Additional Huntington Gardens images can be viewed here.
One of the best times to shoot is from a half hour to 2 hours after sunrise. The mottled light making its way thought the trees to highlight the subject foliage can be fascinating. It is constantly changing so a scene one minute may look totally different a couple minutes later. Also, early admission for members provides an extra dose or serenity which is very conducive to creativity.
I also have to give some credit to the camera sensor manufacturers. The new 3rd generation sensors have much higher dynamic range than earlier generation sensors. Thus, images of scenes with contrasting lighting are much more capturable. Of course, shooting earlier in the day also helps along with some exposure blending in post processing. All of a sudden, capturing the image above wasn't so simple although it looks simple.
The image above was shot with a cropped frame DSLR with Sigma 17-70 mm zoom lens, F8 at ISO 800, on carbon fiber tripod.