I’m a fairly new gardener and this year, I graduated from purely annuals to perennials. I also put down mulch for the first time but for some reason, after it rains, I seem to have a thousand tiny weed heads poking through the mulch. There even seem to be more than I had last year with no mulch! They’re easy to pull out because their roots seem very weak but it means I need to move the mulch, weed and then put it back. I was expecting a “weed free” border this year. Am I terribly naive or have I done something wrong. Any help would be appreciated.
You are neither naive, nor wrong, just becoming an experienced gardener! Every garden is a little different and it is through trial and error (many errors) that we begin to know the land we serve.
So, how come the weeds? Well, depending on what kind of mulch you used, the seeds may have been in the mulch. If you used compost, or hay, or something else with lots of ingredients, and potential seeds, the seeds could have been already present just waiting for water and sun to sprout. This mulch is meant more to better your soil, than to be used in weed prevention. If you used bark chips, or something very uniform, not made from the seed portion of a plant, it is unlikely to contain seeds. This is the best kind of mulch for weed prevention.
Also, how deep did you spread the mulch? It should be from 3 to 5 centimetres in depth. Any less and it is very easy for weeds to pop through. Finally, you may have spread the best kind of mulch at a perfect depth, but seeds from neighbouring weeds have landed on top of the mulch and begun to grow. We’ve all seen dandelions growing in cracks in the sidewalks. Weeds are very tenacious and determined to grow whatever the conditions. I wouldn’t take the time to remove the mulch, pull out the weed, and then reapply. Just yank out the offender. You mentioned that the root is weak and comes out very easily. Just grab it close to the soil and pull it out. The less you disturb the soil, the better. Keep at it, you’re doing fine.