If you're new to dealing in an infestation of succulent pests, you can also learn about how to treat them. Scales are small brown or gray oval-shaped pests typically found on the leaves and stems of your succulents. In fact, garden pests have been devastating my aeoniums in the past year. The flowers appear usually in spring or summer, and can remain for the majority of the growing year. Root rot will occur when the soil retains too much moisture. Therefore, the soil in which you plant cacti must allow for adequate drainage. Cacti look good when placed on a table.