I went to my local garden center a couple of weeks ago and they had a large, beautiful philodendron Selloum on sale. I couldn't pass up its extremely tropical looking leaves, it was just so pretty. When I got it home I realized that it was extremely root bound, so I repotted it into a larger pot. I had to cut away the old nursery pot, three of us couldn't get it out of there. Now I have leaves turning yellow. I already cut off 2 but now 4 more have turned yellow. I watered the pot with Plant Starter, which is similar to Super Thrive, to help reduce stress on the plant. I also have it sitting in full sun. Am I doing something wrong? I am not familiar with this type of plant and I am not sure on proper care. I have read so many things online that contradict each other. I.e. One says full sun, another shade, yet a third says part sun/shade. Oh, I also gave it regular Miracle Gro houseplant spike fertilizer, I didn't know what else to give it. Any suggestions?
Can you post some pictures? There are a few possibilities and pictures might help figure out which thing is responsible. One is that it's just a bit of stress from repotting--if you had to be a bit rough with the roots when you transplanted it that could cause some yellowing (might be best to put it somewhere a little shadier until it gets settled in). Too much water is another possibility. Or maybe sunburn...I've never grown this so can't tell you how much sun it can take, but even if it can handle full sun, if the nursery you bought it from had it indoors or somewhere relatively shady and then you plopped it right into full sun it could get sunburned (need to adjust it gradually to the higher amount of sun). Fertilizer burn is another possibility--it's best not to fertilize right after transplanting, give the roots a chance to recover first. Stuff like your Plant Starter/Super Thrive is fine, but I'd wait a few weeks before fertilizing.
I have 6 big ones in my garden. They thrive with no care at all, but they are in shifting shade of a big oak tree. I think you need to put that baby in the shade and see if it recovers.
Some plants, like my orchids for instance, actually make their leaves a lighter color if they are in too much sun. Move them to the shade, they darken down again. Don't know if the P. Selloums will do this but they might.
The name is actually Philodendron bipinnatifidum and generally they only look good in full sun in a tropical environment, with constant very high humidity. Otherwise, as others have said, bright light but shade. They also don't have a high fertiliser requirement and too much can cause burn. Giving it a good flush with water and some shade should see new leaves come up. The old leaves should fall away and will only be a temporary set back. They're quite a tough plant but can look pretty bad in the wrong conditions.
Thanks so much for the advice! Ecrane I will post pics tomorrow so you can see what I am talking about. I moved it to the shade today, so I will see if that helps. I will flush the plant with water tomorrow and dig out the fertilizer spikes.