Planting trouble: multiple trees in one hole

[I enjoyed Jeff’s Valentine story so much that I thought I’d stick to the theme of togetherness…for better or worse.]

A week or so ago a reader asked about the practice of planting three or four fruit trees in the same hole.  Having not heard of this before, I checked on the web and found many “how to” pages geared to home gardeners who either want a longer harvest of a particular fruit (early to late) or a mixture of different species.  Doesn’t it sound just great, especially for smaller urban yards?

One of these sites has these written instructions: “Plant each grouping of 3 or 4 trees in one hole at least 12 to 15 inches apart.”

Now, I’m sorry, but this is just asking for trouble down the road.  Readers of this blog know that root systems extend far past the drip line, and that roots from different trees are going to compete with one another.  You’ll end up with three unhappy trees, all jostling for space and resources, just like kids in the back seat during those long car rides.

But wait! you might say.  There’s research on high density tree planting, and it’s been shown to increase fruit yield on a per acre basis!

Yes, in fact there is a lot of planting density research on many different species of fruit trees.  What’s considered by researchers to be “high density” varies, but it rarely exceeds 2698 trees/acre (6666/ha for our international readers).  Optimal and sustainable levels of high density planting are also variable, as they depend on not only species but rootstock and the crown architecture; 1214/acre (3000/ha) might be a mid-range number.  This can be converted to a per-tree requirement of 36 sq. ft. or a 6’x6’ planting area.

How does this compare to the 12-15” recommendation given earlier?  If we’re generous and use the 15” recommendation, this translates to 6.25 sq. ft. per tree or 6970 trees/acre.  The 12” recommendation would lead to a whopping equivalent of 10,890 trees/acre.  (And no, it doesn’t matter if you’re using dwarfing rootstock or not; most of the higher densities in the literature are for dwarfing rootstocks.)

You don’t have to be a math whiz to see that these densities are totally out of line with reality.  Sure, you can probably keep overcrowded trees alive with lots of water and fertilizer, but they’ll be under enough chronic stress so that pests and disease might take hold, and fruit production will likely be poor.  And it’s about as far from a sustainable practice as you can get.

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Linda Chalker-Scott

Dr. Linda Chalker-Scott has a Ph.D. in Horticulture from Oregon State University and is an ISA certified arborist and an ASCA consulting arborist. She is WSU’s Extension Urban Horticulturist and a Professor in the Department of Horticulture, and holds two affiliate associate professor positions at University of Washington. She conducts research in applied plant and soil sciences, publishing the results in scientific articles and university Extension fact sheets. Linda also is the award-winning author of five books: the horticultural myth-busting The Informed Gardener (2008) and The Informed Gardener Blooms Again (2010) from the University of Washington Press and Sustainable Landscapes and Gardens: Good Science – Practical Application (2009) from GFG Publishing, Inc., and How Plants Work: The Science Behind the Amazing Things Plants Do from Timber Press (2015). Her latest effort is an update of Art Kruckeberg’s Gardening with Native Plants of the Pacific Northwest from UW Press (2019). In 2018 Linda was featured in a video series – The Science of Gardening – produced by The Great Courses. She also is one of the Garden Professors – a group of academic colleagues who educate and entertain through their blog and Facebook pages. Linda’s contribution to gardeners was recognized in 2017 by the Association for Garden Communicators as the first recipient of their Cynthia Westcott Scientific Writing Award. "The Garden Professors" Facebook page - www.facebook.com/TheGardenProfessors "The Garden Professors" Facebook group - www.facebook.com/groups/GardenProfessors Books: http://www.sustainablelandscapesandgardens.com

51 thoughts on “Planting trouble: multiple trees in one hole”

  1. Great topic and I was going to ask the question myself. The information I was given by TreePeople here in Southern California was to plant four trees one at each corner of a 4’x 4′ square. They also mentioned that the trees should all be of the same root stock. The idea behind this was that the root stocks would not compete but “grow together” and form one large plant. Any truth in this advice?

  2. John, it’s possible that you wouldn’t get so much root competition if they did graft, but you’ll still have 4 trees, each with a quadrant of their canopy directly interfering with its neighbors. And each will be making demands on the entire root system for water and nutrients. The high density research I looked into generally deals with monocultural plantings of fruit trees (same rootstock), and you just can’t plant trees that closely together and not have them interfere with one another. The literature is pretty definitive in that respect. (At least the 4’x4′ hole is bigger, but it still works out to a density of 2722 trees/acre, which is significantly higher than what’s recommended.)

  3. I would never plant multiple trees in one hole, but I’ve noticed nature does it all the time. Self seeding soft maples and mulberries are two examples from my own yard. The trunks seem to morph together making an interesting landscape plant.

  4. Jan, that can happen of course. But over time, most of the time, only the strongest survive and the others die off. It’s probably not a desired outcome for most gardeners.

  5. Brian, unfortunately the distances they recommend are too close for long-term tree health and fruit production. There are hundreds of studies on high-density planting and some of these are long-term. The science is pretty clear that planting trees too closely together will create problems after 5-7 years.

  6. I’m pretty sure the Sacramento County Master Gardeners have done this in their demonstration garden at Fair Oaks Horticultural Center. As far as I remember, it is all the same rootstock. Not that I’m an MG, but it all appears to working well (they’ve even got some neat examples of ladder-type grafting to unite the trees) with no problems. But perhaps that is because they’ve put the trees in large holes … and they are tended by MGs rather than the average homeowner.

  7. I once planted three peach trees in one hole. They stayed pretty balanced with a yearly dormant pruning. What put me off the practice was pest control. The early varieties were relatively pest free, but the late variety was too buggy to use.

  8. I’m glad I stumbled across this post. We were thinking of planting only 2 pear trees in one hole – no more than that. Would that still be too crowded?

  9. Judy, it depends on what you want. If you want small trees, growing them in the same hole will do that for you (since they will be competing for limited space, water and nutrients). Keep in mind that the half of each tree that grows into its neighbor is going to be more shaded and probably not very productive. You won’t double pear production as you would if you planted them apart.

  10. We don’t really care about the production – pears aren’t *that* good (!), but we needed a pollinizer. On the other hand, we really don’t want to do anything that will make the trees more disease/bug prone. hmmm. We’ll just do it the “old fashioned way” – and I’ve learned something to share with my clinic clients (I’m a MG). Thanks!

  11. Each tree would not get 12 inches, instead each group of 3 trees would get a 18 feet or 6 feet each which gives you the usual 1214 trees/acre.

  12. I don’t understand how you can reject an idea like this without first attempting it? Dave Wilson are long time growers and have had success with this method.

  13. Just freakin dig a 4′ diameter hole and toss 4 trees in it. Let us know how it turns out. Then we will have data on the East.

    I added a link that also advises against it without any evidence other than naysaying. Experiment. If it is really so bad you will know in 2-3 years and let us know.

    Remember roots are sluts…they will fuse with every other root and form a cohesive community underground AND competition is good to both control fruit tree size, produce more fruit per area/volume and produce fruit earlier in the life of a tree. Be nasty to your tree.

    Southern CA is different from most of the nation. Dry, hot, alkali and salty soil, low pest and disease, long season, mild winter, … how this effects BYOC needs to be studied in the east and the north.

  14. plant at outward angles, heavy summer pruning clearing out the middle area, keep height manageable. this is not a commercial orchard strategy nor is it designed to give max fruit/sqft, it’s a strategy to extend the growing season and to help with pollination for the backyard gardener. it takes MORE work.

  15. For the life of me – what’s the point in cramping, pruning and torturing two or three trees to live together . It’s as some of our posters here want to prove it can be done. Yes it can be done but two unhappy ( in the long or medium term) and unsightly (immediately) cramped up trees cannot be better than one nice healthy individual. I understand you may want pollination – make a deal with a neighbour to plant a sister tree or move house. We cause a lot of harm by not thinking of the future space needs of our trees in the urban landscape

  16. Sorry, but your analysis is based on the idea of crowding thousands of trees together. Every 15 inches, in all directions, for an entire acre. That’s not the idea. The thought is, you have one spot in your yard for cherry trees, and in that spot, you plant 3 different varieties of cherry tree, about 18″ apart. There are not MORE trees all around them, blocking light and taking water and nutrients. Just those 3 trees. Now you have better pollination, and 3 varieties to enjoy, and a longer harvest period. Lots of evidence this works great for the home orchard.

    1. I would accept your argument if it were supported by research. But there isn’t any for home gardens – only for production orchards and I’ve used that as supporting evidence for my post. And most people have landscapes with other trees, shrubs and groundcovers, all of which will compete for water and nutrients. There is no science behind this popular idea, so it’s not something this site will encourage.

      1. Hi guys, I was looking for info on the practice of “4-in-one-hole” as recommended by Dave Wilson. I planted 4 peach and nectarine trees in one hole in Hayward, CA 7 years ago.
        I followed all the advice offered on the Dave Wilson website, I built a 6 ft by 6 ft raised bed and filled it 10 inches high with mostly garden soil from my yard with some organic compost mixed in. Planted 4 trees of different varieties 24 inches apart. Fed and watered well for the first 5 years and had a professional fruit tree guy prune yearly and spray several times for peach leaf curl. He pruned the inner branches away, so the heavy branches bearing fruit pulled all the trees over to lay at odd angles to one side. While I was traveling my tenant was not keeping up with the feeding and he watered only once every 2 weeks, and 2 of the trees died, while one got super huge and was covered with brown-rotted fruit. The 4th tree has 60% dead limbs. It will probably die. Other trees planted at the same time in my yard and treated the same are doing spectacularly. This is fruit tree country.

        I don’t consider the experiment a success. I would like to ask Amy and the other folks who wrote in support of the practice, while questioning the good advice, one question…. Did you try it? What was the result? I am so happy I found this site and the great information offered by Linda. I hope she keeps it up…. thanks.

  17. Good to know someone tried this and posted the unhappy results. I have limited space in my new zone 8b/9a FL home. There are several citrus and stone fruits I want to plant; I thought to try this method because I can’t find “fruit salad” trees that combine the varieties I want. I would never attempt grafting them myself. Any thoughts on what I should do?

  18. I’m glad I found this site. I just contacted Trees of Antiquity and wanted to add 2 more trees to my order. I was thinking of doing the 3 in one tree thing as I saw on the Dave Wilson site. I think I will just stick with the tree I originally ordered. I have more than enough trees. Thanks for the info.

  19. I planted 4 groups of three-trees in one hole in Utah last spring (2017). I’ll keep y’all posted on how well this goes in the future. I planted different varieties of apple trees in one hole that are supposed to produce fruit at different times of the year so I could extend fruit production. Ditto for peaches, pears, and apricots. I plan to keep these trees heavily pruned to limit fruit production — just enough so the family can have fresh fruit. We’ll see what happens.

  20. I live in a very old house that has three different (large, mature) trees growing right in top of each other, and I’m worried they’re damaging each other. One seems sickly and I’m worried about the others. Is there anything I can do for them at this point?

  21. I recently purchased a house that has for citrus trees I believe lemon and orange.the problem is they are established and there are definitely more than one trunk coming out of the ground they look multiple. Is there any way to save these plants they are well-established

    1. They could be a single, multi-trunked tree…but even if they are multiples I would leave them in place if they appear to be well established. Just be aware that you will have to water them frequently and if you haven’t mulched them with arborist wood chips you should. That will give them the best shot at being productive.

  22. I live in Ohio and was thinking about planting orange trees in a green house. I was naturally excited to see the video on just pop multiple trees in a 2′ circle…. Ok that’s a bad ide a you have pointed that out enough,… So what is the closest I can plant 3 trees to each other ? Would a 10′ or 15′ diameter hole work, with the trees roughly 3′ to 5′ apart ? Granted there would be some overlap in the growth of the trees but some loss in productivity due to overlap might be fine to have some orange trees growing in the frozen north. Could this work ?

    1. The holes don’t need to be particularly wide – just enough to fit the root spread. And no deeper than the root mass.
      Generally trees are planted on 6′ to 10′ centers depending on their mature size. With orange trees I might shoot for 8′ centers. So that would translate to 4′ apart.

  23. Dr Chalker-Scott,

    You are obviously much more educated than many of us can hope to be. As someone in the healthcare industry, I also believe in evidence based practices.

    But there is always the curiosity to fail at something. And I’m not immune from it. I have a small backyard so I’m going to give it a shot. Any advice you could impart would be most helpful.

    Thanks

    1. I don’t think there’s anything wrong with experimenting as long as you aren’t causing damage to the environment or harming animal or human health. You will have to use much more water than normal and be prepared to have very little production on the interior of the planting mass. The competition for light, water and nutrients will be intense.

    2. I am from U K and I just started the same experiment here. I will have problem with too much water and chalky soil but I will post the results here probably next year
      those who are interested in multi grating on one tree should visit.: -Sam Van Aken, an art professor at Syracuse University, grafted the tree over nine years into something of biblical proportions. The “Tree of 40 Fruits” contains peaches, plums, nectarines and apricots, all of which are readily edible. Jeff Glor reports. Good luck to all including myself.

  24. Thanks for this article, Dr. Chalker-Scott. I recently bought a young (1.5- feet tall) Meyer lemon tree and realized afterward that it was actually two trees planted in the same pot. I recognize I need to separate them, but what is the best way to do so? Should I take a knife and cut the roots down the middle or try to painstakingly tease apart the roots? And does it matter if the soil is wet or dry when I do this? Many thanks in advance!

    1. If you can separate them and each has a decent root system, you will have two trees for the price of one! This is a common advantage to root washing trees before planting. You can always cut them if you can’t work them apart. I would plant each in a container and baby them along; they should do just fine with watering and mulching with a woody mulch (for their mycorrhizal partners).

  25. Hi Linda – would you please help me design an experiment to compare the 4 In one hole program with one tree in one hole with 4 different graphs? I am in North-central Montana building a subterranean greenhouse with 2 rooms one for Stone fruit (11 by 30 – planning on 5 holes with a zone 7 climate) and one room for 10 citrus and sub tropical plants (11 by 60 feet) which will never freeze – the green house will be 5 feet below ground And stand about 8 feet above the grown – so I will have about 13 ft of growing space – see Greenhouse in the Snow from NE – thanks so much – sincerely / bob

    1. Hi Bob –
      Sorry for the late reply – the pandemic has meant a lot more people asking gardening questions while they are stuck at home!
      To do a replicated experiment with trees you would need a lot more space than you have, and conditions in your greenhouse (which sounds very cool!) will be different than those in a field situation.
      You could potentially use smaller plants – maybe a small woody perennial herb like rosemary? – and grow those with 4 in one hole as the treatment and single holes as the control. You would need a minimum of 10 of each for a total of 20. You would need to supply identical amounts of water and fertilizer. The type of data to collect would take some time to devise depending on the plant you chose.

  26. Hi Dr. Chalker Scott, Few years ago I started to plant many fruit trees on the different spots on my back yard. 2 pear trees 15 or 20′ apart from each other one peach tree 10′ apart from pear trees. The way back at the other side of yard 2 fig trees 3 feet away from each other 4 persimmons trees 2 or 3′ apart from each other one mulberry , one pomegranate and one grapefruit 3 or 4′ apart from each other. None of them producing anything yet. They are 2, 3 years old. I want to pull my hair off after doing some research i don’t want to loose any of my trees because of survival competition. Is it too late to remove some of them to different location or let them to grove like that. I am not professional at this field. I rushed planting without doing research.

    The other thing is 2 of my persimmons trees growing from seeds I planted. Do I have any luck they can produce fruit.

    1. You don’t mention how you planted these trees. Did you remove all of the potting materials and spread out the roots? If so, they may need replanting anyway. (If they were bare root when you bought them it isn’t an issue). The pear and peach trees are fine. The others are too close. You should spread these ones out so they don’t interfere with one another. I would put them on 8′ centers.

      I don’t know about the ability of seed-grown persimmons to bear fruit, but theortically they should.

      Keep in mind that lack of water over the summer will reduce next year’s flowering and fruiting. If you don’t have decent root systems, they likely will not bear.

      1. Thank you for quick response. Some of my trees were bare root , some of them were inside the pot. I did not remove the potting materials at all. My main concern is if I try to change their location I might damage the root systems. They are at least 2 , 3 years old.

  27. Adding another twist to these multiple tree questions, I’ve looked at multiple video suggesting to plant a nitrogen producing tree, such as a black locust amongst your crowd of fruit trees? Any thought about that? I have a few mother nature grown black locust seedlings about 2 ft tall, I’m thinking of planting 2 fruit trees about 2′-3′ from each black locust – am I asking for future trouble? Oddly, on my property through nature – I have a mixture of black locust, black walnuts and cherry trees all crowed together in bundles. But the cherries are REALY large – 40′ tall – but produces no fruit. I’m thinking of planting pears and nectarines. Would greatly appreciate your thoughts and guidance.

    1. These recommendations are not based on science. Any tree, nitrogen fixing or otherwise, is going to compete for resources. Overplanting any site is going to result in less productivity for all plants.
      By the way, lack of fruiting is usually tied to deficient levels of water. Be sure to irrigate your trees well, especially during flower and fruit development.

  28. I came across this article as I’m trying to actually replace a lemon variety already growing in our yard with a better one. What we have was probably planted from seed, it’s been there before we moved in (17 years ago) or seeded itself more recently and we just never noticed. We are in San Diego, we have a hillside/canyon for a yard and because of the terrain we rarely went back there. I know our nextdoor neighbor had a habit of throwing old citrus and peels down the hill to help deter skunks, we have no fence between us. About 4 years ago, we added a staircase and sprinklers and slowly started planting some things.

    It is four trunks about 12 inches apart in almost a line, of poor tasting citrus, they look like lemons but with a loose peel, completely sour with no flavor or sweetness. Not good for eating or cooking.

    They were never more than 5-6 feet tall and looked like a bush from the first time I recall, but once we added sprinklers, trimmed some bottom leaves, they took off. No feeding, just grew to about 15 feet tall. Produced a ton of fruit. Most of the fruit seemed to come from the outer two trunks, but the inside trunks didn’t appear unhealthy, just no fruit. The spot gets great sun and I wanted to remove all four, and put two lemon varieties on the same rootstock where the outer two trees were, so spaced maybe 24” apart. We don’t want an enormous tree anyways, and don’t mind if the experiment goes bad. We have the two trees in plastic pots now and if we plant one, no where else to put the other.

    Just wanted to share our experience with the ‘wild’ citrus we currently have. It is the most vigorously growing citrus we have in our yard. I’m by no means a very experienced gardener.

    1. I think your plan to remove the 4 trees and replace with 2 is a good one. You’ll get rid of trees that aren’t producing fruit you like, and the 24″ spacing should be sufficient IF you keep your trees pruned so the crowns don’t mesh. If you aren’t familiar with natural target pruning please read other posts in this blog so that you understand how to make good pruning cuts.(Also please read our many posts about how to correctly prepare roots in containers before planting.)
      As you noted, water is important, and wood chip mulch is the other necessity. You’ll have healthy, productive trees if you take the proper steps.

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