I have a new border in which I have planted a mixture of spring and summer flowering bulbs and shrubs. The bulbs include lilies, tritelia, tulips, and Ixias. I have also sown some annuals, including california poppies, calendula and nasturtiums. In order to keep down the perrenial weeds which include creeping buttercup I would like to lay a mulch approx 4″ to 6″ deep. I intended to use chipped bark as the mulch. Will the bulbs be able to penetrate this next Spring and Summer and will the annuals self seed and grow. If they can penetrate the bark mulch why can’t perrenial weeds? Any help/advice you can give in this respect would be appreciated.
Perennial weeds including buttercups will come thorugh 10cm of bark. it would be a waste of effort to put bark on top of weeds. Bulbs would come through but annuals would not self-sow on bark.
Control weeds by chopping them out with a spade. Bark is useful around shrubs and big perennial flowers when used on weed-free soil. If prevents weed seeds form germinating but will not control existing perennial weeds, just feed them!