I'm not a regular participant of this forum as my profession exclusively revolves around growing and caring for fruit trees, but I thought this would be of particular interest to participants of the tree forum.

I found this while looking for information about the need to remove wire baskets when transplanting large nursery trees. There are some things here that contradict the accepted methods of planting 20 years ago when I was a hort student- some of which is methodology I already figured out but some that contradicts how I've been planting stock.

I thought it might be of interest to anyone who sometimes transplants trees and might be a starting point for a discussion on the subject. It is the first I've read of how adding amendments to back fill can be useful with specific guidelines, and seems to be an evolution from and even a contradiction of Carl Whitcomb's original research on the subject. I probably point this out because this is one area where the proscribed methodology is close to my current technique.

There's a lot of concern about girdling roots which don't seem to be a big problem with the fruit trees I manage. I manage a lot of very old apple trees that have circling roots that I suspect merge tissue with the trunks they press against therefore preventing actual girdling.

It is also recommended that trees be planted so the graft unions always be facing north for reasons I don't understand. I always plant trees so the part of the tree with best branch development faces north.

The proscribed shape of planting holes here is also interesting where it's recommended having the holes slope upwards immediately beyond the root ball to guide lower roots upward to airier and presumably warmer soil. I would be concerned that this might lead to poor anchorage in compacted soil but would be reluctant to go against research.

Anyway, I hope some of you enjoy this and look forward to any response.

I don't disagree with the idea of always creating saucer shaped planting holes but I do find it counter intuitive (scientific reality often is). I should think that in compacted soils a large cylindrical hole would encourage deeper rooting and better anchorage. I've found that trees often blow over in heavily compacted soil that have been broken up to provide generous planting holes and I'd like some reassurance that the saucer shaped hole is the best way to manage this problem.

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i do this .. because .. for the most part .. we are dealing with homeowners .. rather than professionals ...

the average homeowner.. has a tendency to overdo things in the garden..

if a light application of fertilizer is suggested.. they think that 3 bags will be better ..

if told to amend no more than 10%.. they figure 50% is better ....

there is no reason a tree ... needs anything other than native soil ... but for ... severe clay soil.. and then the amending is due to drainage issue.. not making a comfy bed for the roots ...

it is better to err towards nothing .. than to explain how to apply 10%

ken

There are very few legit reasons for amending a planting hole. I plant straight into my heavy clay without any reservations at all. Areas that might be poorly drained should be dealt with in other means besides amendments.

Of course, it's worth mentioning that large planting beds can be amended and improved to our hearts' content. Just not when planting hole-by-hole.

It is really important to avoid putting mulch directly over the root ball and certainly up against the trunk of a tree. However, a layer of mulch is one of the most beneficial things you can provide for newly planted trees...directly outside of that root ball. Mulch creates an environment within the soil system that will encourage the development of new roots outside that root ball. THAT'S where you want to concentrate your efforts...those roots will begin leaving the confines of the original root mass within an extremely short time. You'll be mulching the new root ZONE, not the root ball.

Thanks for bringing this link to our attention. It's a good one.

Every year I install trees in many different sites and in poor soils I believe it is beneficial to blend in some well composted OM in at least the top few inches of soil (always well beyond the current root ball). I simply try to mimic the natural structure of forest soil with it's parfait of textures running from rotting leaves, to a layer of almost pure spongy humus segueing to the native mineral soil. This has long been my technique- at least in very poor soils and now I feel vindicated by current research. Of course, I've also done some things that current research begs me to correct and as soon as I have a full understanding I will stand corrected.

I will change my methods according to research where it makes sense to me to do so and that's part of why I posted this- to get some input from other tree intimates. Just because someone has been doing something with success for a long time doesn't mean it's the best way to do it.

If anyone can find any specific research that must have been the basis for the guideline about installing trees in a saucer shaped hole please lead me to it.

Thank you all.

As for the shallow bowl shaped hole, I agree with the recommendation but question parts of their explanation. Root growth direction (and root system development) is determined by a number factors including genetics and drainage. The shape of hole (not counting its effect on drainage) should not, and normally would not, direct the root growth towards the surface.

While I like the Colorado State document, overall, I wouldn't put too much weight into just that one source for areas where their recommendations vary from the normally recommended methods (there's probably not much of that though). And, I certainly wouldn't depend solely on the document for overall methods, because it leaves out a LOT of stuff. I like it mostly because it explains some parts of the process better than most brief sources, but I don't think it was meant to really dig very deeply into the science behind the recommendation.

"The recommendations to not mulch over the root ball comes from research work by Dr. Ed Gilman at the University of Florida (his website in tree planting is found at http://hort.ifas.ufl.edu/woody/planting.shtml). He has presented these finding a couple of time at the International Society of Arboriculture Annual Meetings and folks seem to be on board with it.

Until his work came out, the GardenNotes advised folks to mulch over the root ball (with the thought that it will help stabilize the soil moisture, reducing surface evaporation. I made the change a couple of years ago to not mulch over the root ball, but rather just over the backfill based on his work. In his research, he found no growth benefit of the mulch over the root ball, but rather just mulching over the backfill and beyond. Depending on the type of mulch used, it can intercept some of the moisture in a rain or irrigation event. If the rain event is minimal (as would be typical of Colorado summer storms), the soil below the mulch could remain dry. I�ve looked at this closely under Colorado conditions and he is correct, we often only moisten the wood chip mulch with little getting into the surface soil with a typical Colorado storm. If your typical summer storms are heavy downpours that soak the soil deeply, it would be totally different situation.

In his research, non-established recently planted tree pulls all available moisture from the root ball so quickly what surface evaporation from the root ball is insignificant. (I was surprised with the findings, since I generally think of mulch as a way to reduce surface evaporation and save on water needs. But is makes perfect sense when I look carefully at the data. Water for the newly planted tree is coming from the root ball, not the backfill soil.

The saucer shaped planting hole comes from Principles and Practices of Planting Trees and Shrubs by Gary W. Watson and E.B. Hemelick (ISBN 1-881956-18-0). This is the ISA manual on tree planting. Folks have traditionally dug the hole with vertical walls. If the soil is compacted and clayey (and most Colorado soil are clayey with compaction), the roots begin to circle the planting hole when they CAN NOT penetrate the site soil due to low soil oxygen. This leads to trunk girdling roots several years down the road as the trunk gets to a significant size.

Root spread following the path of low resistance. With the sauce shape, WHEN the roots CAN NOT penetrate the site soil due to compaction (low soil oxygen) the root will follow the texture gradient of the saucer UP and OUT rather than circling the planting hole. As it come up and out, the oxygen levels will increase to a point where the roots can penetrate the compacted site soil and continue outward growth.

To help the tree anchor, it sits on un-dug soils. IF the bottom of the root ball is slightly curved, firm soil around the base of the root ball to stabilize it before backfilling the hole. With this planting methods, the tree does not rock in loose soil but rather sits firm on the solid bottom. The trick is to rest on the root ball on the solid bottom rather than loose soil in the bottom of the planting hole allowing the tree to rock in the wind."

David Whiting

Extension Consumer Horticulture Specialist

Department of Horticulture & LA

Colorado State University

If you have a rootball that is one foot in diameter placed into a three foot diamter hole, the area of the rootball represents one half of one foot squared times pi divided by one half of three foot squared times pi which comes out to approximately .75 divided by 6.75, the area of the entire hole. Then, you take a fraction of the .75 which represents the area not mulched divided by 6.75, and you get a very tiny area left unmulched.

The top of the root ball needs oxygen bad initially, especially as your initial waterings are frequent. It's actually kind of tricky when you think about it, planting roots period does not occur in nature, therefore one must think in unnatural terms why the idea of exposure around the top is sound, initially at the least.

Later, there are many reasons to not encourage root growth in this area by placing too much soil or mulch on the very top. That's just asking the tree to start growing circular roots in all but the best draining soils. When it rains, often the water doesn't make it down to the roots with mulch on top, so roots go seeking moisture up and around the trunk. It's going to rain wheter you water it or not.

If that don't make sense, be avised I'm not being paid at all for this opinion, an I'm hitting the kudzu tea and moonshine mix early and calling it a night. Join me sometime.

One of the possible problems of not mulching over the rootball is that, especially if the rootball is made of a different texture soil than the surrounding soil (which is most often the case), it's possible for it to dry out long before the surrounding soil. Mulching, by itself isn't necessarily going to fix this problem, but it certainly could help reduce the problem. I think mulching over the rootball is more important (at least until the tree becomes established) than mulching beyond that area. Also, as was mentioned earlier, if the correct type of mulch is used, it shouldn't cause the issues the author seem to be concerned about anyway.

When you got into that screaming fit with a fellow poster here recently, and gardenweb had to remove the entire thread, I knew you were a force to reckon with! May the force be with you Brandon, nanu nanu.

Abyways, Tennesse Brandon, go hug a tree and don't get too worked up, after all it's a very important subject, how to plant a tree. Me, I'm headed out back to the grove, gday mate.

That's when my laptop started smoking, I never did send yall the bill. Anyways, luckily it was covered ny the manufacturer.

I tell you what, let me get your address, I can send you somehing I've been growing, that will get you into the right frame of mind for the next paulownia thread. You know, it's just a matter of time...

I had them attach an industrial sized fan onto my computer, so I am prepared this time, though it's more of a lunktop now. Anywho, it's getting dark here now in Dallas, and I'm still sober, just like when I woke up.

Peace be Upon You
My Tree Hugging Friend,

"The One and Only Mackel"

It was about pawlies and was deleted.

To include on topic discussion, I have already started using the saucer approach and will from now on. It just makes too much sense. Of my casualties so far this year, I have noticed upon exumation the new roots extending from the potting soil into the earth have been in the top 6-8". However, I will keep putting a light layer around .5-1" of mulch over the rootball just away from the trunk. It HAS to help the already sandy rapidly draining black heat magnet soil stay cooler and wetter.

John

This is what I have observed between you and me, Brandon. You keep violating the ad hominem and the red herring rules during debate. I'll give you examples.

I said masking tape, not duct tape, big biodegradable difference, and I quoted a guy who is well known for transplanting successfully, one hundred plus year old trees.

It's not a crazy idea, it's not "off", it's an observation. By characterizing it like you did, you comitted an error of not only ad hominem, you did it by committing the second error, of distorting the obsevation itself.

You should be more careful when interpreting information from a fellow poster, but you also shouldn't go off on tangents, either, like you did in this thread about what the article didn't include. It didn't claim to be all comprehensive. And, it's irrelevent to your contention that the top of the root ball shouldn't be bare. That's committing the error of a red herring. Again, you are attacking the credibility, rather than the ideas, of the article. That's for the looney politics forum.

And if you do want to violate the established rules of scientific debate that have evolved over five thousand years of western civilization, you get the clown treatment from some people, like myself. Or open hostility, like from the guy who said something about your mom. Your mom should be mad at you, for allowing that to happen.

I believe I enjoy picking on you as much as you enjoy being right, so I'm not calling it a truce as of yet. We have the perfect partnership, you get to call me names, and I get to prove you right. Sounds like a deal.

Your Tree Higging Comrade,

"Mackel"

And since nobody gets hurt, unlike politics and what have you, it can be fun and games along the wayl. Now, Brandon, you are two pennies richer while I am still flat out broke, but sober.

"Mackel"

That's why I give extra credibility to Colorado article. Dissecting the article, there are clues at the very core of the nature of the struggle for a tree to get beyond the first few years.

The important issue in regards to a bare top root ball or a covered rootball, is for the roots to move as far away from the trunk as possible, not hang out with the trunk.

That's intuitively a waste of energy for the plant, very little moisture is around the trunk. It's ten percent of area in a three x hole. By encouraging the rapid movement of roots away from the trunk, almost guarantees you've committed no errors, and the tree will adjust rapidly, but a hard thing to objectively measure.

"No Charge for Service, No Charge for Plants",
Mackel in DFW

However, I doubt that any roots growing up into mulch would feel compelled to circle the tree - with no pot, they would head outward, I would think.

I do like the article and find it is quite good at explaining why they say what they do.

Karin L

Anyway, back to the issue of mulch over the root ball. To me the issue isn't the percentage of the entire planting hole that matters during the most critical first month or two of establishment. At that time I expect the vast majority of water being supplied to the tree comes from the roots in the rootball and not the first flush of growing tips going into the new soil. I could be wrong.

If the mulch applied was something like partially rotted arborist chips, it could supply a substantial reservoir of water, reducing the frequency of watering required far beyond the ability to minimize evaporation. Capillary pull should allow the tiny feeder roots that form on the mulch-soil interface to bring water from the chips to the tree. The author of the guide never provided me with a description of the mulch used in the study- but many organic mulches, including shredded wood and straw, do not hold much water. Shredded wood, in fact, has a strong tendency to mat up and repel water.

Another issue I think unresolved by the research is whether the insulation provided by mulch could be helpful when placed over the root ball. I don't know what species were used in the experiments but species vary widely in terms of temps roots function best in. Tropical species tend to like warmer soil, of course, but even amongst the fruit trees I grow in my nursery, there's quite a range of preference and none function as well once soil temps get into the 80's. This would throw a lot of untested variables into the whole idea of mulching, but mulch will always make temps cooler and more stable.

The trees I plant in the fall, when I do most of my installations of trees from my nursery, may well benefit from mulching the root balls by stabelizing soil temps when snowfall is inadequate to do so. This may protect roots near the surface from extreme cold and also help prevent the root ball from being pushed out of the soil by the freeze-thaw cycles common in areas with real winter.

I'm awaiting the results of similar experiments done in more northern areas, and also with trees adequately irrigated, before I change my methods.