Landscape fabric? mulch? over already existing plants?

i have large flower beds that i am in the process of planting but i am short on money and it is taking a while and i am finding that i am spending most of my time keeping them weeded but i already have some plants in them such and a section of them is done in lilies and i have a few small bushes i was interested in landscaping fabric and mulch but will my lilies be able to grow through it in the spring? ive used newspaper layers successfully in other parts of my yard under the mulch instead of the fabric but their was nothing planted in those areas yet, would they grow through the newspaper? also the lilies when if ever could i cut back the foliage to those lilies after they have bloomed?