also note when you cut it it typically splits at the cut into 2 branches.... It is generally best to do the cutting down low about 2-3 inches from gravel and let it split for a bit and grow some length toward the top and then remove the new splits as two separate pieces and replant them and discard the original base. Once you have enough for what you want you tend to find yourself snipping it off and throwing out the bottoms right away though. Now I tend to just cut off around the top after it grows across for a bit just below a couple new roots that come out and then plant that part (just the roots) and throw out the rest.
Also pressing the plant into the gravel will cause it to rot. Only the roots go good in the gravel. It is best to weight it down so that the stalk is above the gravel and a few roots are in the gravel to keep it held in place for awhile until more roots can anchor themselves. It is possible to trim carefully down toward the bottom to get a multi-strand growth but this takes some patience. You basically keep trimming somewhat low to get main strand to split into 2-3 strands and then trim those to split them after they fatten up some etc until you get a larger amount growing. As they get too big chop them down low and let them grow back.