Last week I dug up Iris rhizomes that had spread on the floor of what we call the old dog kennel. I have no idea how the first ever iris got into the dog kennel, maybe a seed had been carried by the wind, but when I tackled the kennel floor to try to clear it of weeds, I found that the iris had spread all over. It turns out that the rhizomes are really shallow, barely a few centimetres below the surface of the soil, which makes them really easy to re-plant. There are plenty o