Here I'm am. Heard ya missed me
rebloomnut...Wow, zone 3/4. That's almost tropical! My thought is that cececoogan's post is probably appropriate for your area. I'm zone 1. While surprisingly we haven't seen it yet, we traditionally got down to -50 for a spell. Lowest this year has been -47ish. How cold do you get where you are in MT?
I grow a variety, but the only ones that are hardy are Asiatics. The LA's occasionally come back once, but then they disappear.
I have a labor intensive process which I wouldn't recommend any sane person start. All my orientals, trumpets (anything except the Asiatics) are grown in pots. Unpotted each fall. Semi-cleaned. Dusted w/fungicide. Stored in a refrigerator (Known as "The Lily Refrigerator" as opposed to my Honey's "Beer Refrigerator") at 34° from October to as long as I can keep them dormant in Feb/March when they are all repotted. They start their season's growth in a heated garage w/lights until mother Nature deems they can go outside, approximately June 1.
The stress usually causes some buds to abort in the garage
...but the majority go on to do their thing throughout our phenomenal summer till late August. The ones that abort stay outside in an area of the yard we designate as Purgatory so they can grow nice healthy leaves to go through the process again.
Also, while they will multiply, you won't have swaths or big masses of any specific lily. You will get multiple stems or multiple bulbs that you can plant in the same pot. I envy the wide open paths and patches you can achieve by leaving them in the ground each year.
Unless you choose to keep it at a reasonably number, it's a ridiculous procedure...I'm hoping you are warm enough, that with plenty of mulch or locations up against your home to possibly find some Orientals or OT's that are hardy enough to make it through your winters in the ground...Anything is possible if you want it bad enough so if you want more details about my process, I'd be glad to provide them.
What IS nice is there seem to be a lot more Asiatics coming out yearly to bring some diversification. I was getting bored with them, but seem to find new ones that are a bit different...try
http://www.farawayflowers.com/
I have several Orientals from her that have survived the abuse I put them through for 4 years so far. Her Asiatics return each year. Her customer service is exceptional.
