makes all the difference.
Shifting the Shasta Daisies in the flagpole garden, which meant hauling out a solid 20 square feet of matted plants, I was happy to have my belief confirmed. A digging knife, of the heavy duty sort with a wickedly sharp serrated edge on one side and a straight blade on the other, is indispensable for that sort of perennial plant division. A good digging knife has to be made with nearly the thickness of a shovel, with a full tang, a good handle, and capable of holding an edge; the amount of force one wants to be able to use is considerable.
Shasta daisies form a mat of surface roots about the width of a finger. Like most roots they have a fair bit of ‘give’ in them, so cutting through them from directly above takes quite a bit of force, even with a sharp shovel. Remember that the ground below them also compresses, enhancing that give. Now, you can get through them with a shovel; but the amount of force is considerable. Furthermore, the effective use of the shovel (or even a properly sharpened edger) means morrising about in the garden somewhat. Not what you want to be doing if the Shastas are encroaching on asters, poppies, and irises that do not want to be damaged. With the knife however, one can stab through the mat and cut back towards one very effectively, sectioning the mat into pieces. Then insert the shovel and pry out the section. Voila. The other plants are undisturbed, the Shastas are out. Now….I just have to finish reworking the edges and replant the blessed things….. The easy part is done.
The knife I use came from Lee Valley and is about as close to indestructible as one can get, highly recommended.