Here's an interesting question, as it's too cold and miserable for me to go out to work:
"Can I use Leylandii clippings to make the soil more acidic for my acid-loving plants?"
Interesting, as it challenges a few assumptions. And you all know how much I love assumptions! ("Not".)
I've always understood that the soil under conifers of all types becomes very acidic, as - so it's said - the rain washes the acids out of the needles/scales onto the soil below.
So it makes sense to say that a mulch of pine needles would help to lower the PH of the soil.
By the way, if you can never remember which way the PH goes, try thinking of it like this: back in the Swinging Sixties, mad hippy types took LSD or "Acid" and frequently had "like, really bad trips". (Simple moral lesson, kids: Drugs Are Bad!) So, taking illicit drugs makes you poorly or "low". Acidic soil has a lower PH than normal soil. Acid = low.
Also, with regard to Hydrangeas, acidic soil (which is it, high or low? Come on, you just learned it! Low, that's right) makes blue flowers. Feeling blue today? Feeling a bit low?
Acid = low PH = Blue flowers.
Right, where was I? Oh yes,
Certainly we are all familiar with the bare brown earth under a line of conifers, especially those fiendish Leylandii that suck all the life out of the ground for a foot and a half on either side.... but is this due to the acidic soil, to lack of water, to lack of nutrients, or any combination of the foregoing?
No-one seems to actually know! I have searched the internet and have not found any firm answers, just an awful lot of forums with anecdotal stories such as "I spread my Leylandii chippings on the garden and it has suppressed all the weeds perfectly. However, my peonies have all died" which makes you wonder about some people.
Perhaps I will have to get myself a soil tester, and do some field study.
When it's a little warmer, perhaps!