It can be. Here are a few thoughts.

1. To get and maintain purples, your soil has to be in a narrow layer of soil pH that is difficult ��"but not impossible- to achieve when planted on the ground. Add garden lime per label directions if your soil is already acidic. If your soil pH is already alkaline, add garden Sulphur, green sand, iron sulfate or aluminum sulfate per label directions. Your own soil will govern how well and which shades of purple you can get when you amend.
2. It is easier to control soil pH when you grow them in containers. In the ground, you could end up with purple sections in the bush⦠with other areas with a slightly different color (blue/pink) or shade of purple if some of the roots do not absorb the necessary minerals in the same amounts as other roots.
3. Named varieties with the word "purple" will produce good and deep purples. Glowing Embers, Enziandom, Purple Tiers, Purple Passion, Royal Purple, Nightingale, Mathilda Gutges, Marechal Foch and Merritt Supreme can give you nice purples. Enziandom leaves turn nice colors at the end of the growing season. Nightingale produces a lot of bloomage per stem. The named varieties given above produce blooms only in the Spring.
4. Colored re-blooming hydrangeas can also be useful but, they will not necessarily give the deep purples of the above named varieties. Example: the Endless Summer Series or the Forever and Ever Series. The good thing about rebloomers is that you get blooms at multiple times throughout the growing season and, as each set of blooms opens, you can see the result of changes to the soil pH, compared to the previous set of blooms. If new blooms in May were pink and if new blooms in June-July were blue, that means you have amended too much and need to tweak the soil pH in the opposite direction. So, it may take less time to get the purple shade that you/she want if you have colored rebloomers.
5. You can choose from many hydrangea macrophyllas or serratas but you will need to keep and eye on their winter hardiness (you are in Z5). Most if not all will need winter protection if planted outside in the ground. If planted in a container, you will need to bring the container into the garage or similar place during the winter months and water it once every week or once every two weeks.
6. Full sun exposure⦠it may cause the color not to be as deep as it could be because the sun may bleach the blooms a bit. Hydrangeas must have afternoon shade (or the leaves will suffer from too much sun) here but, your not-as-strong summer sun in NY may allow you to grow them in full sun. If no one in your zone & location comments, I would drive around looking for similar colored (blue/pink/purple) hydrangeas and see where they were planted (sun-wise) and if they had winter protection.

Luis

Full sun is NOT a good situation for any hydrangea that produces blue or purple flowers - Hydrangea macrophylla. These are plants that prefer at least part shade (afternoon shade for sure). Even in my far north, weak sun location, established hydrangeas in full sun wilt on a daily basis.

I'd also question some of the suggestions for a 'dark purple' color - Glowing Embers is known for its very stable pink coloring regardless of pH......you would need some seriously acidic soil to generate a deep purple from that variety. 'Purple Passion' is a marketing name assigned by Michigan Bulb......they like to rename anything they sell according to their whim. The correct name for this plant is 'Royal Purple'. But the purple coloring will only occur on this and other "purple" named forms if the soil is sufficiently acidic.

They won't have purple flowers but the best hydrangeas for full sun are the paniculatas. And soil acidity is really not much of a concern with these varietries as well.

Thanks for the suggestions. I should say that it's not 100% sun. Kinda forgot that in our front yard there will be some afternoon shade. They will get pounded with sun until mid afternoon though. I will take the names along with me when I make the annual Mother's Day trek to the garden center. Thanks again. Ed.