Vi I am so sorry to hear that! I have no experience dealing with borers.
Comanche Acres Iris Garden sells a spray for iris borers:
http://www.comancheacresiris.c...
If you prefer to try a non-chemical solution here is some information on Nematodes from a page (from University of Minnesota) on iris borers:
"Beneficial nematodes are a natural option to help control some boring insects. These nematodes are microscopic worms that seek out and kill the caterpillars by introducing a bacteria. Research results using nematodes have been inconsistent, although they can potentially be effective in reducing iris borer populations.
Two species of nematodes are commercially available from natural garden supply catalogs or your local garden center. Both species (Heterorhabditis and Steinernema) have been shown to attack iris borer. Nematodes need a moist environment to survive and move. The easiest time to apply is during a rain shower. Lacking rain, water iris before and after applying nematodes. Apply nematodes when iris leaves are almost fully expanded but before flowering. Repeat the treatment approximately one week later. Nematodes are perishable; check the label for the expiration date."
Source:
http://www.extension.umn.edu/g...
Here is the American Iris Society page on Pests and Diseases of Irises, it has a section on borers:
http://www.irises.org/About_Ir...
And finally a page from the Missouri Botanical Gardens on iris borers:
http://www.missouribotanicalga...
When you get things back under control...or next spring if the timing is better I can sent you a rhizome of Boysenberry Buttercup.
Good Luck!
