Hello, I have a small firestick version of pencil cactus, maybe 6 inches tall, in a pot of succulents that was given to me. The "sticks" coming up from the ground are withering at the bottom and die going upward. The pot seems to have regular potting soil in it, and I'm wondering if it's too wet? I am in Texas, USA, and this is on my front porch where it gets direct sunlight from early morning until close to noon, and then bright indirect light the rest of the day. Years ago, my husband worked in an office that had a (regular green) pencil cactus in the front lobby. It was at least 6 feet tall and had one single trunk and branches coming off from it in the shape of a deciduous tree, and it was so unusual that I just had to have one. I have been trying to grow one for years. Unfortunately, they're not easy to find and I have only been able to get my hands on one which I lost in a fire a couple years ago, so I'm eager to keep this one growing. I would be very grateful for some guidance on what to do. Thanks! PS: when I went outside to take a picture, I found a spider with web and then a bunch of teeny, tiny dots around some of the other plants. I have no experience with this, but I'm guessing spider mites? They look like the pictures I see online. These aren't on the firestick plant, though.