That is a tough question because of the process that is involved.

The true flowers in the center of the lacecap blooms can be pollinated and this will make them change color and produce seed pods. At the time this happens, the sterile sepals that surround the center's true flowers will rotate and change color.

So we could both have the same type of lacecap hydrangea. Yours might be able to hold the color longer than mine if pollination in your shrub occurs later.

Luis is right ~ Mother Nature rules! There are many factors that have to be considered (zone, sun-exposure the shrubs' basic habit of budding & flashtime etc) I have several H serratas that I have been observing closely ~ particularly, time between bud to flash, color convertibility & changes.

Blue Frost ~ I must have planted in an ideal site (in AM sun/bright shade) is my earliest budder(end-Apr to mid-May) bloomer (early-Jun to mid-jun) & most floriferous as I noted since planting in '08. Today the center has fuzzed up & starting to dust around. In a few weeks the infertile petals will start the characteristic, rotation slowly as well as turn to the pink & by fall into merlot (including foliage). From observation, also throws a few blue caboose late in season.

You should check out Blue Billow, Blue Bird & Blue Deckle (My Twist & Shouts are starting to show up blue on the new blooms produced after I have clipped all of the nursery produced ones).

I never thought of it that way, but it makes sense. Is there like an "in general" choice though? I'm in zone 7 (Long Island).

Blue Wave is impressive online, but I'm having trouble finding one locally for sale.

Bruce

Midnight dutchess is a great lacecap with black or eggplant stems on the new growth, it's not blue more of a mauve but fantastic.