburn Arboretum , and was treated to a tour by head gardener Jennifer Forrence and board member Nell Stratchan (Nell's also on the board of the Horticultural Society of Maryland). Curiously, both have law degrees!
About the Cylburn
Interesting history here, how a 207-acre estate started as the private estate of the Tyson family (in the chrome business, not the chicken business), the home having been built in 1863 for Jesse Tyson and his mother. In 1942 the family donated the estate to the city and it served as a "home for neglected children" until 1954, when it became a city park.
There are all sorts of special collections (magnolias, cherries, hollies, boxwoods, viburnums, etc), and a vegetable garden that's tended by Baltimore Master Gardeners.
The Cylburn is FREE to everyone and open every day of the year. And it has a pretty full calendar of events, including its guided walks and nature story hours, as well as the lecture series put on by the Maryland Horticultural Society. Check it out!