3-yr. old plant; part-shade; watered 3 times a week
It may need some fertilizer. Also check it for insect pests. Here is more:
https://www.gardeningknowhow.com/ornamental/flowers/gardenia/no-flowers-on-gardenia.htm
I planted it about 30 yrs ago and it bloom every yr but it had gotten so big and out of control that I cut down to about 2 ft. It doesn't seem to be sprouting any greenery. It also has some white on the big limbs. Will it ever bloom again and what would I need to do to get healthy again.
Cutting too much of the plant at one time could stress your plant, causing it to not set as many flower buds and even drop its leaves. Pruning in the middle of hot Texas temperatures from June-September, when daily temperatures can hit 100+, may cause shock. The plant may restart growth once environmental conditions improve in October or may even wait until spring 2024. Do not fertilize it now but maintain the soil mulched with 3-4” of organic mulch past where the drip line used to be, as roots will extend that far. Maintain the soil evenly moist during the summer, not letting it get bone dry nor soggy wet.
What should I spray my gardenia with to kill mite.
My preference is neem oil, but there are several things that you could use. These articles will help:
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/azadirachtin-vs-neem-oil.htm
https://www.gardeningknowhow.com/plant-problems/pests/insects
https://www.gardeningknowhow.com/plant-problems/pests/pesticides
Is it o.k. to leave potted gardenia's outside for the winter?
Since you are in zone 9, they should be fine, however, I would move them to a protected area out of the chilly winds. If you get an unexpected cold snap, you can cover them with blankets or cardboard boxes. Here is more:
https://www.gardeningknowhow.com/ornamental/flowers/gardenia/gardenia-winter-care-tips.htm
I was cleaning spent flowers from my frost proof gardenia plants and found the branches covered in what looks like tiny snails. They are white and are hard. The plants bloomed twice this year and were rally healthy looking. I have them in large pots on my patio. About 50% of the leaves on the most infested plant are yellow which has not happened in the five years that I have had the plants. Checked online and no source mentioned snails. I am very familiar with all garden and indoor pests and have not seen these creatures on any other plants. Do you know what they are, how destructive they are, and how to get rid of them. Unfortunately, I can't upload a photo. I might be able to text a photo.
It sounds like it would have to be a type of scale, possibly the Japanese wax scale, which has a white, waxy coating and is common on gardenias. Here is more:
https://projects.ncsu.edu/project/pestmngt3/AG189/html/Japanese_Wax_Scale.HTML
https://hgic.clemson.edu/factsheet/gardenia-insects-related-pests/
The size of a gardenia's root system can vary depending on several factors, including the age of the plant, the specific gardenia variety, and the growing conditions. Generally, gardenias have a fibrous and shallow root system, which means that their roots tend to spread out horizontally near the surface rather than growing deep into the ground.
When planting a gardenia, it's important to provide adequate space for its roots to spread. A mature gardenia plant can have a root spread of 3 to 6 feet (0.9 to 1.8 meters) or more. The roots typically extend beyond the drip line of the plant, which is the area beneath the outermost branches of the shrub.
To encourage healthy root development and growth, it's essential to provide well-drained soil, regular watering, and appropriate fertilization. Gardenias prefer slightly acidic soil conditions, so maintaining the right soil pH is also important for their root health and overall well-being. Proper care of the root system is crucial to the overall health and vitality of the gardenia plant.
https://www.gardeningknowhow.com/ornamental/flowers/gardenia
Max sea acid fertilizer. Could the heavy rains for last winter have affected the blooms?
I suspect that the soil is too acidic, not allowing proper intake of phosphorus and potassium. This could affect blooming. Acidic fertilizers should be applied quarterly, or every three or four months. Regular fertilizers should be used in between. Testing your soils can confirm.
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/testing-moisture-in-plants.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/testing-soil.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/soil-ph-plants.htm
https://www.gardeningknowhow.com/ornamental/flowers/gardenia