
Here we have a Passion Fruit growing amongst some raspberry bushes. (Note that raspberries prefer plant division for propagation) Passion Fruit is a vine that is native to South American rain forests. The plan gives many small, oval-shaped fruit, of which the flesh and seed is edible. It tastes like a mix between grapes, apples, and pear all mixed together. As with most vines, it is good to prune off pieces that will not give fruit. These clipping are perfect to use for cutting propagation.
The general rule for taking a cutting holds true for almost all plants that propagate well by this method. Select a branch from the mother or mature plant that is between ¼ and 2 inches thick. Cut the branch off with a very sharp knife or pair of shears. Make the cut directly below a node (place where new branch and/or leaf comes off the main branch), as this is where the highest concentration of stem cells is located. We want stem cells, as they are capable of turning to root cells very quickly. Make the cut at a 45-degree angle as this also encourages root cell development.

Generally, the length of the cutting should be 4 to 8 inches, but can be larger or smaller, depending on the plant. The idea is to plant 2/3 of the cutting underground and the last 1/3 above ground. You thus need to remove all the leaves on the 1st two-thirds of the cutting, as well as all of the leaves that are on the lower half of the piece of the cutting that is above ground. Basically, you only want about 3-5 leaves on the cutting and only on the top 1/5 of the cutting.
Note that you may be pruning a tree that you wish to take cutting from and you select a branch that is 2 feet long. You can make four 6” cuttings from this one piece. Just always cut at a 45-degree angle and right below a new node on the branch.

Here you can see two new Passion fruit cutting planted in old plastic water bottle halves. Make sure to put holes in the bottom of your containers and to try to use a soil mix that is more towards the sandy side. Also, try to keep the humidity high around your cuttings. It is useful to devote one little shaded area in your garden to be a nursery, which can be kept moist and cool all day long. Some cuttings can be left in water first for several days and then transferred to a soil mix, but it is not necessary.
A word on rooting hormone: Many places offer rooting hormone, which is applied to the tip that is being planted in the soil. While these hormones are probably helpful and effective, they are not needed. In case you have not figured out yet, I believe that gardening should be a free activity and no special equipment should be needed. I also believe that there is a natural alternative to all commercial products. This instance is no different.
Willow trees, which grow near lakes and rivers and are the natural source of aspirin, offer a substitute. All you need to do is mash up a handful of willow leaves and apply this poultice to the tips of your cuttings and success will be greatly improved. Again, there is no need for this. The best part is, taking cuttings from mature plants is free; all you need is time. So take a bunch of cuttings and wait. If they all die, try again.
Keep the soil around your cutting wet and the air kind of moist and in 1 month or so, they should be ready to plant out.