Hi everyone. I was wondering if you had any suggestions or tips on overwintering my procumbens nana cascade. She was gently repotted in an oversized cascade pot this spring and had a great year of growth.
Last year I was able to put it on the ground but now the cascade is too long. Right now she’s on a retaining wall but can’t stay there all winter as I live in SW Pa, zone 7a/b.
I have a tunnel/tarp greenhouse with zip-open windows and doors. (Photo attached)
I had a juniper cascade that I would over winter with the pot buried in granite chicken grit and peat moss. I live in zone 5. I use
landscape blocks and cedar fencing surrounding my winter storage. To get it protected up to the trunk I would lay it down with the trunk directed upward. The pot needed to be stabilized to keep it in the correct position. I usually had my adjustable benches over the alley the trees were in to protect from the heavy wet blizzards that may damage the branching and foliage. Our winter was pretty heavy that year! The important goal is to keep the temperature pretty stable during dormancy. Frequent freeze and thaw in a greenhouse is more dangerous than staying at 25 to 35 degrees fahrenheit. The snow cover helps to ensure moisture and stable temperature, so as soon as it snows I lightly shovel it around the foliage.I have a cascade procumbens as well, and live in Zone 5. I’ve kept mine in my unheated garage which is usually 5-10 degrees (F) warmer than outside for the past 4 winters. Depending on how much the outside temp changes, it will take the garage 2-3 days to match the outside temp. The procumbens has continued to do well.
So my question is how much light do the junipers get during hibernation? My outdoor system give them lots of sunshine, until they are covered by a foot or more of snow! I keep my juniper and pine in colanders in my garage but keep led lights on to give some small level of light. The artificial light is not much, but it is more than a dark room. The accumulation of sugars into the branches and roots to increase cold tolerance continues until November- December. So I try to keep the sun loving species in light as much as possible. If this is wrong, I am still not to old to learn a better way. Northern USA and Canada have a special situation that require protection from prolonged freezing. So each person must find the system that works for them. If a species does not tolerate my system, it leaves my collection. So I have a smaller selection of species I work with.
I’m planning on just laying mine down on their sides with the trunk facing upward. Works for the square pots but the round pots need a little extra work to stabilize them. I can otherwise leave mine outside unprotected in Portland OR
The bench in the garage is next to the back door which has a 2ftx2ft window that faces Southwest. I keep the evergreens on the end of the bench closest to the window, so they get as much of the sunlight as possible during the winter. The deciduous trees go on the end of the bench furthest away since they don’t need the light.
Round or oval cascades.
I use rubber padding and one or two paver bricks. I then zip strip them together to keep the pot oriented with the foliage in the direction intended. Mine are covered with granite grit and peat moss to protect from our variable temperatures. Keeping the pot stable is important in my experience.
I live in canada and I keep my cascading juniper on an outdoor table near my house for the winter. works just fine
The more important question is what plant hardiness zone are you overwintering the tree. Victoria BC is zone 8-9 and has amazing climate to grow conifers! I live in zone 5 and have big wet snow fall and desiccating wind during the fall, winter and spring. As a result I need to protect the containerized plants to survive the harsh conditions. If I put the hardiest juniper or pine on the ground without protection, they will freeze, thaw, blow over and desiccate. 
