Answer: It sounds like scorch, a new iris disorder that's running rampant in the Midwest, says Tom Abrego of Chehalem Gardens, growers of 35 varieties of spuria irises in Newberg, Oregon. The symptoms are browning of the leaves followed by rapid decline of the clump and eventual death. Ironically, scorch seems to affect the healthiest irises first, says Abrego. No one's sure what causes scorch. Your best bet is to immediately remove and destroy affected plants. Luckily, spuria irises are tough plantsthat require less care than bearded and Siberian irises. The varieties Belise, Royal Belise and Lenkoran are the most carefree, says Abrego. To keep your spurias healthy, water well in spring, but don't water after they finish blooming. Most spuriasgo dormant in summer and watering can cause crown rot. Lightly fertilize in May with 10 10 10 (one cup per a 100 square foot bed), keep the area weed free and cut back the leaves to six inches tall in late fall.
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