It just dawned on me that I haven’t written yet about something that I’ve seen more and more — on virtually all my projects for the last several years, in fact — with new trees being planted in the landscape. It’s this:
Trees coming in from the growers these days (at least here on the East Coast) are often burlapped too deep to begin with. Cultivation practices in the growing nurseries have changed in the last several years; when tilling machinery runs up and down the rows, they flip loose soil toward the young trees’ bases, where it piles against their trunks. The soil is not raked or pulled away, unfortunately, and accumulates with each pass of the cultivating machinery.
When the trees are dug, they are burlapped and basketed to make handling easier, and the picking up and moving of the trees can squnch soil even more snugly around the trunks. By the time a tree reaches its site, it may have 4-8″ of soil above its root flare. If it has been in the nursery long enough, it may have started to grow a secondary root system into the extra soil; the root flare needs oxygen, and feeder roots that are too deep stress a tree.
This sugar maple was planted six inches too deep; an arborist excavated it one year later
It’s really important, in the planting process, to check the root flare and see that it is in the proper relation to actual finish grade, and if it isn’t, to pull away (gently, please — that bark may be tender!) the extra soil and expose the root flare. If that new little wiry root system has started to grow, it can be cleanly cut away at this point.
These days, I see lots of trees planted too deeply. I figure that it’s because the contractor assumes that the top of the root ball is the actual finish grade required by a tree. A stressed or ailing tree may sometimes be saved by the simple act of excavating that extra soil, and letting the root flare breathe. (When a young tree has been in the ground on site for a year or more and isn’t settling in well — has small leaves, looks chlorotic, has sparse foliage — the first thing to check is the root flare relationship to finish grade.)
The maple on the left was planted at the proper depth; the two maples on the right were buried
Arborists know about this problem; they’re often called to a site to find out why one or more new trees is doing poorly, and often they find that correcting the soil depth takes care of the issue. Some contractors know about this problem, but typically their laborers don’t, and it takes time and focus to teach them and have them make the correction with every tree. The landscape architect’s insistence on excavating that root flare can make the difference between a tree that settles in and thrives and one that struggles and develops more problems.
Ideally we could team with arborists, with nurseries, and with other landscape architects to get word to the growers that changes to their cultivation practices could eliminate the problem of trees showing up on site buried. In the meantime, making contractors aware of the issue — and being sure they address it during planting — can help insure the good health of our tree plantings, and the integrity of our designs.
Deborah Howe
Taking Place 
Thank you for this blog, I stumbled acrosss it and am finding it very useful !
I’m a new/first time home owner who went a little nuts planting trees in June of this year – I bought 7 Maples of different varieties, most are at least 15′ tall, burlapped. The business that I bought these trees from is a local one, the biggest in my area. They delivered the trees, I planted them. No one informed me that I should remove some of the soil at the top of the root ball to expose the root flare, so, I planted the trees using the existing top of the root ball as reference. The owner of this business came to look at my work afterwards, and said everything looked good (the trunks looked like a flag pole sticking out of the ground). Anyway, half of the trees are doing alright, the other half are looking sad (loosing leaves). I was looking on the internet to see if I did something wrong in my planting when I came across this site. Since reading this “Buried alive” segment, I’ve gone out and removed soil from the top of the root balls – all 7 trees needed at least 3-4 inches of soil removed. I feel good knowing that the root flare is now showing, but I’m worried that I may have exposed too much of the root flare (too many little roots showing at the base of a few of the trees).
Anyway, long story short, I was hoping you might be able to look at my root flares (took the images this evening) and tell me if you think it’s ok or if I have to add more soil again. This is stressing me out – these trees were expensive and I’m trying to do everything I can to make sure they ‘take’. I don’t want to be the new neighbor that plants dead things 😉
Thanks
P.S. I have since mentioned to this business that I removed soil to expose the root flare and they thought it wasn’t necessary (they looked at me as though I was nuts).
Bryan, thanks for your note. If the company that sold you the trees grew them, they’d know what you were talking about; my guess is that they bought them in, and so might be unfamiliar with the nursery liner planting and cultivation practices that make excavating a B&B root ball necessary.
From your photos it looks as if you did exactly the right thing (and it’s pretty clear, from the ruler marks, that you really needed to!). The little rootlets that you see at the base of a couple of those trees are evidence that those trees wanted to live; they are the beginning of a secondary set of roots put out the by tree into the added soil, in an attempt to survive the burial. Feeder roots — the smallest ones on a tree — exist mainly in the top 12″ (12-18″ on a bigger tree) of soil around a tree, where they have best access to water, nutrients, and oxygen. When soil or too much mulch is heaped over that zone, and stays there, the tree will attempt to put out a second set of roots to maintain its balance. It can take a long time for a tree to develop a big enough set of roots to sustain itself on that secondary system; its energy goes into doing that rather than into growing larger, and the effort really stresses the tree. Continued stress of this kind can kill a tree; first you’ll see signs of stress (smaller leaves, leaf drop, little twig extension), and over time — sometimes several years, sometimes only 2 or 3 years, depending on the species, health, and external conditions of the tree — the tree will decline and die.
With your excavation, that secondary system will be superfluous, and mainly an indication of the stress the tree experienced. It’s fine to take a sharp pair of clippers and to nip those little rootlets off at the trunk where they originate — you’re unlikely to harm it by doing that. Adding more soil isn’t necessary; you’ve done a nice job of excavating, and the trees look as if they can settle in and start to grow now.
At this time of year, plants are heading toward dormancy, and so you won’t see foliar evidence at this time that your trees are bouncing back — their energy will be focused on storing energy, rather than creating new photosynthetic material (ie, leaves). Come next spring, however, they should do considerably better, and show you that you’ve done the right thing for them.
Thank you very much for such a quick reply Deb – I really appreciate it !
[…] keeping it well away from that newly revealed root flare. In this post from Taking Place, and this one, I show the crown effects of buried root flares on pear trees and on sugar […]