Especially for Gardenias. Thank you.
Typically, I would recommend systemics for licenced applicators, only. Many can be harsh, and carry legal consequences, if used incorrectly.
I don't, normally, recommend specific products, but in this case I will. Since choosing a safe product is paramount in this situation, I see it necessary to recommend a safe way to use a systemic control.
SNS 209 from Sierra Natural Science is what I use. It is organic, and works well without being a risk to the environment or other plants in the area.
Here are some articles that will help you with the care of Gardenia and Hydrangea:
https://www.gardeningknowhow.com/ornamental/flowers/gardenia
https://www.gardeningknowhow.com/ornamental/vines/climbing-hydrangea
Hi. Your website has been pretty helpful, but I have a black thumb and I still don’t understand where to do this. Plus all of the Internet drawings are hard to comprehend. I have been deadheading the gardenias right below the leaves that the bud comes out of. I will include a picture. I don’t know if that’s right and I feel like I need some kind of picture to tell me if I’m doing it right because it doesn’t make sense. I’m attaching a picture and my nail is about where I remove the spent blossom. Before, I just took off the dead flower and left the “star shape” it came from.
The article is saying to cut it off below the flower but down to the first leaves so you don't leave a bare stem. Just cut right above the leaves. Here is more:
https://www.gardeningknowhow.com/ornamental/flowers/gardenia/removing-spent-blooms-on-gardenia.htm
I received plant as a gift and want to place it outside in a decorative pot
As long as your container has plenty of drainage holes, then it is not necessary. It can be helpful, and I do so myself, but it isn't necessary for the plant's survival.
This article will help:
https://www.gardeningknowhow.com/ornamental/flowers/gardenia/gardenia-plant.htm
If you choose to grow it indoors, instead, then this article will help:
https://www.gardeningknowhow.com/ornamental/flowers/gardenia/growing-gardenias-indoors.htm
I just planted gardenia plants in pots. I learned the soil needs to be acidic. what is the PH range for these plants. How often should I water the plants?
Maintain the soil acidic with a pH below 7 although they will tolerate some alkalinity too. The roots are shallow so water when the top few inches feel dry. Use a well draining, ericaceous potting mix.
How deep should it be planted?
Both. If you aim for morning sun until 11am-12pm and shade in the afternoon/evening, you will be fine. Shade is more critical in areas with hot summers.
Plant it as deep as it was in the container.
I have never seen that one before, but it looks like a species of mother caterpillar. This article will help you with caterpillar control:
https://www.gardeningknowhow.com/plant-problems/pests/insects/prevent-caterpillars.htm
This collection of articles will help you with the care of Gardenias:
https://www.gardeningknowhow.com/ornamental/flowers/gardenia
They were outside for the Summer and must be moved inside due to my very cold climate.
Spray the leaves with Neem oil before you bring the pot in. I like to repot my plants before I bring them inside.
https://www.gardeningknowhow.com/ornamental/flowers/gardenia/gardenia-pests.htm