My vine is about 5 foot tall. It is in a container. It gets full sun. The blooms come out but do not open fully. I don’t know why I need your help.
It looks like it has opened, and finished its cycle by being pollinated. They usually won't last more than a day or so, anyway.
If it is not pollinated, it will close back up during the day to open at night, since these are a night blooming species due to the type of insects that pollinate this flower.
Just make sure to keep the soil nutrients at a moderate level. Too much nutrients will halt flowering for this plant. In fact, they prefer poor soils to nutrient rich soils. Alternatively, just a boost of phosphorus, potassium, and sulfur can help with flowering.
Here is an article that will help you to care for this plant:
https://www.gardeningknowhow.com/ornamental/vines/moonflower/growing-moonflowers.htm
Moon flower or datura? It’s not a vine it’s a plant . Will grow very large. Plants seem to open in the evening or night. Sometimes open during day. Your article says the toxins ones smell bad. These don’t. They smell lovely. Will they poison the other plants around them? The plants around them are big concern! I’m already keeping people and pets out. Like sunflowers and black walnut trees can make soil bad for other plants? Are they toxic in the variety I have to touch or dogs to be around?
Yours sounds like it is the Moonflower Datura and it is a bushy plant. All parts of the plant are extremely toxic although I didn't find anything that said the toxins migrated in the soil. The article below is rather sobering if you have inquisitive kids.
https://www.uaex.uada.edu/yard-garden/in-the-garden/reference-desk/vines/moonflower.aspx
https://hort.extension.wisc.edu/articles/datura/
https://plants.ces.ncsu.edu/plants/ipomoea-alba/
I just read your article about harvesting moonflower seeds from my plants (https://www.gardeningknowhow.com/ornamental/vines/moonflower/moonflower-seed-harvesting.htm) and I understand that I should wait until the seedpods turn brown in color. I have been doing this incorrectly (and having no success with the seeds), because I have never left them on the vine long enough for them to turn brown, due to the increasingly wet, cold Mid Atlantic Autumn weather where I live (Long Island, NY). At what point is it safe for me to take cuttings of the vines with the seedpods attached and bring them inside to turn brown and fully dry? Or must the seedpods stay attached to the living vine until it has turned brown, no matter what the weather does?
It's best to leave them attached to the living vine until they turn brown, regardless of weather.
https://www.uaex.uada.edu/yard-garden/in-the-garden/reference-desk/vines/moonflower.aspx
year in a row this has happened. What’s my issue?.
This could be due to three main factors. Too little light, too much water, or too little nutrients.
Potting them up to larger pots with substantial soil will likely mitigate the issue.
https://www.gardeningknowhow.com/ornamental/vines/moonflower/growing-moonflowers.htm