might depend on where you are as to whether the paper will decompose so that the bulbs can emerge ...

if it were me.. i would insert the bulbs.. and hit it all with RU ... then mulch heavily ... so that i insured any perennial weeds are killed ...

it highly depends which weeds we are talking about ... annuals versus hard to kill perennials ....

if annuals.. and all you are doing.. is burying the dying plants/seeds .. you probably dont even need the paper .... nor the RU ...

i know what you are doing.. lol ... hoping it will all be so easy ... we all wish for that ... but all i know.. is that i usually lose ... when i try to skip the hard work ...

good luck ... more info please ...

ken

It won't harm the bulbs but if the plants are really weeds it won't help. In winter they will just be dormant too.
If they are winter growing weeds, you can spray roundup on them and the bulbs will not be affected. Even if the bulbs are growing, and if the weeds are broadleaved, you can very cautiously use triclopyr (and that alone...NOT an herbicide with any other active chemical) and it will kill the weed w/o killing the bulb. But, you want to test for varietal sensitivity first. I did this years ago to clear daffodils of creeping charlie and the various similar Lamiaceae. However when I switched to a formulation of triclopyr + another growth regulator (clopyralid), I had problems.

simplest approach for you might just be: let the bulbs grow until midsummer. Cut them back. They will go dormant. Let the weeds regrow, correctly spray with roundup. That will kill perennials weeds; as for their seeds make sure nearby seed sources are controlled. I've found most of the weeds in my garden were coming from other parts of the garden where I did not consider them weeds. This is why I treat my lawn for violets. I don't mind the violets in the lawn but if you let them grow there they have a launch site for invading your beds.