This is a photo of me from one of our trips to Longwood Gardens. You can see how happy I am with the beautiful colors and scents of fresh flowers all around. This was taken in one of the huge indoor exhibits in the Conservatory. You can visit all year long and see amazing displays outside and inside.
They recommend that you plan at least 3.5 hours to visit the gardens, but if you have the stamina you can use an entire day. It is a good deal to join as a member, then you can visit as often as you like. The exhibits are changing often and they are all wonderful.
Even though there is a lot of walking to see the various areas and exhibits, they do rent scooters for people who do not have their own way of ambulating around the park.
There are education events and programs for all ages, and they are well done. They even have high level botany classes and research.
The history of the park, the duPont family, and the trees and buildings is also very interesting. They have displays and a movie to show you the growth of the gardens from the first plans forward.
Longwood Gardens is located in Kennett Square, PA. This is a suburb of Philadelphia close to the Delaware border.
I highly recommend a visit, at least to the website if not in person.
You can see a lot of information and photos about the gardens at their website.