Answer: In general, the lower leaves of a plant are the first to die as a plant ages. If there is a nitrogen or moisture deficiency, lower leaves send their reserves to the leaves higher up the plant. What you describe leads me to believe your geranium needs repotting, some fertilizer, or a more regular watering schedule. Perhaps it's just old, in which case you can take 3-4" cuttings from the vigorously growing shoot tips, root them in water, and transplant them to fresh potting soil.
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