A gray/green color would be very soothing.

Would a paint with a green undertone not look rather cold in a room which kind of faces north? Was wondering about a fairly strong warm taupe / beige / moccha colour?

You need much taller lamps so that you could read in bed if you want to. As for wall color, I would do a much lightertone of the purple in the drapes, and no taupes, beige etc.

I would use one of the purples for the walls

"Warm colors are often said to be hues from red through yellow, browns and tans included; cool colors are often said to be the hues from blue green through blue violet, most grays included."

Given the above, and that the room looks narrow (not sure how long it is) and that you wanted a warm color, I'd be taking a sample of the proposed carpet and the curtains to a paint store. I never thought I'd use beige, but I have used SW Softer Tan, and SW Irish Cream paint colors recently, and been very pleased with the neutral results. The Irish Cream in a powder room is shown below your fabric pic.

I'm not suggesting that color, but I WOULD take your carpet sample and the fabric (curtain panel) to a paint store and walk them along the paint sample displays. Some colors will appeal to you. I look at the colors of the branch that the Capuchin is clinging to, and would personally start there. We can't see the true colors here online.

That is just IMO, as I cannot stand purples.

I agree to go with a pinkish or purple choice in paint. The pattern in the fabric is quite vibrant. How bold do you want to go in the bedroom? I am afraid a green would be a bit "swampy" in a north/west room, unless you go with something very vibrant. I do not recommend taupe or beige.

I would also recommend taller lamps to frame that wall as a focal point and for reading in bed. Also, would you ever consider painting the furniture? If so, I would paint it either rubbed white, or a green.

Linen , natural color will warm your bedroom up.

There is a light tan/khaki color in the curtains -- matching that would be a great look for your walls. Just avoid getting a tan w/a pink or yellow hue.

Lovely fabric and curtains : ) . The green in the Sanderson fabric appears to have a yellow undertone, so it's more of a warm green than a cool green. You just have to decide if you want to be cocooned by purple, green, pink, or a shade of brown in the fabric. I would probably choose a warm mossy green.

Consider switching out the lamps for something like this,

https://www.homedepot.com/p/Safavieh-Pamela-27-in-Fern-Green-Triple-Gourd-Ceramic-Lamp-Set-of-2-LIT4095G-SET2/204848638

https://www.homedepot.com/p/Safavieh-Pamela-27-in-Dark-Purple-Triple-Gourd-Ceramic-Lamp-Set-of-2-LIT4095K-SET2/204848641

https://www.homedepot.com/p/Safavieh-Eva-24-in-Dark-Purple-Double-Gourd-Glass-Lamp-Set-of-2-LIT4086K-SET2/204848533

https://www.homedepot.com/p/Safavieh-Eva-24-in-Fern-Green-Double-Gourd-Glass-Lamp-Set-of-2-LIT4086G-SET2/204848530

More styles here in those two different colors,

https://www.homedepot.com/b/Lighting-Lamps/Safavieh/Green/Purple/N-5yc1vZc7pdZ4kxZ1z0tup6Z1z0tvne?NCNI-5

I'd also consider simplifying what's over the bed. One larger print/picture or mirror rather than two smaller, busy ones. A large print playing off the curtains might be nice -- perhaps a botanical with an amaryllis or a pomegranate, or one with a parrot. A cheap way to do it is to get a book like this,

https://www.amazon.com/Botanical-Prints-Hortus-Eystettensis-Selections/dp/0810927438/ref=sr_1_6?s=books&ie=UTF8&qid=1514338517&sr=1-6&key

and then find an inexpensive mat and frame; best would be a mat as wide as possible with a frame as big as possible.

how daring do you want? I was trying to find some examples to give you an idea.

imagine a fuchsia wall (or the green or the plum) just behind the bed, and the other walls the same white as the curtains (you'll have to use your imagination on this pic)

deep plum accent w/white walls or do the entire room:

similar print w/a simple tan or off white wall. blah.

ceiling? off white walls.

I love those Beth. You do such great work!

Burlap color will be good here.Get couple tall nice lamps and quilt/coverlet with pillows in purple color.

here is one accent wall in Eminent Bronze SW

Accent wall Burlap SW

An accent wall would make this room look even smaller. I like the wall color as it is with the purple accents in the room, which somehow make the room look larger, and certainly much more elegant.

Just my personal opinion... I do not find purple to be a warm color. I know it is just my taste but thought I would chime in.

I think your room already looks warm and cozy. What is your wall color?

I am one to go dark with wall colors (given certain circumstances). My living room is painted a dark green/brown called Brainstorm Bronze. We have many windows and I was trying to warm up the space. It definitely warmed it up!

Behr's Graylac? It's a very soft, greyed lilac.