If you want to increase the size, I would go with a border and binding in either black or charcoal grey.

I would use a red to bind...but that's just me.

I like borders on my quilts, just my preference. When I made my one and only bargello I added my border but I also added the focal fabric into the border on the sides as if they were just running right off the page. Also added it thru the binding too which was fun to get it to match up correctly but that's how I wanted to finish it off and I was pleased with my extra efforts.

This so pretty! I love the bright colors you used. If you decide to go with a border, black (or navy blue) would really make the colors pop.

Suz,
That is a great idea! Love the look, it was worth the extra effort!

If this will be a wall hanging, I wouldn't even do a binding. I would do a facing which will just be on the back--there are a bunch of youtube videos to show you how. Of course, if it's a bed quilt then you'll have to bind it. I love it just as it looks!

Love the bargello!
 

I don't think it needs a border either. I would bind it with red but any of the colors in it would work nicely too.

Beautiful quilt! With the ones I've made I didn't border but I don't with a lot of my quilts. If you're wanting bigger perhaps darker of any of the colors in solids or a blender (I guess I'm thinking like a mat on a picture frame). Grey binding to be in the background of the beautiful fabrics you chose or again darker of any of the colors in the quilt to frame it. Look forward to seeing your finish so please post when you're done.

I love how snooze2978's bargello runs off too. Might have try that on my next one!

I'd go for a border
 

I would toss several prints alongside your top to see if there is one that "fits" then I would do a narrow border first pulling out a colour from the print and then a wider print border. This is what I mean... I made this while receiving radiation for breast cancer.

Beautiful, no border needed...:)