□
[□]
□?
Iris leaf spot is a common disease caused by the fungus , Mycosphaerella macrospora ( formerly Didymellina macrospora ) . Because you want your new shrubs to become established before the onset of hot weather , set out either bare-root or potted plants in spring as soon as the soil can be worked ; do not be afraid to plant early in the season , as even a plant that is beginning to leaf out can tolerate temperatures as cold as 19 F. They've also been seen in St. Paul , Stillwater , Hastings , Rochester and Winona , according to Doree Maser of the Minnesota Department of Agriculture . There are several iris diseases with similar symptoms that can occur when iris borer is absent , including bacterial soft rot , iris scorch ( probably caused by a phytoplasma ) , and fungal leaf spot ( Didymellina macrospora ) . The ability to accurately detect changes in topography will be especially useful for studying geomorphic processes , such as progressive sedimentation or trenching of alluvial fans , broad floodplain sedimentation patterns and delta exten-sion , formation and movement of large dune fields , and large-scale development of gullies - - e.g ., the type rapidly forming in steep , intensively cultivated terrains in Asia , Africa , and South America . Aluminum sulfate is not recommended as high rates of this compound can be toxic to roots .