Probably the most important part of the plant is that which you don’t actually see — its roots. Roots perform all sorts of functions for its plant (see Plant Roots 101), so it pays to not only do what you can to create a good environment for roots to become and stay healthy (see Happy Roots, Happy Plants), but to choose plants from the beginning that already have healthy roots. You don’t want to come home from the garden center with a carful of plants that have unhealthy roots, do you? Of course you don’t — so here are the steps to take and what to look for before you purchase.
Look at the plant in its nursery pot. Does it have roots coming out of the bottom drainage hole? Are the roots visible on top of the soil in the pot, creating a circle? The plant may be root-bound, which means it’s grown too big for the pot it’s in. This creates all manner of growing problems, so best to avoid it from the get-go. Let’s move on to another, more healthy plant.
Remove the plant from its pot. Wait, you mean at the garden center? Yes, that’s what I mean. It’s okay, trust me — I don’t do this with every single plant I’m going to buy, just the ones that I may have a question about or want some extra reassurance for. Hold the container on its side and carefully slide the plant out of the pot. It should come out fairly easily, but it should not fall out without a little coaxing. If it seems stuck in the pot, it may be root-bound, and we’ve already established that we don’t want that.
Now inspect the roots. You should see roots that have a whitish or tan color, and look plump. Brown, shriveled, cracking roots simply will not do. Roots forming a tight circle at the base are root-bound; pass on these plants. Roots that are visible at the top near the base of the plant but not at the bottom of the soil may not be fully rooted. You’re looking for roots that look healthy and are growing throughout the potting soil, not just at the top.