You would need at least 3 hours to walk the entire property, and it's better to have more time because the park is a long rectangle and there are many unique places you'll want to sit, rest, relax, and just enjoy looking around. Many areas do not have shade, so I would caution against visiting between 11am and 2pm on a very hot summer day. We loved the Butterfly House, the Japanese Garden and the turtles! The Rose Gardens are very open and hot (as many roses thrive in full sun) and that was tiring. The grounds are beautiful and there are some wooded paths that run along the perimeter, but not along the entire park. Beautiful spring, summer or fall. They have a drive-thru lights display at Christmas, but we've never done that.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.