Q.Gardenia
The blossoms are dry and hard, not falling off. The leaves are yellow. What should I do?

Gardenia are a finicky plant.
If the flowers have faded, you should dead head those from the plant.
Yellowing leaves can be an indication of watering issues, disease, pests or nutrition.
These articles will help you pinpoint the cause.
https://www.gardeningknowhow.com/ornamental/flowers/gardenia/gardenia-plant.htm
https://www.gardeningknowhow.com/edible/helping-a-gardenia-bush-with-yellow-leaves.htm
https://www.gardeningknowhow.com/ornamental/flowers/gardenia/common-gardenia-diseases.htm
https://www.gardeningknowhow.com/ornamental/flowers/gardenia/gardenia-pests.htm