Last fall I cut back my 16" pot of black and blue to about 4 inches and stuck it in a black bag in a 45 degree basement for winter. Over winter, despite the darkness and cold, white shoots slowly grew out of the base of the main stem. By the time I brought the pot out of the basement on April 1st the plant had several weak, white shoots, up to 3-4 inches tall. Because the shoots were pretty weak I pulled them off to let the plant start fresh. Naturally, I assumed the plant would quickly start growing again once it got into the sun and warmth(also spent a couple weeks in the warm house because of a bad cold stretch). However, it's May 12th and the ONLY growth is a little shoot very slowly emerging from a node 3 inches up on the stem. I don't see a lot of potential with that shoot. The plant is obviously alive(grew during winter and all of the stem is obviously green even without having to scrape the outer skin to expose the inside) and I was expecting this thing to take off pretty quickly from the base of the stem or roots. Over the last week our weather has been mostly sunny with highs in the 70s, 80s, and even low 90s, but there is still no real growth. What's the deal?