Lime will probably help

Waplummer, thanks. I thought so but just wanted sonfirmation.

I've been watching for you to repost on the thread I started "Evaluating Shade Groundcovers". You said my choices seemed mismatched and I've been waiting for further advice and suggestions:-)

Why not buy a cheapie ph meter and test your soil then compare it to places where you see your plants doing well before you lime? That's what I do, then I raise the ph with lime for stuff like hart's tongue and walking fern and lower it with sulphur for acid loving stuff.

I have a lot of the same stuff you mentioned and I just measured the ph this weekend, most spots it was just barely below neutral (6.8-6.9). I'll measure right next to where my T. grandiflorum is and post it if you like.

KWoods, That would be great if you could measure and post the results! I would appreciate that very much.

While it is true that T. grandiflorum seems to prefer sweeter soils, another truth is that throughout much of its range it grows in acidic soils. In the southern highlands where it forms colonies that can literally carpet entire valleys the soil's reaction is probably between pH 5.0-6.0. I think that as long as you are between 5.0 and neutral you're in the right range for this species. There are many other possible factors in your plant's health. PF

plantfreak, How can I determine what the other factors are? The trilliums are planted at the base of a wild cherry tree with the dwarf larkspur to their immediate right. To their left are several clumps of hepatica. In front of them is a clump of Iris cristata. Every spring I put leaf mold from my Dad's woods around the plants. I have never fed the trilliums ( or any of the plants, for that matter). Do you think I should?

I wouldn't fertilize them, yearly compost is more than enough. If you are unsure of their well being perhaps you could move one in the fall and put it in a situation that mimics the conditions of your grandmother's plants. Since all the other plants you mentioned are doing very well, I don't see that you have any problem at all. PF

Hi Vegangirl,

Took 3 measurements in 3 different spots around my T. grandiflorum, all were right around neutral (6.8 -7). These plants are all doing well but are grown in a garden not the wild.

Measured the ph in a relatives garden where the same trillium (gave her some of mine last year) are not doing as well and ph was also 7. Not sure why they are not doing as well there they're flowering but seem stunted and two have what look like varigated leaves (virus? maybe too much sun when they were emerging?).

Mine are in a fluffy humus soil that stays pretty moist, I might have added a little peat at one point. My "native" soil that is underneath the humus is very sandy and fast draining, great for growing lots of stuff.

Hope you find the right conditions for your Trillium to do well.

plantfreak, thank you. I think I will go to my Dad's and feel the soil where my grandmother's trilliums are and compare it to mine.

KWoods, thank you. I appreciate you taking the time to check that for me. Even our daylily patch where we added lime last year is more acid that that. It's 6.0 so I'm sure the un-amended soil is much lower. The woods around are full of rhododendrons.

I think I'll work in some lime too and see what happens.

Thanks for everyones help!

My trillium grandiflorum are doing great in my very acid soil. What they most need is a lot of organic matter in the soil and adequate moisture. I planted mine in a mixture of leaf mold and composted manure. They seem to love it. Make sure your planting holes are big enough so they don't have competition from tree roots and other plants. After I planted them last Spring I kept them well watered, which really helped them get established.

aspringer, thank you for the tips. My soil isn't as fluffy as the soil where my grandmother's trilliums are. Also hers were planted at the base of a big rock and mine are planted at the base of a tree. I guess I need to work in more leaf mold.

Apropos of the subject of the right conditions for this plant: I planted two trillium grandiflorum in March, in clay-ey soil in a shady area between an escalonia and a pittosporum, full of roots, which area is irrigated daily for a few minutes by an automatic spray. Neither was there when I tried to dig them up a few minutes ago. Looks as if they rot in too-heavy soil. (I don't know the ph.) By the way, I'm in Santa Cruz, CA, where the winter lows are usually in the 40's. We had a lower low this past winter, but that was before this planting. Anyhow, I'm bereaved. Perhaps through my most grievous fault. Whaddaya think, gang?

I would think that anything that goes dormant in summer as trilliums do would need a dry spell. I don't know how they behave in Zone 10 of course. Evidently they were not happy and I would suspect the daily watering but then I'm no expert. Maybe someone else will offer an opinion.