They will have a very specific care routine. They will thrive indoors if these conditions are met. This article will help you with their care:
https://www.gardeningknowhow.com/ornamental/vines/mandevilla/growing-mandevilla-indoors.htm
Can u break into 2 plants without killing?
Are you referring to the mandevilla vine? If so, here is information that may help.
https://www.gardeningknowhow.com/ornamental/vines/mandevilla/mandevilla-plant.htm
https://www.gardeningknowhow.com/ornamental/vines/mandevilla/growing-mandevilla-indoors.htm
https://www.gardeningknowhow.com/ornamental/vines/mandevilla/mandevilla-plant-tubers.htm
we live in townsville north queensland and it is a sub tropical inviroment, plant is potted and situated on verandah and is partly shaded, watered via a dripper system at odd times,have enclosed two photos, hope that you can give me advice and a reason for this.
It looks like infection from overwatering. You will need to treat with a fungicide, and make sure to only water when the soil is completely dry down to about 2 or 3 inches.
This can also be worsened by too much light. They should receive quite a bit of shade throughout the day, as well.
Here are some articles that will help:
https://www.gardeningknowhow.com/ornamental/vines/mandevilla/mandevilla-plant.htm
https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm
I brought six mandevilla plants indoors last winter. One died, the others are growing strongly, but no flowers. What is my next step?
This article will help you.
https://www.gardeningknowhow.com/ornamental/vines/mandevilla/getting-mandevilla-to-bloom.htm
My Mandevilla plants are covered with little yellow bugs that I cannot identify. Please help me to find out what they are and, most important, advise how to get rid of them. See the photo.
That's a large crop of aphids on your plant!
Wash away as many as you can with a spray of water, then treat with Neem Oil.
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
https://www.gardeningknowhow.com/plant-problems/pests/insects/homemade-aphid-control.htm
It is in a hanging basket, and is on the south side of the house.I'm wondering if it's getting too much sun? I feed it Miracle Grow every 3rd or 4th watering.
Yes, it may be getting too much sun. They don't like direct sun but rather filtered sun. Also check the plant for bugs. Check these care points and see if you are doing all of them:
https://www.gardeningknowhow.com/ornamental/vines/mandevilla/mandevilla-plant.htm
https://www.gardeningknowhow.com/ornamental/vines/mandevilla/mandevilla-plant.htm
I have it in the sun, in it's original pot with a trellis for it to grow on. The leaves are turning yellow. A few of the vines are dried at the end.
It could be due to watering, too much or too little, lack of fertilization, disease or insects. Here is information that covers all these points; you can see which one fits your situation. Also, since it is in its original pot, which may be small, you will need to water more as the moisture will evaporate quickly. It may need to move up to a larger container.
https://www.gardeningknowhow.com/ornamental/vines/mandevilla/yellow-leaves-on-mandevilla.htm