It's probably too comfortable-it would have performed better in poorer quality soil,and with a little less water.
Try it next year!
(remember that these types of plants are magnets to aphids,so invest in some insecticidal soap,and be prepared...they will leave the plants messy looking)

I agree that ignoring this plant can be an advantage. Mine is in a very neglected corner where it was just plopped in - it gets virtually no attention other than a seasonal clean up and very little supplemental irrigation. It bloomed like a maniac earlier, got cut back and is now producing another massive bloom stalk. I've not had a problem with aphids although the resident slug population does value the lower foliage :-) That's OK - there's more than enough to share.

It has been a VERY dry summer, perhaps 2.5 inches all summer, so it's not too much water. The soil is rich, but I swear I've seen them growing in English gardens next to delphiniums and other rich soil lovers.

My soil is pH 7.1, so do you think alkalinity bothers it? The foliage looks healthy.

Do you think it's necessary to move it to a poorer soil?

Thanks!

I read that Crambe don’t like to be close to other plants and need space around them. Since I moved mine it’s bloomed very nicely

The giant I saw was growing between slates on an ungodly hot patio.