I haven't tried incarnata but I have rooted a number of other passies. I have great results rooting cuttings in plain water on a seed mat. I use an air stone in my rooting jars. If you don't use an air stone just make sure to change the water often.
Karyn

Posted by msbatt 7 (My Page) on Wed, Apr 25, 07 at 13:13

I've had the most success in rooting passies using florists' foam ('wet' foam) as my rooting medium. Soak the foam for 10-15 minutes, then cut it into small cubes no more than an inch on a side and place them in a shallow tray with enough water to come half-way up the sides. Cut your passie cuttings into two-node cuttinggs, snipping about a quarter-inch below the bottom node. (Note---it's EXTREMELY important to be certain the 'bottom' node is actually the rootward end, and it's EASY to get confused with passies---always work from the tip down, just to be certain.) Carefully remove the bottom set of leaves, and I usually rreduce the size of the leaves on the top node, too. Dip the bottom end in just a touch of rooting powder, and insert them into the foam until the bottom node is just barely below the surface. Place the tray in bright but indirect light, and keep the foam moist at all tiimes. Once you see the roots coming through the foam, they're ready to pot up. As the roots grow, they'll break down the foam by themselves.