In m Shiva wrote:
What has been different this year is:

1. LOTS of rain.

Shiva, too much early watering has killed rose bushes for me. My
drainage sounds worse than yours, having predominantly clay soil, but
I've found that a little moisture is much better than a lot.

I've got (possibly) some marginal benefit by using plant starter
solution on my new plantings.

Having said all that, it looks like my bare root Benjamin Britten and
Ernest's Blue roses are going to suffer infant mortality. This I blame
entirely on the supplier, who shall remain nameless for now. The bushes
were too tiny to be 2 years old - a case of rushing new varieties to
market, I would suspect. Their root systems were barely there. Not
happy....