Good morning, and thank you for your question. The answer I found for what you describe may be precise or not, but the last sentence of the paragraph holds the key: dig up and discard the lambs ear and don't plant another one in the same area. That advice would hold true for a number of plant problems. Lamb's ear, planted in another area, will reappear in spring and spread, so getting a new plant is the solution to this problem.

Please read this from a gardening website - please call on us for any other gardening questions - Jeanne

Lambs Ear Plants Stunted, Yellowed; Root Lesions - Nematodes
Nematodes are not insects, but slender, unsegmented roundworms. Most are microscopic-sized soil dwellers. They have piercing-sucking mouthparts and feed on cell contents. Several kinds of nematodes occasionally attack leaves or roots of lamb's ears. Infested plants look sickly, wilted or stunted, with yellowed or bronzed leaves. They decline slowly and die. The roots are poorly developed, have little knots in them, and may be partially decayed. Control the pests by digging up and discarding severely damaged plants, and by adding lots of compost or moldy, semi-decomposed leaves if they are available, to the soil to encourage beneficial fungi that attack nematodes. If the pests are a recurrent problem, do not plant lamb's ears in that location.