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This article distills our years of tree planting experience to illustrate the differences between bare root and “balled and burlapped” (aka “B&B") tree planting techniques.
Bare Root Planting
Planting a tree in the "bare root" style is very literal. If you look at the below photo, you'll see the tree is all plant: no soil included in the root mass, only roots and the trunk.
Balled and Burlapped Planting (aka "B&B")
The alternative to bare root planting is the a "B&B tree," which stands for balled and burlapped. The roots are enclosed in a ball of soil with a burlap bag and wire basket around the ball. This is the more conventional approach to planting trees, but requires more digging (typically using heavy equipment) to move the trees due to the shear weight of the soil. Below is a photo of a red bud tree with the burlap and basket removed for planting.
Now that you can picture the difference between the two options, let's discuss the pros and cons of each.
Pros of Bare Root Planting
Can be planted by hand (very light)
Correct planting depth every time
Planted with a larger root mass intact
Quicker establishment of tree in relation to B&B
Cons of Bare Root Planting
Limit on available species of trees
Limit on size to 2” diameter trees
Pros of B&B Planting
No limit on trunk size of tree transplanted
No limit on available species of trees
Cons of B&B Planting
Heavy, often requiring equipment
Can be planted too deep
More expensive v. bare root
Majority of roots are removed
Root Growth an Important Consideration
The photos below highlight some of the important advantages and disadvantages of each planting method, focused particularly on differences in root growth between the two methods.
This photo above is the root system from a 3” caliper (trunk) swamp white oak that died the first year after transplant. Notice the tape around the trunk? That was the planting depth, you can see the root flare (where roots meet the trunk) was around 4 - 5” buried. Also notice how small the root system is (approximately 16” across) for a tree that large.
Compare the previous root system with the root system of the bare root tree below. This is a 2” sugar maple that was planted later that day. This root system is exceptionally wide and is not the norm, but it does show you just how many roots that swamp white oak that died above lost in the transplant process.
The last series of photos show the planting process when a B&B tree is planted too deep at the nursery. This series features a 5-6’ red bud I planted last spring on a playground. The first shot is of the root ball exposed and in the hole. The next one shows the trunk partially excavated to expose the root flare or proper planting height. The third photo has a 7-8” tall wire cutters in the shot to show you just how deep this tree was, the top of the wire cutters represents the original soil height and the bottom shows the final planting height.
I don't want to discourage people from buying B&B trees, but I do want to educate people on potential downfalls of getting a B&B tree and just “plopping” it in a hole. If you are contracting tree planting, make sure that the company knows how to plant trees correctly. Planting depth will dictate the long-term survivability and vitality of your tree.
I encourage people to consider bare root trees for their future planting projects. Either way you can’t go wrong planting trees, just make sure it's done correctly so the benefits will outlive us all.
Root Depth Affects Tree Health
Have you ever noticed a tree that looks like a pencil stuck in the ground while walking down the street? Here in Madison these trees are not hard to find, just try looking around next time you are out walking around.
But how many trees in the forest look like pencils stuck in the ground? None. They all have formidable root flares, where the trunk gets wide and meets the soil line. From that soil line to 12 inches down is where you will find most tree roots. The roots stay close to the surface in order to facilitate oxygen exchange essential for the tree’s survival.
Now imagine throwing a 6” layer of soil over the top of the forest floor, drastically cutting the oxygen supply to the trees. This is essentially what happens when we plant trees too deeply. Not only do we cut off most of the root system (to facilitate transport and planting) during the digging, now we stuck the tree in the ground too deep to get the necessary oxygen. Good luck arborlito, it's going to be tough!
The following discussion addresses planting depth and what to look for when you are doing it yourself or reviewing others' work. I have no problem looking over someone’s shoulder when we are talking about the future of our urban canopy. Please read this and other discussions on tree planting to get a full and comprehensive understanding of how to complete the task correctly. I’m trying to emphasize the most important step of planting here, planting depth.
How to Determine Proper Root Depth When Planting a Tree
When planting with b&b (balled and burlapped) or container sapling stock, the first step is to locate the root flare (where the trunk get wider, near the bottom). Don’t assume the root flare is just below the soil surface; I have found flares as deep as 8” below the soil line in some balled and burlaped trees! Once you locate the flare, dig your hole accordingly. Please remember not to dig too deep! If in doubt, err toward making the hole too shallow.
Carefully place the tree in the hole. We almost always remove the entire basket and burlap material, but this takes practice and care. If you want to remove everything, just make sure not to disturb the root ball, as you don’t want to loosen the soil around the roots. If the root ball is already pretty soft or loose, don’t take the basket off.
Now you are ready to skim off the excess soil to expose the root flare. I like to use tools intended for other purposes here. My favorite tool is hand pruners for peeling soil away, maybe because I always have one nearby. Be careful not to skim off the bark of the roots; you won’t kill the tree if you do some light damage, but no damage is, of course, ideal. If the soil is really hard and difficult to remove, try adding some water. Spraying SOME water might help loosen the soil a bit... at a minimum you will get really dirty and appear to be working hard!
Now you are ready to backfill the hole, making sure not to cover the flare with any soil or mulch. Put down a 2-4” layer of mulch around the tree, right up to the root flare. Continuous mulching, year after year, tends to build up around the trunk, so keep the flare clear of soil and mulch as time goes on.
Correct planting depth is crucial for long-term vitality and healthy trees. Planting trees too deeply leads to many issues, such as decreased growth rates, slower establishment after transplant, girdling roots, and ultimately a tree removal bill due to the shortened life span. Give your tree some flare, and your attention will be well rewarded. We think the tree looks better like that anyways!