I put different kinds of tree branches that I like into a transparent water container indoors. (If it matters, the types of branches I'm trying to do this with are Mimosa tree, tree of heaven, & northern catalpa). Would I be better off doing this another way such as in soil? I like water propagating because I like seeing the roots grow, I'm relatively impatient, and this is more of a science experiment and I won't be upset if nothing happens. Also, I'm newly interested in plants so I've got a brown thumb. Any tips or obvious things I seem clueless about would be nice too!

I think that as a general rule, in areas where we have four seasons, branches root more easily when similar bushes/trees are beginning rapid growth (spring). I also think it is best to use cuttings from the one year old portions of limbs. Cuttings from older parts of branches are less likely to respond by sending out roots. Of course some trees respond better than others, and some (pecan e.g.) will not root regardless what I do.

My experience (very limited) is that they root best in damp soil and with a transparent almost air tight bonnet over them. Just leave a little slit so they can breathe a tiny bit, but not big enough to dry them out. Put them in indirect sunlight.

Others with more experience will probably offer more, possibly better, advice.

do you have any experience water propagating?

No.

I never do because the roots are too fragile to transition to soil easily. If I start a plant in water, it stays in water forever.

Here is some information from my propagating books on the 3 trees you mentioned:

Mimosa - Stem cuttings from adult trees will not root, however, root cuttings are extremely successful.

Tree of Heaven - Root cuttings regenerate shoots readily. The shoots can be severed from the root systems and rooted like stem cuttings or the entire shoot-root potted and grown on.

Northern Catalpa - Cuttings late December, hardwood, open bench 8000 ppm IBA-talc plus thiram, rooted 50 - 75%

Maybe you should try seeds? All those trees grow well from seed. You may have to stratify the seed though.

Sorry to be discouraging, but if what you're calling Tree of Heaven is Ailanthus altissima, it's an invasive weed tree, not to be encouraged. We have it around here... impossible to eradicate. It would be great if your could find some native or friendly species to propagate.
https://www.nature.org/en-us/a...

Yes I am aware what it is and that it's invasive. I also think it's a really beautiful tree. I wanted one just as a little houseplant, so there's nothing that I am encouraging.

Ah, good. Could make an interest bonsai. Grows really fast.

There's no harm in trying. A propagated twig would give a great head-start on bonsai. Bonsai is a great way to enjoy an invasive tree like mimosa (Albizia julibrissin). The tiny leaflets are perfect subject matter.

I've rooted countless snips of so many plants in both water and soil and IME, woody entities are more likely to rot than take root in water. I think you'll have better luck with soil, and, as said, trying in the spring when vigorous new growth is occurring. Whatever you decide about timing or method, try to cut at the semi-hardwood point. Check weekly for rotting at the cut end and re-snip if you see that happening. Best luck!

There's a propagation forum here.
https://garden.org/forums/view...

This discussion has been going on for a while and shows a LOT of propagation experiments.
https://garden.org/thread/go/2...

DaisyI said:I never do because the roots are too fragile to transition to soil easily. If I start a plant in water, it stays in water forever.

Here is some information from my propagating books on the 3 trees you mentioned:

Mimosa - Stem cuttings from adult trees will not root, however, root cuttings are extremely successful.

Tree of Heaven - Root cuttings regenerate shoots readily. The shoots can be severed from the root systems and rooted like stem cuttings or the entire shoot-root potted and grown on.

Northern Catalpa - Cuttings late December, hardwood, open bench 8000 ppm IBA-talc plus thiram, rooted 50 - 75%

Maybe you should try seeds? All those trees grow well from seed. You may have to stratify the seed though.

Forgot to mention... This information is direct quotes from "The Reference Manual of Woody Plant Propagation" by Dirr and Heuser. I didn't make it up.

"Hartmann & Kester's Plant Propagation" says:

Mimosa - This species is propagated by seed

Tree of Heaven - Easily propagated by seed. ... can be propagated by root cuttings.

Catalpa - Seeds germinate readily. Propagated in summer by softwood cuttings. Hardwood cuttings with 8000 ppm IBA-talc. The terminal bud should be removed.

I doubt you will get better information in the Propagation Forum but go for it. Let us know how your cuttings do.

You might still be able to find seeds on or around the trees. I saw Mimosa pods hanging here this week
Goo d luck with what you choose!

I didn't mention propagation forum as an alternate source of info but because there may be previous posts about propagating these same trees. And in case Joezoe might like to have a discussion in a section where discussions don't fall off of the page so quickly.