Some plants will reward me with abundant blooms with very little water. Rosa mutablibis is a good example of this. From late March or early April it is full of flower, these continue to a lesser extent for most of the summer. Later when the cooler weather arrives they are covered with blooms again usually until Christmas.
This year I didn’t begin to irrigate until late June (more about this in my end of month view on the 30th July). I noticed that one end of the hedge was beginning to flower again and put the difference down to the fact that one end was receiving more light than the other; always at the beginning of the season one end of the hedge starts blooming before the rest. When I came back from Prague it was much more marked; there was a real cut-off point; up to one side of a line the roses were in full flower again to the other side not one flower!
Why, I wondered? Then I realised that the point where the flowers stopped was directly in line with where the end of one of the vegetable beds was. The light dawned! – The vegetables are irrigated and this bed has been watered since April. Although I use porous hose for the vegetables and imagined that all the water was only going to the roots of the plants in this bed; some water was seeping down through the soil and spreading to the roses; so very little water was making all that difference.
Rosa mutabilis is also interesting as the flower opens pale peach colour, then changes to pink, then darkens to crimson. This is largely dependent on temperature. The higher the temperature, the faster the change takes place.