It helps to know which specific plants you are asking about? Rooting techniques vary with different types of plants. It's a case of "one size doesn't fit all".
There are different ways to propagate plants. A lot of it depends on the material you are working with. Leaf cuttings are made for soft herbaceous plants like African violets. Most plants do better with tip or tip and stem cuttings (semi ripe or hardwood). Things like breadfruit are usually propagated by roots or root suckers. Some plants are water rooted but most use some type of media, perlite, vermiculite, sand or even potting mix.
The time it takes for cuttings to root depend on the type of cutting, season, temperature and plant. Most plants root easily if cuttings are taken during the active growing season. Rosemary will root within 6 weeks when actively growing but take up to 7 months when it is not actively growing. Bay leaves take 5-6 months to develop a healthy root mass although the leaves will start growing sooner.
Some things like cactus and succulents should be allowed to callus before planting to keep them from rotting.
I have been frustrated by not being able to root my Bay cuttings, glad you mentioned this Coincidentally, I will be rooting some African violets soon, so this post was unusually helpful
Just a little general tip to add -- humidity really makes a difference for cuttings. Initially they have no roots, so no way to take up water. An easy thing to do is cut a 2 liter soda bottle in half horizontally. Put some moist potting mix in the bottom half. Dip your cutting in rooting hormone and plant it. Then put the top half back on for a humidity dome.
Whenever the opportunity presents itself, the way I prefer is ground layering. Bend a branch to the ground and lay a brick or rock on it, or secure it to the ground with a U-shaped wire. You want to ensure that a healthy node has contact, and that a significant growth tip is sticking out beyond the grounded point. Some people bury the contact node a bit, I usually don't.
Then the only thing you need to do is wait and not disturb it. No worrying about seasons, humidity, anything really. When you see that it is growing and resists a moderate tug, it's ready to cut from the mama and shovel up the new root ball. Whenever you're ready too, and it's a good weather day for it, it should go from attached to mama to installed in a new location in about 15 minutes.
If a branch won't reach the ground w/o breaking, a pot sitting next to the mama with soil to the rim can sometimes "raise the ground" to a workable level. Spring is a great time to get started, you'll likely have something to transplant this year. [/I]
Thanks!!! all of you sooo very much I will def keep you updated I will try the ground thing so just bring one of the branches on the ground and stick a brick on it and it should root from there?
On Bay leaves. I wait to take cuttings until I see that the tree is getting ready to put out new shoots or coming out of dormancy. I take cuttings at least a half inch thick and 4-6 inches long.
The bay will have to live on the stored food for a while, thinner cuttings don't do as well. Remove most of the leaves. I have used both dip and grow and rooting powder, they have both worked.
I root everything in perlite (it just works for me). I do my cuttings outdoors so I just keep it under my planting bench. After three months there is a single fine root, but usually not enough to survive transplanting. After 5-6 months there is a good root mass. When the leaves start growing, I will give them a foliar feeding.