They'll root, probably within two weeks.

How large are these branches? Larger material often takes longer to root, even in the case of willows. When I was a boy, I cut a large (1.75 inch diameter) piece of Pacific willow to use for a support-pole in a "fort" a few of us were building. The following spring, that pole had re-sprouted and was growing into a new tree. My first taste of willow vigor.

I started growing Weeping willow last winter, and all of my cuttings rooted. Toward the end of February, some of them were showing roots within four days.

If you plan on growing these trees, you might as well pot them now. I used a perlite/bark/gravel mix in 12 oz. water-bottles with the tops cut off.

Josh

say hey dave ...

gardening is an ART .... not a science .... no matter how hard the scientists try to make it such ....

e.g.: watering is not done by a calender... its done.. when the plants need it ...

as such.. rooting stock is not by calender ... it will happen.. when the plant is darn well ready to do it ...

if you were able.. to duplicate.. exactly .. EVERY variable EXACTLY the same as someone else.. you MIGHT predict the outcome of a garden experiment ... but you will never do that .. short of a laboratory/greenhouse ...

your slower rooting could be due to any of the following:

warmth of house...

24 hour cycle of warmth .. vs your house getting cold at night when the furnace is kicked down ...

water source..

tree source...

weather which affected the stock you cut

whats in the water you are using... city [chlorine] vs well ..

ambient light ... indoor light reduction vs outdoor/greenhouse light levels ...

the light cycle of the mother plant in mid winter ...

the health of the mother plant ... is it in drought in winter ....

etc ... ad nauseum ...

the best you can do...

change the water often.. never let it slime up ... and wait until the stock is ready ...

frankly ... i dont know how you can fail with willow/poplar ....

you will have to try real hard to not succeed .... wherein i would suggest you killed them with too much love ... forget about them.. they will root ....

good luck

ken

PS: if you have some forsythia available .. try rooting some of those.. they will flower in the house.. before they root ... and again.. you will not fail ....

I'll repeat what Ken said: change the water periodically, before it slimes up.

And pot your cuttings once the roots are a half-inch or so...basically, as soon as you have root evidence. No sense in wasting time in the water, when those roots could be growing far more vigorously in potting mix.

Let me see if I can find a pic of my elaborate winter-rooting set-up...
Here we go! Taken January 18th of last year.
Obviously, these are Pacific willow cuttings, but you get the idea. I kept the window open.
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Here's a little later in the season, with some of the Weeping willows now appearing:
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Closer (but crappy quality) image of my 'main' Weeping willow - compare growth to the next pic:
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Now for some bonus pics! Summer rooting!
When it came time to prune my W. willow, I decided to root one of the cuttings. After pruning, I potted the cutting (seen laying on the deck in the pic) in a mostly-perlite mix in a small Coke bottle. All of the leaves dried up and died, but a new tip emerged from the node just above the soil-line. When roots started coming out the bottom of the bottle, I repotted into a proper container. This willow is being grown in honor of my good friend Jon, a United States Marine. I hope he may one day return to claim this tree for his own...and, if not, I will grow it in memory of him.
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I can't wait until March when things really pick up!

Josh