You can use a jam-fit curtain rod inside the window frame, attach strings to it and train the morning glories up the strings. You can find the curtain rods at DIY and bed-n- bath shops. You probably want to purchase a pretty heavy one just so it'll support the weight. For that matter a shower curtain rod might be a better choice. It will probably hold better and wouldn't bow under the weight of the plants. Purchase the color of rod that blends in with the paint job and hide it behind the mini blind. Use twine or other fairly sturdy string for the plants to climb.
Let us know what you decide on and please send photos. Good luck!

For a lightweight trellis, my first thought would be
to buy a cheapy package of the flowerbed 'fencing'.
Wire the pieces that usually go in the ground, together.
Buy some suction cups to go on the windows, to fasten the
'trellis' to. You could also get a couple of very small nails, like paneling nails,
put them into the pine board on the very edge, inside the window-the holes
would not show when nails are removed. In fact, if you
put the nails where the board joins, in the seam, whatever it is fastened to they
definitely won't show. Tie fishing line on one side and run it through the 'fencing'
and tie it off on the other side. The kind of stuff I am talking about is metal and
has a scalloped top. usually not more that $2 for several pieces at Big Lots.
Does this make sense to you?

Depending how the mini blind is attached you can tie fishing line to it and tie small knots in it to train the morning glories up it

At garden centers they have window box trellises that fit on the sill

Thanks! The flat pine boards around the frame are actually about 1/4" to the right of the vertical inside boards, and then painted, so you can see that inside seam, and if I were to put even panelling nails in, they'd show. :(
BUT...I might be able to get away with pounding in some straight-pins, which I've used to hang small pictures & accessories at home, so would imagine that they'd hold a bit of fishing line tied to them on the outside edge. (Pounded into the seam where it meets the sheetrock). I may also be able to use push-pins...you know...put up some memos that I never read as though they are reference materials...hehe

BUT...I think I can definitely work with the jam-fit rod(s) and some fishing line! I could put one vertical, and one horizontal, and make a 'grid' with the fishing line so the plant covers a portion of the upper-corner of the window. The mini-blind is mounted RIGHT AGAINST THE WINDOW, so putting behind is also not an option >:(

Thank you SO much for the ideas! I knew I could count on this group!

you can also use bamboo pushed in the pot and tied together at the top for a teeppe. Use smaller ones and then add taller ones later. But I like the expansion curtain rod idea also.

I decorated our first Real Estate office in Garden Style.I had two lovely trellises on the wall and wrought iron furniture.I added alot of bird houses.When we moved to a larger more elaborate office I put those trellises on my wall in my home.I love them.
I would not have considered growing morning glories inside but I just spent the entire day reading for Ag Literacy Day at an elementary school.One class had started morning glories in the window and I couldn't believe they were so happy.Good Luck!

I once potted some plants in a long plastic rectangular planter (like a window box) and used the decorative metal part off an older storm door (the guard with scrolls on it to keep you from tearing out the screen) that I stuck in the planter as the trellis. The pot should be longer than your metal part. Just stuck it in the dirt, leaned it toward the window and it looked great. I spray painted it white, the pot was green...a very gardeney look.

Can't believe I found this thread! I too have a plant that I'm growing indoors. It's a native honeysuckle vine that I bought on eBay, and that has--against all expectation--grown steadily despite an utter lack of sunlight. My cubicle is quite large, with plenty of space on top of my cabinets for a trellis of some kind, but nowhere that I can lean a trellis against. I was hoping perhaps someone had tips on creating a free-standing trellis that will be sturdy enough to accomodate a growing plant (and hopefully multiple vines once I figure out how to propagate my baby!). I'm a gardening newbie, and anxious to keep this little miracle alive!

I just love A L L the ideas !!!!
Sounds like fun....
and sounds good to me since it is so dang cold I hurt...
I like to think of something growing..
and ssomething hanging.... etc...
Something green and SPRINGY!!!!!!
Thanks for the IDEAS!!!!
SusieSunShine

I tried something with a trellis outdoors last summer that would also work indoors. I took a large flower pot, one of the lightweight ones without a hole in the bottom that only look like clay, and poured concrete in it and stuck a trellis in the concrete. I used a pot that was deep enough that I could add soil on top when it dried and plant in that. Or you could plant in small pots and place them on top of the concrete around the trellis and add moss to cover the pots. This may work better as they could drain.

These tripod plant trellis fit nicely in a potted plant indoors or on the patio. See the link below:

Here is a link that might be useful: Indoor Plant Trellis