Greetings from a newbie! In the spring I am planning to replace two of my apple trees with other varieties, and I'm wondering if I need to be concerned with "apple replant problem." I live in a Portland suburb and have 11 apple trees, all on dwarfing rootstock. The ones I want to replace are approximately 6 years old, and I was planning on putting the new trees in the exact same location where the old ones were. I've done a little Googling of the topic and most of what I find are discussions of the problem in large-scale orchard situations, with recommendations of soil fumigation with chemicals I've never heard of.
Is this anything I should be concerned about, and if so, what might I do to avoid or alleviate the problem without the use of noxious chemicals?
Thanks in advance for any suggestions!
Ken
Welcome, Ken ...I’ll take a shot. I’ve hand dug …sixty year old apple trees, removing only the roots around the immediate rootball & hole and have never had anything that appeared to be a “replant problem†when planting an apple tree within the same hole or within the root zone of the orgional tree. If you were to remove as much of the 'six year old tree/s' as necessary to ‘dig a new hole’ for any tree, I think you’d be fine. …just pull out any obvious pieces of root and don’t leave them to rot in the hole…
-- But …as a grafter, and specifically a ‘Top-working grafter,’ six year old apples (with their established root structure) should be perfect candidates for grafting over to another, if not multiple varieties 
And it’s not supper-difficult. If they’re diseased or severely damaged low on the trunk, I’d likely take them out, too. But if you’re simply not happy with the varieties …and they’re healthy well-branched trees… I wouldn’t waste them.
If you’re interested, check out the following … you’d likely enjoy both the “beginners class,†where we teach ‘bench grafting’ onto a small rootstock, with around a dozen apple varieties to choose from - and you walk out with a tree! Or more specifically, the “intermediate†class (which I generally lead), dealing with “Top-working†an existing fruit tree. Here’s the info:
Grafting Workshops: Saturday, February 19, 2011 - 8:45 AM at the Clackamas Community College
Two beginning classes and one intermediate class. Registration is through the college. The classes reach capacity quickly, so registration the morning of the class is unlikely. First class begins at 8:45 AM. You will go home with a new tree that you grafted.
I agree with Viron that grafting over to new varieties would be a good approach, particularly on such relatively young trees.
However if you definitely want to dig out the old trees and replace them entirely then I think you do need to be careful about the re-plant issue. All the commercial nurserymen I know take it very seriously. I would not plant any fruit tree in the same hole as a previous one. However it is less of an issue if you are re-planting, say, a plum in an apple tree hole etc.
There is also a relatively simple way to resolve it, if you really do want the new tree to go in exactly the same location - dig out the old hole as big as you can manage, remove all the soil, and then re-fill it with fresh soil from somewhere else in your garden. Happy digging!
Ken,
I agree with Viron why not just graft?
But if the rootstock is what you want to change or you just want to dig the trees up and replant that is OK too. The only time to be concerned about replanting a tree is if there were disease or insect problems. I do NOT recommend removing a lot of soil and replacing it with different dirt. This doesn't mean you cant do some amendments.
Here is the rationale for not replacing dirt: The roots will treat the edge of the changed dirt like pot and not extend out into the rest of the soil. I know this sounds far fetched, but it has been proven over and over.
Randy ac7nj
Yamhill County Master Gardener
Copied by Viron; From corvinae
Joined: Sun Jan 23, 2011 11:22 am
Posts: 2
Location: Clackamas County, OR:
safe place to re-plant peach?
Hello, I'm new to the list.
I murdered 2 lovely peach trees by not spraying them enough/correctly and they succumbed to peach leaf curl. That got my attention about how difficult it is to control leaf curl.
I'd like to replace the trees and try again. IS IT SAFE to plant new trees in the same location? (the dead trees have been removed).
Viron,
Peach leaf curl is a fungus that has spores and generally rest on the trees them selves. Soil infection according to my research is NOT a consideration. Here is a nice site to read if you like [url:ub39j9vu]http://www.umass.edu/fruitadvisor/factsheets/leaf_curl_sheet.htm[/url:ub39j9vu]
Randy ac7nj
Yamhill County Master Gardener
Thanks to Viron et al for the helpful replies. I hadn't seriously considered the grafting option, probably because I've never done any grafting. The trees I want to replace are fairly large and I guess I was thinking it would be an awful lot of work to replace all the bearing branches with those skinny little scions I seem to recall from books on grafting. But maybe there's a way around that? I'm sure I'll find the answer when I sign up for the class that Viron recommended!
Thanks again to all who replied.
Ken
Another way to restate Randy and Viron's point of view: the tree expends up to 20% of its energy exuding liquids that will encourage healthy microorganisms to its roots, and setting up a soil food web underground. If you use pesticides or synthetic strong fertilizers, you kill that. If you remove the soil, you might be removing possible diseases, but you will surely be removing all of the positive soil microbiology as well. I think this is why the test that Randy is talking about is true. The bacteria that will naturally grow at the surface are different from the bacteria, etc. that will grow at mid level and at depth, thereby creating the pot effect that Randy was talking about.
John S
PDX OR
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Marsha H
Viron
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