Question: Why would several of my shrubs in a row die when those on either side of them are doing fine?
Answer: There are several possible causes. Be sure all of the plants are receiving the same amount of water. Sometimes shrubs grow large enough to block sprinkler heads. Either install a riser extender or trim the shrubs beneath the existing heads. It's also possible that cotton root rot is involved. It's a soil-borne fungus that moves slowly down a row. Many of our shrubs are susceptible. The problem also can be caused by nematodes. They're microscopic soil-borne worms that sting the roots of susceptible plants, sucking life from them. One plant will crop up with them, then it will spread to the two adjacent plants. You generally will see knots on the roots of nematode-infected plants. Boxwood, gardenias and figs are common victims.