Did you have it indoors over the winter? The only one I brought inside to winter over this year is Blue Eyed Susan. It has some green leaves that stayed on thru the winter, even with me forgetting to water it regularly, and started to send out new growth in early April.
P. Incense was one that did not like being in my house, always ended up a brown vine with three or four leaves by spring and would not send out new growth until sometime in May....maybe give it a bit more more time or take it out of the pot and see if it has healthy roots, refresh the soil, place outside in a lightly shaded spot during the day ( you are a few zones warmer than me) to see if that will get it going...
