My Troublesome Mandevilla

I just moved to Clarksville, TN at the end of February.  The highs during the day were awesome so I put my plant outside.  The lows were not supposed to get below freezing.  It was a bit windy and the sun was pretty bright.  After a couple days all of the new growth it had formed while being inside had died off.  I either killed it, made it go dormant, or it's working under the soil on producing something.  It is now the 27th and still nothing.  I even cut the plant itself down to just the main stalks about 3 inches above the dirt to help focus energy in the stalks.  I brought it back inside to see if it will give me something.  I have some sprouts popping up in the dirt, 2 different kinds.  I'm thinking I picked up some weed or grass since the pot was on a grassy area and people have been mowing their lawns.  But perhaps the mandevilla decied to produce a new stalk???  I'm going to let them grow and see.  I also added a little bit of dirt to the pot because it looked like the roots were getting near the top.