Complex sentence: When potted, aloes become crowded with "pups" growing from the sides of the "mother plant", they should be divided and repotted to allow room for further growth and help prevent pest infestations.
Split into simpler sentences: When potted, aloes can become crowded with "pups" growing from the sides of the "mother plant". Plants that have become crowded should be divided and repotted to allow room for further growth and help prevent pest infestations.