Hi Colin, in my experience the Kerria is a suckering shrub with naturally bare lower stems. The only way you will obtain lower foliage is on the young stems before they gain height. It should send up many new shoots as it matures. My method of pruning is to remove a couple of the oldest stems every two years. You can certainly top the growths at the height required and that will induce new growths from the roots - if it is newly planted give it a couple of years to settle in. You can always plant something of a suitable height in the front to help hide the stems if you don't find them attractive; I like the clean green of the Kerria stems. As a suckering shrub sending out growths directly from the roots you can cut an established plant to the ground and it will regrow.