Hi, here in zone 6 NJ delphiniums do return for me, but not super-reliably. Our winters tend to be wet with rain, but not much snow cover. We can get wild temperature changes. I just started a new bed with delphiniums, and was thinking of mulching with wood chips - you know, the big bark ones you can get at Home Depot. My feeling is it might keep the roots cooler during our hot summers, and help stabilize the condition of the roots during temperature swings and wild wet-dry swings. Any reason this would be a bad idea? Though I start them from seed every year (I find if you start early, you reliably get bloom) I'm always trying to increase the number of plants that will come back year after year. Thanks for any advice!