At this time of the year a number of Iris reticulata hybrids are either emerging or in flower. Through our experience we have observed that these bulbs appear to prefer a well drained soil mix that contains a fair amount of grit and pebbles and a low percentage of humis. Soil needs to be neutral to slightly alkaline. Planting depth should be at least twice the length of the bulb. Shallow planting may result in bulbs splitting after flowering into smaller non flowering bulbs.  An annual application of a low nitrogen granular fertiliser should be enough to maintain their health. Having managed all these issues, the big ticket item is to ensure that soil around the bulbs is kept almost dry from early summer through to autumn. This can be achieved by growing the bulbs in pots or raised beds.