Ask Mr. Smarty Plants

June 2, 2008 we answered a similar question about your plant, although that was in Texas. However, this does sound like a similar situation, so here is an excerpt from that previous question:

"Indigo Spires, sometimes called Mystic Spires, is thought to be a hybrid between Salvia farinaceae and S. longispicata. It was found growing at the Huntingdon Botanical Gardens in California in the 1970s. The botanist who discovered and named it noticed that it the new plant was growing near the other two, and theorized that it was an accidental hybrid. Salvia farinacea (mealycup sage) is a Central Texas native, but the S. longispicata is something of a mystery, thought to be native to Mexico. In fact, when we went googling to try to find information about it, it was always in combination with S. farinacea to make Indigo Spires. When you're unclear about the parentage of a plant, it is very difficult to diagnose problems or recommend care. So, we found some facts, including in our Native Plant Database, about S. farinacea, and hope they will apply to the mix of two salvia. We learned that salvias hate to have wet winter feet, but also hates having roots dry out and will quickly die when that happens. If your salvia was in a poorly drained bed, it might be suffering from drowned roots. It's more likely, however, since we didn't have much winter rain, that the salvias are suffering from being dried out. You are going to need to trim out the upper part of the plant anyway, to take some of the strain off the roots, and then make sure it has moist soil around the roots. Under ordinary circumstances, it is advised to cut back old flower stems when new basal foliage begins to appear. Don't fertilize until the plant is recovered, if it recovers, and we hope it does. Just as an aside, hybrids like this are sterile, or their seeds will not breed true to the original plant. If you wish to propagate it, take stem cuttings."

On July 4, 2008 we had another similar question, again, in Texas. 

"Having said all that, let's try to figure out why your new plant is not doing well. The instructions in the various sites we looked at about "Mystic Spires" indicate that it needs some good humus in the soil, especially if it is clay. In fact, one of these plants in a poorly draining clay soil will probably not survive cold weather."

That may be the key to the problem. Whether they can be saved this year, we have no way of knowing.  Give some of the stems the thumbnail test-scratch a little of the outer surface off and see if there is a thin layer of green beneath. Do this very low on the plant, as it ordinarily dies back to the ground in the winter. If you feel there is any life left in the roots and are willing to spend the time, you could dig them up, doing as little damage to the roots as possible. Refurbish the soil with some good quality compost, for the drainage in clay soils mentioned above, and tenderly replant the roots. Give them some consistent, gentle watering, dripping very slowly deep into the soil. Trim off most of the upper material before you replant, as it is probably all dead anyway, but leave enough to identify where the plant is. Don't let the water stand on the plant, that will be insult to injury. If they don't survive, and you really like the plant, you can buy some fresh ones, put them in that lovely composted, well-draining soil, and avoid this loss next year.

Pictures of "Mystic Spires" Salvia