Hi plaz, Not an expert here, but in my experience( I live in FL), In my experience with my gardenia, especially when the plant is only three months planted I would water it every other day. My guess is you are not watering it enough, once a week for a plant that is not establish yet and blooming needs more water. Since you are in zone 10 I'm guessing it is also hot where you are. I was always of the assumption that flowering plants need more water. Since you checked for pests, try this and see if it makes a difference. I water mine every other day and the plant is full of buds right now. Good Luck! Here's an article from University of Florida on Gardenias The whole article is below. Irrigation "Watering during dry periods is necessary for healthy gardenias. Moist soil is essential for successful gardenias. Watering is important because it largely controls the number of flower buds that remain on a plant to maturity. If water stress occurs in a heavily budded plant, many buds will fall before opening. Therefore, while the plant is in bud, large variations in soil moisture should be avoided. Use mulch and avoid cultivation around the base of the plant to help maintain adequate moisture" Here is a link that might be useful: Gardenias (UF)

I thank all of you for your help. This morning I took out the problem succulents and brushed off the dirt as best they would allow. Could you help me identify what is root rot, how do the roots look if they're healthy or if they are rotted? The smaller succulents at the bottom all have relatively shorter roots, and the soil around them was dry. The bigger succulent in the top photo had tightly compact soil around its roots that I found almost impossible to break off without tearing out all its roots with it! It was completely bone dry, I think that is what you all meant by hydrophobic; it was so tight and dry no water was getting through. In the photo you can see some water droplets, where I sprayed lightly with a spray bottle onto the dry soil. All the arrangements you see above are temporary, my main goal is to prepare them all for the nice, larger planter I am creating. I live outside of the US, so I am afraid any brand names or chain stores you mention won't be of any use to me, 'tis why I am trying to make with the best I have, or find similar products by other names. I do realize I have regular potting soil, I went out and got some grit, like small pebbles and clean sand, witch which I plan to mix it altogether like suggested.

Likely just needed more water. BUT also check if the soil is staying too soggy and air starving the roots! For instance, if sitting in a saucer, make sure it doesn't stay in standing water for more than a day or two. This summer I had a large Brug tub on the lawn, whose hefty root growth plugged the container. It was wilting and watering didn't help. I put the tub on its side and used an electric drill to open the drainage holes. This fixed the problem within a couple days. Take home lesson is to put Brugs in planters elevated with feet or if flat bottomed place them on a hard patio surface or piece of flat tile or plastic. Otherwise ground soil contact with the planter bottom can encourage roots to creep out seeking water, and plug the planter.

Even w/out a pic, blackening on a plant often means rot, which is often fatal, so pls. don't get your hopes up.