Sounds very much like Clematis wilt, check the link below for more information.

Here is a link that might be useful: Clematis wilt

Kimmsr,

Thank you for the link after reading I feel it might be clemetis wilt. I will google search and look for more info.

Thank you so much for the help.

In general, clematis go dormant for the winter -- that is, the growth browns out and dies to the ground. So yours may have remained green because of the warmer "climate" indoors.

I suspect the plant is fine -- that is, unless it has a root problem. For now, squish the aphids and keep the potting mix barely moist.

So, wherever it is that you live in the United States, if you have a suitable site in the garden, plant it outdoors come spring.

Clematis wilt typically occurs during spring or later, when one or more stems suddenly die back. And although the cause has been debated, it is commonly due to the gardener (or a pet) inadvertently breaking the stem. For the most part, you can avoid such wilt by planting the crown of the clematis 3 to 4 inches below the soil surface.

I'm curious too as to why you brought the clematis indoors. Normally, indoor temperatures and low humidity, lighting, aren't ideal for hardy deciduous plants. This is a mild Zone 8b, but clematis of several types have been fine in the ground, also seedlings in pots, cuttings in pots, this winter and they've all had temperatures into the teens - growth buds are swelling and appear undamaged.

Are you in a harsh winter climate or can you gradually ease this plant back outside?

It is sweet autum clemetis and I grew it from seed last summer and it was in pot all summer and was only 2 feet big. It had only one stem. It was my first clemetis so I thought it might die in harsh winter so I brought it inside and kept nearby window. btw I am in zone 5. It did really good and was growing well. Only recently all the leaves withered but it is not black as suggested for wilt. Then the top stem began to brown and worked it towards down. now 2-3 new shoots came from soil. But one shoot died from top upto the first node and the half stem is still green and looks ok. The rest of the two new shoots also looks ok.

I hope that it would survive but not sure. At present I can't keep it outside since the temp is still around 30 F. If it does ok I would plant it outside in spring.

Do I repot it or just leave it as it is?