My Rojo Philodendron Leaves Stay Curled And Don\’t Unfurl Very Quickly.
It is winter, plant is indoors and gets bright indirect light from a southern exposure.
Certified GKH Gardening Expert
Unfortunately, your photo did not come through. There are several things that can cause this.
The first thing to consider will be temperature. They tend to grow faster with temperatures that remain in the 70's or above.(they can tolerate down to about 65 if it is not too often) If it is a little chilly, it will take much longer to grow.
The next thing to consider will be humidity. If it is not humid enough, then the plants will not grow properly. A humidifier will help with this.
Last, is lack of nutrients. These can be considered heavier feeding plants, so you will need to feed, at least, once per year.
Here is an article that will help you to care for them: https://www.gardeningknowhow.com/houseplants/philodendron/congo-rojo-philodendron.htm