Hi Pat, >>I don't expect this plant will ever now catch up to the others, but it will be interesting to see what happens to it in the long run.<< You are right if you leave things as they are. The retarded root system will never completely catch up with the others. How would you like to have that plant actually bypass the rest? First, pluck up your courage and dig up the affected plant. Do it gently so as not to lose any more root. You will find a smallish root ball. Now dig a trench six or eight inches high and line it with compost, peat moss or a mixture of both. It might be a good idea to mix in some high phosphorous fertilizer such as 5-10-10 or 10-20-20. Put the length of the stem along the length of the trench and firm the soil around it, leaving only the growth tip above ground. Don't worry about the growth tip being at an angle. it will straighten up on its own shortly. Water the plant in well and keep it damp but not soggy. In a few weeks, roots will form along the buried stem and that plant should eventually surpass the others in the garden, I have tried this with "leggy" transplants and it works like a charm. You will be amazed at size of the root ball you eventually dig up in the Fall! Good gardening, Chuck Wyatt