I have it in water & I did fertilize recently. It has a healthy amount of roots - I am wondering if I should cut some of them back? They don't look very good here...
That, actually, has the tell-tale markings of the Pothos plant. Though it isn't even closely related, they do have similar care.
With that being said- Growing them in water, unless you grow them hydroponically and with aeration (pumped air) will be a very slow process. They will grow faster in soil, but still usually pretty slow without very bright ambient light.
The only thing to do is make sure to care for the plant as it slowly matures. This means keeping the water fresh, and feeding a few drops of nutrients on the rare occasion. They aren't heavy feeders, though. Keep it warm and in bright but indirect light and it will continue to be healthy.
Alternatively, you can choose to plant it in soil. They will grow much faster, but will require constant care to keep them in check.
These articles will help: https://www.gardeningknowhow.com/houseplants/pothos/pothos-plant-care.htm
https://www.gardeningknowhow.com/houseplants/pothos/propagating-pothos.htm
I have a twenty year old Philodendron Monstera, split leaves (I think the identification is correct) It has always lived in my hall, partial sun, and is happy. But it has long, brown thin 'roots' that grow over the pot and creep along the carpet! Some are two/three feet long, and I cannot work out what their purpose is, and I have to loop them out of the way. Can I cut them off, or what is their purpose please? Many thanks
You can cut them off. They are air roots. Here's how:
https://www.gardeningknowhow.com/garden-how-to/info/trimming-air-roots-plants.htm
It is winter, plant is indoors and gets bright indirect light from a southern exposure.
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
Patio plant huge and occupying to much vertical and horizontal space; must remove OR, if I cut back few feet of the trunk (top it), will it sprout new growth ??
Here's an article that should help you:
https://www.gardeningknowhow.com/houseplants/philodendron/pruning-philodendron-plants.htm
You can top off the main growing stem just above where a side stem grows.
I have a philodendron (sp?) hanging in my sunroom....the room is heated in winter and cooled in summer....the plant keeps growing but leaf edges have turned yellow....not sure if it has disease, watering too much or too little....can you help....thank you.
Following the cultural care tips can prevent foliar problems. Compare the tips below with your plant's care. It could be over or under watering, too much or not enough light.
https://www.gardeningknowhow.com/houseplants/philodendron/caring-for-philodendrons.htm
https://www.gardeningknowhow.com/houseplants/philodendron/brown-philodendron-leaves.htm
leaves. Should I cut the roots down?
That is a very difficult life for a plant, even those tolerant of it. It will be expected to see a drastically shortened lifespan.
I would, first, try to transplant into soil to give it a few more years, before tossing it out.
This article will help you to care for them:
https://www.gardeningknowhow.com/houseplants/philodendron/caring-for-philodendrons.htm
My philodendron has only 2 leaves at the top of a single 18 inch long stem; if I cut the stem down, will the plant grow back ?? The plant is 50 years old, I would use the top part, that I have cut off, to propagate a new plant !!
The cutting might make it, but it could kill both of them, due to the age of the plant. Keep in mind that the new plant would be the same age as the original, even after growing new roots. This will mean that it will come with the same problems as the aging tree. It will just be a little smaller.
These articles will offer some information on pruning and caring for the plant:
https://www.gardeningknowhow.com/houseplants/philodendron/pruning-philodendron-plants.htm
https://www.gardeningknowhow.com/houseplants/philodendron/repotting-tree-philodendrons.htm