THOSE great showy flags, bearded irises, should be divided when they become overcrowded, which could be every three or four years. Dig them up as soon as they finish flowering and cut the rhizomes into pieces with at least one sprout each. Throw out any woody or pest-eaten parts. Cut back the leaves by about half and replant 24 inches apart in soil that has been refreshed with compost. Put them in a sunny, open position and leave the tops of the rhizomes exposed so that they can get a good baking.
Greenhouses are really hotting up now and some sort of shading or light-filtering device is essential to stop leaf-scorch and excessive drying. The proprietary, milky, glass paint seems not to be available now but apparently a (messy) substitute is a light solution of lime-and-water brushed onto the inside of, the glass. Last year, in this greenhouse, retired lace curtains fitted to the south-facing roof slope made an effective sun-filter. Any very loosely woven material (onion sacking, for instance) should do the trick.