Pistachio is the trade name (name under which it is marketed) for the cultivar Hydrangea macrophylla 'Horwack'. Similarly, 'Schloss Wackerbarth' and Glam Rock seem to be the cultivar and trade names of a different H. macrophylla.

Tony Advent (owner of Plant Delights Nursery) wrote this explanation, "The current improper use of trademarks in the horticultural industry had its origin more than a half century ago. The worst culprits, in the early years, were the rose and bedding plant industry. The rose industry seems to have been the first to use nonsensical, non-conforming names for plant cultivars, while the bedding plant industry completely thumbed its nose at the Code by not even bothering to come up with any cultivar names for most of their introductions. One of the most famous roses in horticulture is one that everyone knows as Peace. Surprisingly, there is no such plant as Rosa 'Peace'. The plant we grow under this name is actually Rosa 'Madame A. Meilland'. The trade name Peace was coined by Conard Pyle Nursery, and used to market Rosa 'Madame A. Meilland' after World War II to capitalize on the post-war sentiment. The plant became known in the public's mind as the Peace rose. Some of the larger nurseries soon realized that regardless of the cultivar name of the plant, they could come up with their own proprietary (trademarked) marketing name and use these names to promote plants which already had valid cultivar names. The idea was to convince the public that the company's marketing name was actually the name of the plant. The next step in the downward spiral was when nurserymen began intentionally giving their new plants stupid nonsensical cultivar names. Subsequent plant promotions would often only tout the marketing name, causing the consumer to often not realize the plant had a real cultivar name. The cultivar name, if included at all in ads and tags, would be printed in very small print in comparison to the "marketing name". The entire idea is for the company's marketing (trademark) name to become the generic name of the product in the consumer's mind. The practice of using nonsensical names violates the entire purpose for having an International Code of Nomenclature for Cultivated Plants while the use of trademarks as generic names violates the legal use of trademarks." You can read the rest of the article on the Plant Delights website.

I don't know a lot about the rules for plant cultivar names, but this whole thing of having the cultivar name and a cutesy marketing name adds a great deal of confusion to the process of IDing plants. To be technically correct, one should put the cultivar name in single quotes and the trade name not.

• Hee hee hee. Yes they are confusing and trying to confuse us in order to make a buck. They come up with cryptic names like Horwack or even worse (bunches of letters and numbers) when developing plants. Resellers then change the name sometimes. The name on the patent for this shrub is Horwack though. This is especially common when the shrub originates from outside of the US with a name "x" and is then given a different name 'y' in the US. For example, close your eyes and think: would you prefer to buy a hydrangea called Schloss Wackerbarth or Pistachio? Other times, a poorly selling shrub is given new life by changing its name. And that... is another story.... ;o)

It's sold as Pistachio in USA. Mine had a Ball Horticulture "Next Generation" label on it.

I think BH and-or Monrovia are using that 'Next Generation' term to group certain hydrangeas that they are selling. Other grouping names used by other companies: Lets Dance, Endless Summer, Gatsby, etc.

fyi - in case you are wondering, they changed the name of the Endless Summer mophead! The collection or grouping is now the one that is called 'Endless Summer'. The original mophead that was called Endless Summer is now called 'The Original'. Other names that are part of the 'Endless Summer' Series/Grouping/Collection are: Blushing Bride, Twist N Shout, Bloomstruck, etc.

Perfectly legit. And sadly, perfectly confusing too!