It's raining here, so you probably aren't able to shop vac up the lime...

Good news is our rain is mildly acidic.

In the wild, these plants are growing with a constant supply of dead organic matter falling around them (compost). Leaves and other organic plant remains release organic acids as they decompose; wherever accumulation is faster than decomposition, and acid condition follows.

Top dress your plants with compost, reapply as needed to keep a constant supply. If you haven't made your own, it's available by the bag (garden compost, or well composted steer manure) or the truckload. (mushroom compost is the wrong PH, so skip that one)

Dotty, now that I've thought about it a while :) Did your gardener happen to say why he is applying lime several times per year?

I don't think I've seen the recommendation for adding lime to lawns for more than once in Spring and once in Fall, most suggestions are for just a single Fall application. Understand that the focus of my yard isn't the lawn, but I put down lime only after rains begin in Fall.

Mor's suggestions are great - I'd also consider an application of chelated iron. As well as interviewing for a new gardener :-)

Get a new gardener? ( haha just kidding) Seriously I would put some peat moss or shredded bark around the plants. I also have been putting used coffee grounds (I get pails full from a coffee place) around my acid-loving plants and they seems to thrive on it as the coffee grounds are acidic.

Test the soil first before doing anything.

I'm putting a peat moss mulch on them tomorrow. Thanks for the suggestion. We are surrounded by huge fir trees so get a lot of shade and acid needle drop so they rhodies love it here -- except that the lime makes them yellow. The ones where the gardener can't get at them are lovely. The ones that he has nailed with the lime have yellow leaved. We have a LOT of moss in the lawn and I think we need it 3 times a year but I'll be doing it from now on with a drop spreader. Yes, I'm interviewing for a new gardener.

Dotty, is this a mulch that is part peat? Straight peat, or too much in combination with other organic plant remains, will shed water from rain or sprinklers when it drys out and then you have a second problem...dry root zone. It is the low PH you are looking for, but it's so far along in the decomposition process already not many organic acids are being released...I think it makes a better spaded in soil amendment than mulch.

I'd rather see you use bagged compost, or composted steer manure. Properly aged, steer manure is odorless and as easy to handle as potting soil...I throw it around plants in my mixed borders with my hands.

Circumstantial evidence points to liming but it may still, in fact, not actually be the problem. As always, it depends. For starters, is it hydrated lime or dolomitic lime? Cultivated soils here can actually be too acidic even for rhododendrons. Seattle Rhododendron Society newsletter actually starting recommending routine dolomite applications to RHODODENDRONS in January way back in the 1970s. In parts of China rhododendrons grow wild on dolomite formations.

I also live in zone8b Vancouver area.
I want to add lime to my lawn this fall, I have a hedge of rhodies along one side of my lawn. How far should I keep away from them when adding the lime to the lawn? Thanks for your help.

Add lime if you have specific evidence it is needed, such as a soil test report from a soils lab. Keep it away from the rhododendrons, although it might happen the soil they are in good benefit from some dolomitic limestone.

Do not apply hydrated lime to soils occupied by rhododendron roots.