Re: Arilbreds in very cold climates

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    Yes, the + after an OGB means that the iris has a high amount of aril blood.  Even here in my climate, in a raised bed, some of the OGB+ varieties are not reliably hardy.  It depends on whether the greater amount of aril blood is oncocyclus or regelia (regelia is hardier).  The - designates that there is but a quarter aril blood in the mix.  Of the two iris you pictured (nice photos!), Omar's Gold and Persian Sapphire, both of these have SDBs in their backgrounds, and that makes them hardier, in my estimation.  The fact that you grow them in a raised bed has a lot to do with your success.

 

Elm