My favorite tools are a
long-bladed, short-handled spade and two very large Phillips-head screwdrivers. Here in the US, the spade I'm using is commonly called a "Trenching Spade", but the linked terrierman (UK) page shows it as a "Drain Spade". These spades let you dig deeply with less effort and don't require that you lift a large spadeful of soil as you work. It's about all I ever use anymore. Sometimes, bargain tool outlets will have very inexpensive, large screwdrivers for sale. You want screwdrivers with shafts which are at least 6 mm in diameter with blades about 8" long. I recommend Phillips-head screwdrivers because they don't have sharp edges, but any screwdriver will work, as will a 14" tent stake or something similar.
In your confined area, (is the planting strip really only 10 inches wide, or are there 10 inches between the center or edge of the clump and the sides?) you'll probably have to use the spade to cut straight down on the sides of the clump near the concrete. You can angle the spade out a little as you work around to the area between clumps, (so you're digging more under the clump than straight down) but still try to stay about 6 or 7 inches from the edge of the clump in order to retain a good amount of root on the plant you're digging. Once you've made fairly deep cuts completely around the root ball, you'll have to get on either side of the clump and start to pry it upward as you work your spade further under the clump. It will be hard to do this and not compress the soil too much between the clump you're digging and the clump next to it, but try to keep it in mind as you work. One way to do this is to use the spade at a low angle and push the blade deep under the clump, and
lift the handle instead of pushing downward to pry it up.
Once the clump is broken loose, and while it's still in the hole, use the screwdrivers to pry into open spaces between the fans/crowns and the roots as well, separating as much soil as possible away from the roots, and separating the crowns from each other. Start by working the two screwdrivers together into an open space between some crowns and gently tease/pry apart. When you get it whittled down to a reasonable size, you can haul it out of the hole and onto a sheet of cardboard or a drop cloth while you continue to work on getting the crowns to separate. Always look for natural separations between the crowns and as you work, be aware of places where the crowns appear to be loose and come apart more easily. Water helps the process along, but may make more of a mess than you're willing to deal with. If you have a large bucket of water, you can dip the clump in there and it will make your work much easier. Always work and pry
between the crowns. If you try to grasp daylily fans at their bases to twist and work them apart, you're almost guaranteed to snap one of them off. I've done it, many times, even when I'm being careful. A daylily crown with a snapped-off fan will re-grow, but it will be set-back considerably.
