From all of the practical experience you all have gained growing lilies over the years, how important do you think soil pH is for successful establishment and growth of lilies? A lot of lily books, for example, state that Lilium henryi and L. candidum are only happy in alkaline soils whereas L. auratum and L. speciosum will perish if the soil is not acidic.

What are some ways you have found to manipulate soil pH, or even the lilies themselves, to successfully culture the more "nitpicky" species and hybrids?

Acidic soil seems to a precursor to longevity of oriental lilies here in the far north. But I don't mean acidic like for blueberries. About pH 6.5 seems to be low enough for my auratum and speciosum spp., although lower might be better. just don't know.

pH has more influence than just nutrient uptake that general information zeroes in on. It plays a huge part in what kind of soil flora proliferates and what kind of pathogens can get the upper hand. It's part of the big picture, in other words.

I don't grow Lilium henryi, simply because I haven't got my grubby hands on a good upright strong stemmed clone. It hasn't been a priority though, especially since I have L. rosthornii that I subjectively consider superior. I did grow L. henryi to flowering from a 1/4" bulblet in my teens, in regular vegetable garden soil that would have been neutral to slightly acidic. It was very vigorous.

Hybrids seem to be quite adaptable, as do many of the species.

Great information, Rick! I never made the connection regarding pH vs. susceptibility to certain pathogens, but it makes perfect sense. A happy, healthy plant grown in the conditions it prefers will the have edge on fighting off infection more than a sickly specimen of the same plant.