ID? - Supposedly 'Mounds of Snow'

I have several cultivars of hydrangea I bought last year. They're all true-to-expectations except one. I bought this one as 'Mounds of Snow,' supposedly a mophead-type that stays white regardless of soil composition. Instead, I've got a lacecap-type that's light pink. One distinguishing characteristic of this one is that the stems are red in color. I wanted to think it was hybridized with Annabelle - since it was supposed to stay white - but now I have no idea.

Any thoughts on what I have? Thanks...

Do you have alkaline soil? Our 'Lady in Red' has very noticeable red stems but blue lacecap flowers in our acid soil. An alkaline soil would have flowers in the pink range.

That's a thought, for sure, pirl. Thanks for the reply. I didn't put it in the ground - just in a larger pot - until it gets better established, because I bought it as a small starter plant. It's very possible the potting soil turned it pink because I've got others in pots that are light pink, also...cuttings I rooted from other plants, in the same potting soil. When I think back to ordering this, I was skeptical of any macrophylla that "stays white." Maybe I'll find a true Annabelle / arborescens this year to try, because I don't have any whites. I enjoy adding to a collection. Others I grow are Glowing Embers, Cardinal Red, Emile Moulliere, Nikko Blue, and Mariesii Variegated. I'd love to try PeeGee's, but I don't get enough sunlight. Regardless, I'm still happy with any new hydrangea. :o)

I don't have Annabelle only because around here they flop so much and look so dreadful after a rain. They do remain white. You could try Limelight, which starts off a greenish white and then turns white.

It's so easy to love hydrangeas!

Here's my favorite one, Beni Gaku, along with two photos of Limelight, a gift from a friend.

A lot of "white" macrophyllas are actually very pale pink or very pale blue depending on your soil pH (will often look fairly white from a distance, but if you look close you'll see the pink or blue tinge). But since Mounds of Snow is a mophead and yours is clearly a lacecap it was definitely mislabeled.