Hi Janet,
Most lilies prefer mildly acidic soil, including Orientals. That said, modern hybrids are pretty tolerant plants. While I haven't tested my soil I plant lilies right next to my home's foundation (generally a "no no" for plants that have a strong preference for acidic conditions like azaleas) and they do fine.

You can help your lilies by amending the soil with a LOT of peat moss before planting them. This will also improve drainage which lilies like. Give them the other things that make lilies happy (4-6 hours of direct sunlight) and they should grow fine.

You can also mulch the bed with pine needles in the Fall.

If you want to grow species lilies you'll have to be more careful. Some are VERY fussy about garden conditions while others are pretty tolerant of the non-ideal (such as Lilium Regale).

The only lily I'm aware of that actually PREFERS alkaline conditions is Lilium Candidum (the Madonna Lily). Maybe the other species related to it (L chalcedonicum and L monadelphum) also prefer basic soil (I'd have to look it up). But none of these are lilies you want to start with since they can be difficult to get going.

-Helen

My ph is in the range of what you have. I use peatmoss when planting them to amend the soil. I grow all kinds of lilies & daylilies & they all do find. Some times a new one will take an extra year to settle in & bloom but they all do fine & bloom great. Just plant what ever you like. When it comes to the Orientals I do give them an early spring fertilizing with 1 tsp to a gallon of water of MirAcid just to help them out a little & they bloom fine.

Janet, I think most of the new hybrids aren't so fussy about alkalinity, but I have had trouble growing Oriental lilies because of ph (I live in the desert, and have sandy, alkaline soil), so I did some research and decided to try growing lilium monadelphum. I have also seen this referred to as lilium szovitsianum . . . not sure what the difference is. It is native to the Caucasus mountains, and I thought it might do well here . . . and it does! :) It was slow to get to blooming size because I had ordered tiny seed-grown bulbs from Arrowhead Alpines, but it has been blooming very nicely for the past few years and is very pretty and easy-care. Hope this is helpful!

Lilium candidum (Madonna Lily)... loves the chalky alkaline soils. The harsher the better.

Agree with all that has been said. Since the pH scale is logarithmic, and you are near the neutral point, it won't take that much to lower your pH to neutral anyway. Candidum is an odd lily out, and should not be planted in fall. Mid-late summer, if I remember correctly, is the right time.

Szovitsianum and monadelphum are separate species, but very similar and lime tolerant. Especially monadelphum doesn't like to be moved as a mature bulb. According to literature, szovitzianum is the easier to cultivate, but I suspect there are also eyewitness anecdotes in dispute. Don't expect the vigor of hybrids from any species. They usually take a bit longer to mature.

Also Lilium amabile, an easy to grow species, prefers alkaline soils.