Ha, DrD has quicker fingers (and more knowledge) than I. Although since this is a cutting with extra meaning (from your son), I don't think I'd keep it in the water... I think it's time to move it to potting mix. Even with plants that root readily in water, those "water roots" are sometimes not very good at making the transition to "soil roots." But your cutting has started waking up and putting out roots, so I think it should root readily in potting mix now... ?
