What's the name of the plant in verges with green blade foliage with white, purple and yellow flower spikes

Trying to put a name to a very common plant used by councils for verge plantings. They have green blade like foliage and flower spikes with white,purple and I think yellow on them. Mine flowered in November but saw one yesterday in Petersham still flowering. As I said they are prolific and hardy but I can,t find a name. As I am an old fogey I haven't worked out how to convert a photo into JPEG from my iPad. That would make things easier !!!!!!! P.s. It is not a liriope as I have those as well. Cheers. Keith