Q. I had a beautiful sage plant that seemed to be growing well, but all of the sudden it just wilted and died. What could have caused this? 

If you have a drip irrigation system, check that first. Drip irrigation is wonderful, but the main disadvantage is that the first sign of failure is a dead plant. An emitter may have become clogged or twisted shut. A leak anywhere in a drip line will cause a pressure drop, which will cause all emitters on that line to fail. If neighboring plants look stressed or are dying, this may be the cause. Observe a full cycle and listen for hissing or excessive gurgling which indicates a leak or broken line. Check all emitters to ensure that they are working properly.

If your soil does not drain freely, waterlogged roots will quickly rot and kill the plant. This is easy to check. If the soil around the plant is soggy, this may be the issue. Sometimes this is the result of a leak in the irrigation system.Gophers may have eaten or damaged the roots. If the plant falls over or seems to be wobbly, a buck-toothed varmint may be the culprit. Although it will not bring your plant back to life, hunting down and killing the gopher can at least provide some consolation.

Sometimes, too, a plant may just die for no apparent reason. Go to the nursery and find a new plant to fill that empty spot.