This is my method for making inexpensive bendable waterproof vines. The process is very simple, made from easily available items but somewhat messy. You should be able to make about 50' of vines for around $15, more if you choose to add leaves.
Rope - I used the 1/2" natural Sisal Twisted Rope
Great Stuff - I used the Great Stuff brand Windows and Doors
Tape - I used electrical but duct or masking would work just fine
Floor Cover - Cardboard, news paper whatever you have laying around.
Rubber Gloves - most important of all!
Knife or scissors
If this has been done elsewhere I'm sorry and didn't mean to steal your idea... I just wasn't lucky enough to find it before I made my own.
If you get hurt, blind yourself, or glue your face to carpet I hold no responsibility. Be smart be safe, don't cut corners and use the proper safety gear.
Step 1: Get Your Area Ready and Prep the Materials
You will need a space where you can hang the vines to dry. I've done this in my basement hanging from the rafters.
1. Layout the ground cover under where you vines will hand to dry.
2. Cut a length of rope to meet your project needs. In theory you could do all 50' as one giant vine.
3. This step is not necessary but I pre-stretch the rope and help get the coils out from being stored in the packaging. I use my bench vice but you could use a clamp or tie the rope to something study. Stretch out the rope and pull as hard as you can.
4. Tape the ends of the rope to prevent it from unraveling or tape several feet up from the end and untwist the 2 or all three of the strands. Doing this gives your vines some spreading smaller vines at the end.
5. Another optional step is to loosen the ropes twists to make a more bulky fibrous vine. While I have the rope in my vice I place the free end into my cordless drill, set your drill rotate in the opposite direction of the rope's strand twist. Run the drill till the rope coils on itself. Release the rope from the drill chuck, be careful when you release it from the drill chuck as their is quite a bit of stored energy in the rope. The rope will untwist almost back to its original state. You will notice the rope has a lot of loose hair strands and the twists are looser.
6. Cut several 2'-3' lengths of the garden twine tie them to the vine at various points.
Step 2: Making the Vines
1. Hang the vines from your rafters, clamp or whatever works for the area. The vine should be several inches from the floor. If your vine is longer than your hanging area, place the extra out of the way for now.
2. Put on the rubber gloves and safety glasses.
3. Starting at the top lay a decent bead of great stuff along the length of the hanging rope.
4. Smear the great stuff into the rope with your glove covered hand.
5. The best method I found was to cup my hand loosely around the rope and spay the great stuff into my hand as I slide it down the rope. Make sure the coating is very thin and occasional think patch is fine. You want to have as thin of a coating as possible on the rope.
6. Do you best to evenly coat the rope. You can always do a second coat if you missed an area.
7. Let it dry for about 30-40 minutes.
8. If you missed any spots you can just repeat the process. More than two coats may start to reduce the flexibility.
If necessary repeat the steps for the remaining rope.
Step 3: Paint Your Vines
Once dry the vines should look similar to the picture shown. The vines are very flexible you could tie a knot if needed. Keep in mind this is semi rigid foam so some cracking will occur.
To paint the vines you have several options. You could spay paint it (great stuff doesn't melt like other foams) hand paint or my method of dipping it.
Wear gloves if you plan to dip it.
1. I used a 5 gallon bucket, poured in a gallon of black paint.
2. dip the vine into the bucket
3. as you pull the vine out run it slowly though your hand wiping off the extra paint.
4. Pour the paint back into the can.
5. Hang the vine over the bucket to drip dry.
6. Dry brush with white paint, wiping off as your go.
7. Add several layers of different paint starting with the darkest moving to the lightest color.
Step 4: Finish It Up
At this point its ready to go as a jungle or swamp vine, if you choose to add leaves you can glue them, or use garden wire to tie them on.