Ask Mr. Smarty Plants

It does sound as if your roses are being affected by the salt accumulation from your water softener so it sounds as if you need to make some changes to your system. The mechanics and functioning of water softeners are far outside our area of expertise, but here is some information about how to reduce environmental impact of water softeners from Monterey Regional Water Pollution Control Agency (Monterey, California). Your best bet, it would seem, is to contact the manufacturer of your particular water softener to see what your options might be; and you might also do some internet research to see if there are water softeners that are saltless.

To make your roses healthy again you probably are going to have to replace a goodly portion of the affected soil. However, here are some other remediation options for saline soils that you might like to pursue further. One is from Colorado State University and addresses the problem of high salinity caused by irrigation water and is called Soil Salinity: Assessment and Remediation. The second possibility accomplishes soil remediation using halophytic (salt-loving) plants.  If it is possible to water your roses with unsoftened water, that is the best course of action you can take.

Finally, it is possible that your roses are simply afflicted with one of the many fungal diseases common to the genus.  The rainy weather in your area this year has created ideal growing conditions for many of these fungal pathogens.