yes you can grow dl in zone 4. You probably need to stick to dormants. You might try a few semi evergreen and see how they do for you. I would not attempt evergreens if it were me. If you do not plan on hybridizing, you won't need to pay alot of attention to anything really other than just if you like the flower. Buy what you like. I have many many dl I paid $5-10 for and LOVE and some I paid closer to 40 for, and there is no difference really. I like to buy the cheaper ones anyway because you can spend a lot of money on a dl and then you may not like it's performance. I like to wait a few years and see what other people have to say about it before shelling out $. Parent plants just let you know who the parents were of a particular dl. or instance if you look at Plant C on a website, it may say it's parents were Plant A and Plant B. This is important for people who hybridize, you probably won't need any of that info really. Sometimes I look at parentage just to decide how I think a dl will perform for me. For example if I bought Plant Q two separate time and it died, I may shy away from buying it's children!
Seedlings are crosses (babies) that are usually not decided yet by the hybridizer if they want to register them. For instance, a hybridizer may row out 1,000 seedlings, but after 4 or 5 years only a dozen of those would be chosen to register, name, market and sell. The rest are culled (thrown out). Seedlings are not for sale until they are registered. (generally speaking)
http://www.daylilies.org/Dayli...
you can look here at the AHS registry to see if a dl you want to buy is registered and to find more info about it. Usually you can find it's parentage, height, bloom time (early, mid, late, rebloom ect, and if it is evergreen or dormant. ect. You can also see the hybridizer. This is handy if you prefer dl from a particular person. Some people hybridize for specific qualities, such as heavy substance, diamond dusting, ruffling, spider forms, ect ect. So if you prefer a certain type, you might specifically look up that hybridizer.
Be ware of companies selling dl that have names that do not come up on a search on the above link. They are most likely not reputable.
I think for zone 4 it would be best for you to find some growers in similar cold zones to buy from. If you bought evergreens, you could grow them in a green house maybe or potted in your house. But to plant them outside, they would most likely not do well. There are LOTS of dormants!
Here is links to some growers that you could buy from to start out with.
http://www.homesteadfarms.com/ (Missouri) (I love this place!)
http://www.cheryldaylilies.com... (Ohio)
http://www.lilywoodfarms.com/p... (Missouri- I have not ordered form here)
Maybe some of this will get you started!
