I planted several Eugenia myrtifolia 'Monterey Bay' in February. My goal is to prune them into a 15' formal hedge. When do I start pruning so that they will fill in up to the my desired height of 15 feet?
You will want to prune to your desired height, and keep it there with occasional prunings. This is the most common method. You can prune at several times per year, but it is best when the temperatures are mild.
Here are some articles that will help:
Our Eugenia plants (planted in the ground for more than a year now) have been dropping leaves and do not seem to be growing more. We live in the tropics so I'm not sure why and what can be done about it. It has been raining a lot though the past few months. Thank you.
They need acidic soil, so you may need to test the soil pH. They also need fertilization in spring and consistent water. I suggest removing the dead wood. While you are doing that, inspect the leaves for pests such as psyllids and scale. The browning leaves also could be a result of too much water if the soil is not well drained. Check to see if rainwater is pooling under the plants. If so, amend the soil around the plants with compost.
winter? I planted these in the ground outside before I knew they where not recommended for my zone
Your best bet is to plant them in containers, and bring them indoors or to a non-freezing area like a garage, for the winter. Just covering them in winter probably won't protect them enough. They cannot tolerate temperatures below 25 degrees F.