Hello and thank you for contacting us. To determine if your plant needs a larger pot, have someone tilt the pot so you can inspect the bottom. If the roots are visible in the drainage holes, it is time to upsize the pot. Be sure the pot is raised above the drainage dish so that it does not sit in any excess water.

From your photos, it appears your gardenia has scale insects. These small ins---ects have sucking/piercing mouthparts and form a hard shell as a protective coating on stems or other plant parts. The insects can weaken the plant and lead to other problems. Here is some monitoring information:

"Inspect twigs and tissues during the dormant season for scale insects. Pay attention to sickly plants and those with low vigor. The scale crawler stage is most susceptible to chemical control measures. Monitor the movement of newly hatched crawlers by wrapping a piece of sticky tape around an infested branch with the sticky side out. The crawlers are very small and best observed with a 10X magnifying glass. Check beneath scale for live females or eggs, or for predator mites or parasitoid wasp grubs. Fluff beneath scale could indicate parasitoid activity or that the eggs have hatched. Holes in a scale insect covering indicate that parasitoids have emerged."

"Home landscape products are those pesticides that can be purchased at local retail stores and can be used without a pesticide license. These products are listed by active ingredient [not by brand or product name]; products based on the same active ingredient may be comparable and effective. Restricted-use products may be used only by applicators with the appropriate pesticide license. For all products, the applicator must review the pesticide label as some products may negatively impact some species of ornamental plants and some products may only be applied to specific areas within the home landscape. In the case of any discrepancy between these recommendations and the product label, ALWAYS follow the product label. Remember pollinators, such as honeybees, are often susceptible to insecticide products."

I am attaching a list of chemical controls approved for home use. Please note that some may not be appropriate for indoor use. Please read and follow all label instructions carefully!