All plants, even terrestrial ones, can get their nutrients through the leaves. You don't need to feed any aquatic plant through the roots. (Yes, I do think there are a very few unusual aquatic plants that feed only from the roots, but they are far from the norm.) We always see sword plants, crypts, and other heavily rooted plants called "root feeders", but all plants can take in nutrients from the roots, and all plants can take in nutrients from the leaves.
I once had a few sword plants in a 29 gallon tank, in inert substrate, with only EI fertilizing. Within a couple of months they had totally filled the tank, growing very fast. And, sword plants are one of those that people swear need root feeding. They don't!