These are Hydrangeas not rhododendron. They vary in color because the soil is both acid and alkaline where individual roots are pulling their energy. Perhaps building debris was left in the soil creating this situation. Perhaps natural limestone is present in the soil. Perhaps someone wanted blue flowers and added sulfur to the soil and did not spread the powder uniformly. In any case, this situation is more common than you think.
Yeah, it's definitely a hydrangea. The variation in color is dependent on whether the soil is acid or alkaline. But Lorraine is right, there are some varieties that bloom multi-colored like this, but there are others that bloom in a single color like white, blue, cream, and a beautiful red. They are a favorite old time flower.
Yes Jim G Hydrangea macrophylla (mophead hydrangea) are perennial shrubs, deciduous in your area and semi-evergreen here in Central Florida. They vary in height according to variety, usually under 4 feet. They like moist soil that is well drained and grow best if protected from the hot afternoon sun. They bloom on last years wood, so don't cut them to the ground each year. Trim only dead or damaged branches and trim off old flower heads. Light trimming of height to keep them inbounds will not prevent them from blooming.
To Connie H (Wimauma, FL): The article was actually given to me by the lady who wrote it...Anne G (Chicago, IL). The videos were at the bottom of the article. Thanks again, Anne G!
To Jim G of Suffolk, VA; Janice H of AL; Connie H of FL; and Nancy Rhodes C of Bessemer, AL: Thank you all for your comments. I'm glad the link has been so helpful to so many. It was very kind of Anne G (the author) to allow me to pass it along. Have a wonderful 4th!
Hydrangea don't tolerate dry heat. They love moisture and some shade. What ever you do don't prune cause they bloom on old wood. This variety is Endless Summer and they grow slow.
how much water do they need?
http://themicrogardener.com/how-to-grow-hydr...#