I have several Peggy Martins in Zone 5b, central Illinois. They have done well over winter even with temperatures dipping below zero. I don't have to trim much dead wood. I planted the first ones in summer 2019 and in just three years, some have grown to 15 feet covering a massive amount of height and space. I even did cuttings and they sprouted and grew. I ordered more this year and will line all my fence with them. I will post several pictures

I don't use burlap either, I don't see the return for the effort. Other cultural practices have a much greater benefit. Rhododenrons are pretty tough to grow well in southern Ontario, they require lots of ancillary care. You need to make sure that you've got hardy varieties, the soil composition is correct (high organic, well draining, acidic), planted in a sheltered position (part shade, little wind), the rootball was scored just before planting, topdressed and fertilized every year, and some shelter from winter sun. I did a phenomenal amount of work to ensure conditions mimic a rhodos habitat which in southern ontario, is not easy. One of the biggest shortcomings are the dry summers which can be made worse if you have a thirsty tree nearby (especially maples). I water at least once a week during the summer. The other shortcoming is the soil, which unless you live on the Shield, is exactly the opposite of what is needed. Instead of trying to modify the soil, I just ended up changing it. As for varieties, the Yak, PJM, and Finnish groups are the hardiest but any zone 5 rhodo will work for you. The Dominion aboretum in Ottawa has large rhodos, as does RBG in Hamilton. Azaleas are easier! Simon

@Shad Burns I'm curious, where did you buy your seeds or vines from? I grow them too, and I'm always curious about the source of passiflora incarnata, when grown successfully in zone 5/6. Mine were selected from the wild, in Michigan, Indiana, and Ohio. I'm always interested in hardier strains. @Helene Albert I am in zone 5b, Chicago suburbs, literally a stone throws away from you. I grow passiflora incarnata successfully. I have fruit that's ready to harvest at end of August continuing through to October. It's truly a may sprouting perennial for me. If anyone is growing passiflora incarnata in zone 4/5/6a, please send me a message through Houzz by clicking my profile. I cannot send messages by default to most people, because messages are not enabled by default in Houzz until you go to your profile and enable them under "advanced settings." You should be able to send to me, however. I collect hardy passiflora incarnata. There is some genetic variation. Even the white version of P. incarnata aren't the same, with at least 5+ different strains floating around.

H. quercifolia is somewhat challenging plant for z5. The most of the problems will occur in a first few years. Once established it will be relatively trouble free plant, though not a reliable bloomer. After all it's a z7-8 (NC, GA) native plant. First, it need 2-3 years in ground to become fully established. Being technically root hardy to z5 it still need very thick layer of mulch and burlap wraping in a first couple of winters. Spring/early summer planting is highly recommended for z5-6. Second, of all hydrangeas, young oakleaves are the most succeptible to root rot while still can't stand drought. Therefore, one have to find PROPER watering regimen to satisfy this requirement. Again, thick layer of mulch could be handy. Third, it blooms on old wood and you are back to square one for winter protection as you would be with the most of macrophyllas. Winter protection ala 'hayseedman' for quercifolias will be not only questionable due to the rangy pattern of growth, but most likely will be impossible for the most of them due to their sizes, assuming they'll not die back every other year. 'Alice' in particular, is one of the largest h.q. and could easily reach 8x8' in just 3 years and 12x12' in 5 years if no dieback. IMO, dwarf cultivars, such as Pee Wee or Sike's Dwarf (both look identical to me anyway) are the only quercifolias that could be/should be attempted to grow in solid z5 on condition that grower is determined and will put reasonable effort to protect them. Fourth, indeed, fall foliage of oakleaves is a site to behold. However, in order to develop fall color it should be grown in a considerable sun, say 3-4 hours, and here you'll have another contradiction. Location with 3-4 hours of tentatively morning sun in a summer most likely will become a 6-8-10 hours of sun in a winter and such exposure most definitely will dry flower buds or even the whole branches by the spring, thus you'll have a huge non-blooming plant in a best case scenario. Sorry for the doom and gloom, but that is how I see it. Re: 'Blue Billow'. It wasn't me who touted it, but Hayseedman reported that it blooms RELIABLY for him in z6 WITHOUT any protection. In my z6b garden I don't protect any hydrangeas except trying to chose location wisely, and indeed B.Billow bloomed for me the last three years on a row, including very cold winter of 2003/04.