I came across the article below over on the Wikihow website, which gives great details on planting and caring for your hydrangeas, and how to get the colors that you want. You will also find instructions on how to preserve and dry your flowers, so that you will have a beautiful dried arrangement to last a long time.
- Mophead and lacecap hydrangeas, or “bigleaf” hydrangeas, grow well in zone 8, which has a warm climate. They don’t do as well in colder regions unless you take measures to protect them from frost.. Look for the “Endless Summer” mop-head variety at your local nursery – it’s a type of mophead hydrangea that blooms more than once over the summer. This type of hydrangea produces large balls of pink or blue blossoms that deepen in color over the course of the season.
- The oakleaf hydrangea grows well in places with very hot summers without too much moisture. It is hardy through zone 4b/5a.  This type of hydrangea has white blossoms.
To read the full article go over to the Wikihow website.