Tree Planting on the Canadian Prairies - Considerations for best results; bare root vs potted trees

Here at the nursery we sell bare root trees, which is different from what you'll commonly see at the big box stores and large commercial nurseries where all of their trees and plants are offered in pots.  For the most part, being a mail order nursery bare root is essential - we just can't ship potted trees.  But there's more to it, and you might be surprised to learn about the benefits of planting a bare root tree and some of the hidden downsides of those large garden center trees sold in 10 gallon pots.

To begin I should describe my experience over the years with garden center potted trees - and some of the hidden surprises with them.   At the beginning of May on the Canadian prairies the weather begins to feel like summer, it's warm during the day on a good year, hah possibly snowing the next, but on average we'll see days and weeks where the temperatures into the 10-20C (60-70F) range and dipping down to regular frosts at night.  Deciduous trees are still dormant, just the earliest ones are beginning to leaf out.    This is an excellent time of year to plant dormant trees, the conditions are perfect.   So one might stop in at a garden center at the local Walmart or Home Depot and find that they brought in a shipment of trees, offered in large pots and flush with green leaves.  A bit odd you might think, these trees appear to have a head start on the season. Maybe that makes them better?   Of course this garden center knows best, after all they're selling truck loads of trees right?   You might quickly start to wonder if you ask enough questions to the staff, answers may start to get a little vague.   What nursery are these trees from?  Where is that, where were they grown?  Are they hardy enough to survive the winter here?  What climate zone are we in? How do you plant a tree?  While I think working in a garden center is probably a good job, you get to water the plants and meet with customers all day - staff often have very little expert training.  Occasionally you may find an expert gardener to speak with, a rare treat.  

So you're looking a tree, and sure this one looks nice - let's read the tag for more information. Upon examination of the printed tags, details are there but a little sketchy.  Sure the name of the tree, it needs full sun etc.. a barcode, a stock diagram of how deep to plant it, and on the back it says cold hardy -29C.  There's no mention of a climate zone rating.. and if you were looking for it, there's also No mention of the name of the nursery, location, or even the country the tree was grown in.. or the type of root stock used.  Wow so -29C seems cold, great - it's a tough tree.  But wait, is it?  In fact most of the Canadian prairies are in zone 3, if you're a little further north zone 2.  Zone 3 is -39C.   Our nursery is in southern Manitoba, zone 3b and every winter there are always days where the temperature dips to -40C.  This is one characteristic of this climate zone, the extreme winter minimum temperature.  It's not the only one, but it's important.   So armed with this knowledge, you might wonder - how much does this matter? If this tree can survive -29C, what's another 10 degrees colder, maybe it's fine?   Obviously this garden center knows it's fine, after all they're selling the trees right? They're not expecting me to drive several hours south into a warmer climate zone to plant it right?

Garden centers on the Canadian prairies are often stocked with fruit trees rated for warmer climate zones, imported by someone in an office who will never plant one of the trees, who likely doesn't live here and is concerned with the logistics of shipping truck loads of material from suppliers and stocking their shelf full of products (plants), and knowing that this is seasonal so it all will need to sell out within a few months. Stock is often brought in from the US from large mechanically harvested fields, these are wholesale agreements where the suppliers remain a secret, they're imported bare root then quickly potted up and sold disguised as container grown trees.   It's very common to bring one of these trees home, begin to plant it and only then realized the pot is filled with bark, hiding a burlap ball around a bare root ball that's been severely pruned.  Do I plant the bark in the hole? You might read the tag again for instructions only to be left second guessing. (Btw the answer is use the bark for mulch). On inspection of the freshly unwrapped burlap you won't find many small feeder roots, the thin hair like strands that are essential for the tree to uptake water - these were left in the field as the tree was basically ripped out of the ground by large equipment, are they're expected to be regrown.   These trees often have weak growth in the first year, it might survive - while it rebuilds the root system that was lost during field harvesting.  Can you find trees with an intact root system actually grown in it's pot? Yes, but they're going to be twice the cost.  If you can find high quality nursery stock like this, and you know it was grown locally these can be excellent trees.  A tree like this usually has 2 years of growth, the first year it grew into a whip (a single straight unbranched trunk) several feet tall, and the second year it grew some side branches.   If you do buy one of these, one consideration is many of those branches should actually be pruned off, they weren't selected and trained carefully - they were just let grow - and for the tree to have a healthy frame of scaffold branches with evenly distributed spacing that whorl of branches all within a few inches along the trunk just won't pan out in the long term, but a more in depth discussion on pruning and training will be in a following section. 

Bare root trees sold by our nursery are smaller, they usually have one year of growth after grafting.  We grow our root stocks for one year, graft in the fall or spring, allow them to grow for one full season, and the trees are available the following year.  So is the tree one year old or two?  Sort of both.  They're grown in raised beds of pure organic compost, a fluffy super fertile soil without compaction, which lends to easy removal with the goal of keeping the full root system intact. They're hand tended in small batches.   When you plant a bare root tree in the spring it's still dormant - meaning the leaves haven't started to grow.   When a tree begins to wake up and break dormancy, it also produces a flush of new root growth, and if you've planted it while it was dormant this gets to happen in it's new permanent location - meaning all of the new and succulent white root hairs won't be damaged or disturbed.  This is the best time to plant a tree, in nature it's common to have some damage through the fall or winter, from animals, the cold or just the environment - and trees have adapted to recover in the spring with a flush of new growth.    When you plant a tree with an intact root system, the tree doesn't need to expend as energy to rebuild it, it can wake up and use it's stored carbohydrates to flush it's new year of growth in good health and should recover quickly from being dug out and replanted.   Having said that, there are things you can do that will help the tree grow, and things you can do that could be detrimental to it's survival. 

Planting the tree - sure just dig a hole and in goes the tree, right?   When I plant little spruce trees in the forest usually I'll walk around with a dibble bar and pail of trees, the act of planting the tree is fast - produce a hole, in goes the tree and and you close the hole. If the ground is soft use the heel of your boot.  This type of tree planting, like the type you might think of in reforestation is fast and simple. You're usually planting very small conifers, and usually plugs meaning they were grown in plug trays shaped like popsicles, popped out, wrapped up and kept cold until they can go into the field.  Usually a recently clear cut forrest.  Silviculture is the practice of growing and planting a forest of trees. So this I would say is one end of the spectrum, you can plant the tree in 20 seconds.  Even in this situation, location can be important, selecting near a stump or log that will provide shelter from the drying sun is important, the ones I plant shaded by some hazel always survive better.  And there's that, survival is a percentage.  Here these are trees planted where no one is going back to water them, you just plant lots and hope for the best.   Usually it works out, trees can be tough.    An apple tree is your back yard is a little different, you want to give is more care and attention and give it the best conditions to thrive.     So that hole should probably be more than a dibble bar, use a shovel or a spade.   Typically there's going to be turf, grass and it's tough - grass roots are few inches thick and you might have to jump on the shovel to cut through it.  I usually start around the perimeter, make it 2 or 3 feet wide.  Should the hole be square or round?  I think either is fine, but if you make the hole round, rough it up with your shovel by chopping into the sides - if you leave it perfectly smooth you can get a root bound effect, where a growing root may hit the side of your hole and even though it's in the ground, the path of least resistance is to glance off the hard packed edge of the hole and circle the perimeter.  This is common in potted plants, if they've been in the pot too long the roots over grow the container and will circle.   For a healthy root system, the mature tree should have most of it's roots grow outwards horizontally within the top couple feet of the surface and spread outward, not unlike it's branches, spreading past the crown of tree, and producing small feeder roots that will extend towards the surface, and these often are partially regenerated like the leaves of the tree through the seasons and years.  They intertwine with soil microorganisms and fungi to create a complex symbiotic relationship.  This happens across the soil subsurface.  Often roots can grow surprisingly wide, in research where roots are carefully excavated they can be found extended further from the base of the tree than it is tall.   Do the roots also grow down?  Sure they do, but mostly outwards.   Another function of the roots to anchor the tree, it's suggested that if you do have a stronger section of root it should be positioned on the side of the tree where the predominant winds come from.  This is more important for fruit trees with dwarfing rootstocks, which by definition have weaker root systems and often need more staking and support - or they can actually fall over with a large fruit load or high winds.   In the cold Canadian prairies, we like to use full sized Malus Baccata (Siberian Crabapple) rootstocks.  Our short growing season and cold winters require the most hardy trees, and a vigorous tree has the best chance of survival.  If you want a small tree, just prune it small.  Yearly pruning can easily manage the size of your fruit trees.  Dwarfing rootstocks that can at most produce a small tree are better for warmer climates and longer growing seasons.   We have some 15 year old apple trees here with very minimal pruning that are about 15 feet tall with a six inch calliper trunk.  How tall do you want your apple trees to grow?  Tall enough you can pick them without a ladder is a nice height, and completely manageable in our climate on full sized rootstock.   Want to do zero pruning? Sure a full sized apple tree can get up to about 30 feet tall if you decide to just never prune it, maybe that's ideal for a shelter belt or an out of the way location for wildlife. Deer and birds can eat the apples as they fall.  If it's in your back yard or small home orchard you can prune the trees to any size or shape you like, even consider the step over espalier or Russian creeping form, where you can literally step over the tree.  An advantage to this type of training is the tree is close to the ground where it can be completely covered by a protective layer of snow during the coldest part of the winter, and may be one good way to zone push - or grow varieties that otherwise shouldn't be able to grow here.  

So you'v got a hole - the basics here are to plant the tree to the same depth it was grown at, and if it's a grafted tree that will mean you want to keep the graft union a few inches above the ground. Back fill, water well, then add some mulch.  Graft unions in case you aren't familiar - are distinguished by a lump near the base of the trunk where 2 varieties have grown together, sometimes the bark will be a slightly different color, or otherwise an irregular bump will be visible.  Graft unions became less noticeable as the tree ages, but just in case it was'n intuitive - trees widen as they age, and they only lengthen from the growing tips, the union will 4" above the ground today will still be that high above the ground 20 years from now.   Well, that is unless the soil is built up. Which we actually recommend, the take away is just don't cover the graft union up so that the top variety grows roots into the soil. One of the reasons we use a root stock is because that variety has hardier roots.  Protecting the graft union can be important, especially in the winter when the trees is young, because it's one of the most sensitive areas to cold damage - and this can be done with a tree guard, lots of snow, and mulch.    

Should I amend the soil?  What about putting the sod into the hole, adding compost, and what about fertilizer?    There's variety opinions on these, and the right answer might just depend on your soil.   If you have pure sandy soil, and water is going to run right through it there's 2 things you want to consider here - the first one is it would probably be helpful to mix some organic mater / compost / potting soil into the native soil when you backfill.  The other thing you'll want to do is spread compost and wood chip on the soil surface around the tree to build organic mater and enrich the soil from above.   Could you till in manure or peat moss, compost into the area before planting?  Yes, if you want to till the area - some people really like to till.  If you do the manure, it needs like to decompose before planting. Better to plan far ahead and do this the year before.   In general large volume soil amendment will have better results if you do them ahead of time.  If you're planning an orchard and you're going to prepare the ground, it's recommended to start the year before.   If your soil is heavy clay, you should consider planting the tree very shallow - even on top of the existing soil level in a mound.  This has the benefit of allowing you to plant in a rich compost, creating surface drainage away from the tree, and avoiding the tree from drowning in saturated clay - the mound will let the young roots have access to oxygen and they'll grow into the surrounding soil.   In this situation you should also consider adding organic material, like compose and wood chips to the area around the tree to gradually build the soil from above.  Compost is pure decomposed organic material, rich in nutrients. Your clay soil will also have a percentage of organic material, the main concern with it is drainage. 

What's mulch, why do we like it?  My favorite mulch is wood chips, which can be found with a bit of searching - either you get them by the bag at a hardware store or garden center, a landscaper, sometimes land fills have them, or maybe a neighbour with a wood chipper.  Tree removal companies usually have them by the truck loads and make them available by the yard, and if you're into gardening or landscaping your yard they're kind of awesome, and they eventually break down into a rich compost.   But you can also use leaves, bark, twigs, any type of organic material really.  Compost can be excellent mulch. Pile it around the tree in a donut shape, don't mound it against the trunk (don't volcano mulch) but also make it deeper than you might expect you need, go 6-8 inches deep.  This can be something like a couple of 5 gallon pails of wood chips for a tree.  Mulch is awesome because it retains soil moisture (read you don't need to water as often) is critical in the first year or two to keep your tree alive and healthy.  It also moderates soil temperature, and maybe most importantly protects the root system in the winter.  The difference between mulch and not enough mulch in a Canadian winter can be the survival of your tree.  The roots of a tree, while it maybe -40C above the snow, may only experience -5C under the insulation of the snow and ground.  Fruit trees need this layer of protection for their roots, they just aren't cold hardy like the trunk and branches.  This is also the reason you can't leave a most potted trees exposed outdoors here in the winter, the cold temperatures will kill the roots.  Potted trees overwintered in cold climates need to be covered up significantly, and even better kept below the ground.  This is one of the reasons we choose to grow trees in nursery beds instead of in pots, it's easier to take care of them through the winter.

Do I need a stake? What about the stake?  Well maybe you do. If you want to be cautious go ahead and stake your tree for the first year. In our experience a one year whip, which is mostly what we offer - usually can get by without a stake.  It depends on your location, if it's fairly exposed and windy I would suggest using one.  If you do choose to stake your tree, a relatively thin stake made from 1" wood or bamboo is sufficient for small trees. Your concern here is the tree breaking at the graft union, and there's also this phenomenon during spring thaw where a layer of melt water can accumulate as ice on the snow, and as the snow melts and the ice moves it can be frozen to the tree, and that can damage it. How common is that? It depends on the year likely, how the spring goes, and how much snow you get.   When you tied the tree to your stake make sure not to use a thin wire or anything that could cut into the tree as it moves in the wind.  Green nursery tie tape, strips of rubber, any commercially available tree ties - there's cool ones that look like a rubber chain and link together, or some soft rope will all work.  If you're going to use a large stake like a fence post, which would usually be reserved for a larger tree but maybe that's what you've got - put in into the hole before the tree so you don't damage the roots with it.   A bamboo stake is pretty minimal and can just be pushed into the ground. 

Tree guards, do I need one?  If you've ever noticed a rabbit in your neighbourhood, yes.  Generally they're a good recommendation for young trees, they protect against herbivory (read your tree bark is a rabbit's or gopher's lunch), and maybe more importantly they protect from winter sun scald.    We're talking about the white plastic type that springy and can be uncoiled to wrap around the tree.  There's also simple fabric ones, which work more for the winter sun protection, and then there's all kinds of options including wire mesh, consider a park might have a tall chicken wire cylinder around their trees to protect them from wildlife.  If you have animal pressure, a tree guard to prevent girdling can be important. Animals like small rodents can often chew away bark around the circumference of the tree at the soil line, from under the snow and this will be fatal to your tree. It can sometimes be triaged with bridge grafting, but for sure it's better to take precautions.  This is one reason you don't want to mound your mulch up against the tree trunk, it invites rodents up to the tree.    The other reason for a tree guard is winter sunscald, and if you haven't heard of that it's possibly the biggest cause of winter kill in young trees.    Unintuitively this happens after the coldest part of the winter is past, going into spring as the weather warms up.   On the sunny days where the air temperature is above zero, the sun may warm up the sun facing side of the tree to 20C, and after some time this can begin to bring part of tree out of dormancy, and sap begins to flow, the tree tissues begin to swell with water and the tree is all happy that spring is here.  Then it freezes hard at night, cold enough that the sap freezes, even though it's sugar content put it's freezing point below 0C. This can cause the now hydrated cambium cells to explode.  Maybe it's a small amount of damage each time, compounded across several days with just the right temperature and sunshine.  The result is the south west side of the trunk (this is also called southwest injury) is damaged beyond repair, and can be seen as discolored patches going into april and may.  They turn black and the cambium tissue just below the bark is dark brown, dead.  It concentrates in patterns along the trunk and it's branch collars.  Interestingly, usually the actual branches are unaffected.   In our first year at our orchard, about a third of the apple and plum trees we planted suffered this.  A tree guard reflects that light / heat and keeps the tree dormant.  So does paint.  If you use the guard, take it off in May then put it back on in October because during the summer it will trap moisture against the tree and may cause injury.   We've left tree guards on and forgotten about them for years and the trees were ok, but there's a risk if you do.   If you have quite a few young fruit trees, consider using dilute white latex paint over the trunk.  It's an aesthetic choice, and a balance of practicality - it protects the tree for years with one application, and in my opinion looks good.   Another consideration is to incorporate some shade into your yard or garden layout, the winter sun is at a very low angle compared to the summer, so something nearby the tree on the south side, I've even heard of wooden planks being used for this purpose, will shade the tree in the winter but not in the summer.  For our orchard at the nursery we have a food forest, and it's a dense planting so the trees help shelter each other from the sun.  And we paint all the trunk white with a white wash 50% diluted interior latex paint.  This approach with the paint is also used is southern climates to protect the tree from the sun in the summer.   If you're pruning a larger tree and expose lateral branches which were previously kept shaded, consider using some dilute paint on the tops of those branches - otherwise you might find the sun has burn them just like a day at the beach without sunblock, and the by the end of the season the bark is peeling away.  The tissues of the tree will acclimate to the sun over time, and branches will grow in to shade the tree. 

Do I need to water the tree? What if I forget to water it?  Sufficient watering for a newly planted tree is essential for it's survival.  The root system is tiny compared to where will end up, it has 1% the volume it will be.  If it rains once a week all spring and summer, then water less often.   If you've planted the tree in a swamp, maybe you're ok unless you get a drought.  In average conditions, you'll want to water the tree regularly through the first part of the growing season in May through July, and then slow down or stop watering in August.  There's a good reason for this, you actually want the tree to slow down producing new growth and have enough time for this year's growth to lignify - to harden off and become resilient to the change in seasons and fall frosts.   Give the tree an inch of water per week through the summer, combined with rainfall and taking general weather into consideration.   In August if the tree looks healthy stop watering, or only water if there's an unseasonal heat wave.  If the leaves look wilted or the tree appears to be under water stress, then water.    After the leaf drop and before the ground freezes in October / November, give the tree a deep watering to help keep it hydrated through to the spring and also saturated ground will better protect the root system. 

 

 

 

 

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