When to Plant
Technically we can plant trees at any time throughout the year but like all things in life, there are pros and cons for each. In my personal opinion, the best time of year is going to be when there is the highest likelihood of success with the least amount of effort. Early-mid spring is the time of year that corresponds with those goals. You are looking for when the trees buds are still small and unopened with temperatures that are cool but warming up. The semi-constant rain also ensures good soil moisture without any extra effort on my part/ pocket book. This is also the only time of year that we recommend planting bare- root trees.
Fall is still a good time of the year but soil moisture will be lower so they will require more faithful watering and are in greater danger of being affected by any early freeze.
Summer is an ok time to plant trees but is the one that will require the highest maintenance. The new trees will need to be deep watered every 3-5 days. Even then they will be more prone to planting stress as the heat will be harder for them to handle with the minimal root system necessitated by most types of purchasable “formats”.
Winter is actually an ok time to plant trees but comes with such major drawbacks that it isn’t usually attempted. The main one of these being that the ground is frozen and trying to dig a hole in frozen ground is awful. The other one being that these trees will be highly susceptible to a mid-winter warm spell which could cause bud swelling and then freezing when the temperature drops back below 32 degrees.
What “Format” Is the Tree In
I know this is a “techie” term but it seems to be the best one that fits. There are three standard “formats” that we can buy trees in: containerized, B&B (Balled and Burlapped) and bare- root. We could technically add tree-spaded but that is not very commonly done by us standard home owners.
Containerized plants have been grown in a tree farm or nursery and then either transplanted into pots on sight or been planted into pots once they were received by a commercial nursery or store. These can come in a wide variety of sizes that will be labeled by either the size of the pot or the size of the diameter of the trunk of the tree. Containerized plants will be in the middle of the pack when it comes to pricing between B&B and bare-root. The major concern when buying a containerized tree is buying a tree that is either has circling roots or is already completely root bound.
Balled and Burlapped trees have a higher survival rate than either the bare-root or containerized plants but they come with some drawbacks. They are Heavy and yet they should not be handled too roughly or you could cause the root ball to break up, aka you just lost the root advantage you just paid good money for. Their other major negatives are a higher price and that you have to dig your hole that much bigger to fit it into the ground.
Bare- root plants will generally be the cheapest per plant and have the added advantages of needing the smallest hole and being incredibly light. Their main disadvantages are that you have to be careful to not let their roots dry out at any time during transition and have a limited window for purchasing and planting aka early spring.
Find the Collar
Finding and planting the collar of your tree at the correct height is one of the most important keys to ensuring your trees later success. The root collar is where the stem (trunk) of your tree starts to widen this is also where it meets the root system. You should remove all dirt/ mulch on the top of the root ball until you can just see the tops of the trees lateral roots. This root collar absolutely ABSOLUTELY must be visible when you are done planting!!! I cannot stress this enough! It is extremely common to the point of almost being a guarantee that the level of soil in containerized or balled and burlapped trees is too high. It has been found that root collars can be buried anywhere from 1-10 inches too deep in their pots or under the burlap. You will need to remove all the dirt that is above the collar and then make sure you do not cover it up throughout the process of planting.
Digging the Hole
Don’t just dig, think about what your goal is. It is to make a home for your tree that will encourage rapid root establishment. Most tree roots will be found in the top 10-18 inches of soil so we want to keep that in mind when we are digging. An ideal hole is one that looks like a wide, shallow bowl. When you are finished, the top should be 3-4 times wider than the root ball tapering to a width of about 2 times wider at the base. This will encourage the new and very tender tree roots to start spreading out and away from the trunk.
If the sides of your hole get that smooth glazed look when you are done shoveling it is important to roughen them up. Glazed sides can act like a pot, causing roots that reach the sides to turn instead of going straight through.
This may seem obvious (especially if you hate digging as much as I do!) but try not to dig the hole any deeper than the tree needs. If the soil that your tree is set on gets roughened up your tree can settle and sink. Then all your effort at finding the collar height will be in vain.
Moving the Tree to Its New Home/ Removing all Packaging
Balled and burlapped trees
I have found that it is easier to keep the root ball of your tree undamaged if you carefully lower the tree into the hole with all its “packaging” intact. Once in the hole remove all twine or string (even if you were told it is biodegradable) as well as as much of the burlap or wire basket if present. This will take extra time but it is worth the investment. Burlap that is left to reach the surface can even act as a moisture wick, aka soak up the water in the root ball and allow it to evaporate up through the fabric. Use wire cutters to cut any baskets into pieces that you are able to pull out. Digging a wide hole will come in handy here as it will give you room to maneuver your tools. It is not a critical issue if you have to leave a bit of wire basket or burlap under the very bottom of the tree. You might need to place a ring of backfill soil around the base of the tree to keep it from tipping over.
Bare- root trees
When placing them in the hole make sure its root system is spread out across a flat bottomed hole or on a shallow mound of dirt in the bottom. Do not force a bare-root trees roots into a hole by making bending them around the sides. It is actually better to cut the roots with a clean/ sharp set of pruners than to start them circling around a hole.
These need to have their entire container removed. Even if the container says it is biodegradable. Most bio containers will still take too long to degrade and can cause root turning or soil interface complications. Lay the tree on its side and carefully work the container off. If there are any circling roots this is when you need to shave off the outer 1-1/2 inches off the sides to correct their direction. Carefully lower the tree into center of the hole and place a ring of your backfill soil around the base to stabilize it in that position so that it won’t move around while you finish backfilling.
Never carry or attempt to move trees by their trunks, this can cause separation of the trunk from the roots system with predictable results. Dropping or rough handling of the root ball can have the same results. This is a good time to double check that the height of the root collar is just above the height of the hole. Whether you are planting a balled and burlapped tree or one in a container it is best to remove as much of the packaging as you possibly can without disturbing too much of the root ball.
Double check that your root collar is level with the top of the hole or even ½ inch – 1 inch above before you start to backfill (aka, putting the dirt back in the hole). It is better to be a little on the high side than too low.
Simply use the soil you dug out of the hole in the first place. We are often tempted to put “good” soil in the hole but this will cause interface complications that can result in consistent drought, drowning or girdling that will eventually kill your tree. This also applies to any other amendments or fertilizers. Fertilizers are too harsh to be put directly into the hole with tree roots and can also kill your tree.
It is ok to remove any large rocks we encountered while digging. Break up any large soil clumps but do not pulverize it to look like potting soil. Do not over-pack the soil into the hole, it is best to simply allow it to settle naturally when you water the tree. If the soil level sinks you can add some more of the backfill to level it off. The top of the root ball should remain uncovered when you are done. This can be hard to those of us who like things to “match” but none of the backfill soil should be placed on top of the root ball.
Watering- This will depend on your area. A sandy soil will need to be watered more frequently for longer amounts of time than one that has a lot of clay. A good rule of thumb is to thoroughly water new trees every 2-4 days when it is just getting established and then every 7-10 days when there is not enough rain for the first 2-3 years.
Pruning- Anything dead or broken can be removed at the time it is discovered but it is best to wait until after the first year or two before pruning any live branches. Newly planted trees are already stressed and lack an established root system so any energy it uses for wound repair or new growth will come from what it has stored in its trunk/ main branches instead of towards root development.
Fertilizing- Can be done in moderation once the tree is already planted and preferably once it has already started to become established.
Mulching – Should absolutely be placed 2-4 inches thick to cover the entire width of the planting hole. Water proof weed fabric should not be used under mulch that covers tree roots. Then any irrigation water will get the mulch wet but never reach the roots. It is preferable that no mulch cover the root ball for the first year or two the tree is in the ground and never (for the life of the tree) allowed to touch the trunk of your trees. Mulch volcanoes are a fad of the past that is still killing trees today.
Trunk Protection – New trees have thin bark that will be prone to mechanical injury and winter freezing. You can used any lightweight fabric to wrap trunks to protect them throughout the winter but it is important to remember to remove it every spring once freezing temperatures are past.
Staking – Most staking does more harm than good. Wires can cause mechanical damage as they rub up and down and will girdle the trunk when left. If you live in a high wind area it is best to use some form of soft/ flexible material that can hold the trunk without causing damage. Staking should be removed after only a year or two. A tree that is supported for too long will not develop the reaction wood that is needed to hold itself up.
Trees are an investment of time and money. Taking the time to properly research what kind of tree you want and putting it in correctly will ensure that your investment pays the dividends you are looking for. I have listed some wonderful resources below that go into even more detail and have excellent pictures that show ideal planting depth and what root collars look like. Happy Planting!