Best timing of cuttings using any method always depends on what kinds of plants are being tried.

that post is in the plant propagation forum .... perhaps you ought to post there also ...

if you are going to try to root smallish tips ... you usually can not do it with fresh growth in spring ... they tend to rot.. long before anything else happens ... and you dont want to take cutting.. that will then flush out ... there arent any roots for it to do that ... and then live long enough to root ...

so that is generally.. why you wait until this years new growth hardens off in late summer ... before you try rooting ...

as embo notes .... its hard to hone in on an answer when you dont ID what you want to root ...

ken

The way I understand it, the reason for the toothpick method is that it gives the plant a head start on making callus material which is what a cutting does before it forms roots. So to me that would pertain to Hardwood cuttings or at least Semi hardwood cuttings, something that happens in the late Fall or Winter. I might be missing something so if someone would correct me on that if I'm wrong.

I'm not sure I understand your distinction - don't all cuttings callus before rooting, even softwood cuttings?

Sorry, I wasn't trying to say that softwoods don't callus, some do within a day or two. But certain woody plants, propagated by HW/SHW cuttings can take much, much longer (weeks to months) to callus so any jump start before the actual 'cut' can improve chances of rooting before time runs out and the cutting dies. Again just my understanding of what I read.

This is what was said in the first paragraph of the link posted above:

nandina(8b) 'This method allows the callusing to take place on the mother plant before the cutting is removed and is most helpful for those hard to root trees/shrubs. Plan to use the toothpick technique during the last weeks of August up until mid-September'

Can you tell us what plants you want to propagate?

I was wondering if the toothpick method would work on trees such as maples, fruit trees, and so on. And if it can be done in spring or is august the best time to it ? Thanks.

Hardwood cuttings or at least Semi hardwood cuttings,

==>> the new growth in spring is not hard.. nor semi hard .... so you wait til fall or winter ... we agreeing ....

to repeat... WHAT ARE YOU THINKING ABOUT PROPAGATING ...??? .... its hard to lead you when you wont guide us ...

also.. find out if your local library can get a copy of dirr's guide to propagation .... you have to do some of the work ...

ken

https://duckduckgo.com/?q=dirr%27s+guide+to+propagation&t=ffcm&ia=products