Lisa, these are so beautiful in bloom.
How many bulbs do you have?
You might want to late-fall dig all but one or two and see if those that winter in the ground are happy in their location.
We all have so many variables to position/light/drainage and water supply in our gardens that it's tough to advise.
I read that Zwanenburg is hardy in Zone 9-10.
We all love to push the zones but there's a risk that a wet, unusually cold winter will create mush out of our favorite flower bulbs left in the ground.
Trial and error but were I you, come late fall I'd be digging up most of these and storing them according to researched instructions.

Dottie, i bought 9 at costco of all places. i really try not to buy plants or hardware from big box stores, but they just looked so pretty on the package. They're really pretty in the garden. not sure they will work as i intended - to go with the agapanthus as they are just about done blooming. do they make more bloom stalks or do you think they're done for summer?
lisa

Costco Matthews by chance? Never fails I'm always in the checkout line when I notice the plants and bulbs.

yes, matthews, lol.

My Zwanenberg survived the "Snowpocalypse" and an unusually cold winter in Birmingham, AL, zone 8.

Susan