yoderjac
5 year old buck +
I was asked this question on the AU Buck thread but since it applies to rootmaker grown trees in general, I decided to start a new thread:
Planting Rootmaker Trees in Heavy Clay Soil
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yoderjac
5 year old buck +
Background:
Root pruning containers work by air pruning, trapping, or constricting roots which causes upstream branching. The result is a very dense efficient root system. This works best when you use a chunky professional mix like Promix, or Fafard 3B, 56, or other similar mix. In fact in the larger Rootbuilder II containers, I mix mini pine bark nuggets 50/50 with Promix. There are several reasons for this first, the combination of the container and mix makes them very well drained. It is practically impossible to give them too much water as excess simply drains out, but you can water them too often. Because you are developing a very dense root system, the roots need some place to grow. The voids in the chunky mix provide a place for the roots to grow when they branch upstream. In fact, one of the ways to determine it is time to transplant them to a larger container is when they become difficult to top water. When the roots fill the voids, the containers are much less well drained. It takes much longer for water to penetrate. It takes a long time to water them thoroughly.
Unlike bare root trees that need to be planted dormant, the rootbuilder II containers unwrap and the root ball can be planted without any disturbance. Since the roots are air pruned as they grow and hit the protrusions on the sides of the container and are directed to the holes at the end, there is no circling or j-hooking. So, you don't have to remove medium and hand prune circling roots like you do with threes grown in smooth containers. This means trees can be planted any time of the year if supplemental water is provided when needed and trees begin growing immediately rather than a year of sleep, and a year of creep, before they finally leap.
The issue with planting in heavy clay:
There is a large difference in water infiltration between heavy clay and the chunky medium used in this container system. When you plant trees in heavy clay, you normally don't amend the soil because amended soil infiltrates water much faster. You essentially form a pond with amended soil and can drown the tree. So, when planting bare root trees, I use the native clay. If I did this with rootmaker trees, I'd lose the advantage of not disturbing the root ball. The second problem with amended soil in heavy clay is the reverse. Again because water infiltrates faster both on the way in (rain) and out (evaporation). It does not retain water as well as clay, so during dry periods, the tree can die without supplemental water.
Wildlife trees are a special situation:
For the back yard orchardist, supplemental water can generally be provided when needed. This may be true for folks who live on their hunting land and are only planting a few trees for attraction. However, when planting trees in volume for wildlife, low maintenance becomes important. It is difficult at best, and in many cases impossible, to provides supplemental water.
Disclaimer:
I'm not suggesting this is the best way to plant trees in all cases. In my area, we get fairly dependable spring and fall rain. Summers usually have sporadic rain but we can have long dry periods during summer. I'm in zone 7A for reference.
Techniques:
The starting point is site selection. In addition to the normal site selection criteria, you want to pic a local spot where ground water from the surrounding 10+ feet will not drain.
It may be hard to tell from this picture, but the auger is over a slightly higher area. Just to the right of the rear tire is an area where water will drain. That is where you don't want to plant.
After I auger the hole, there may or may not be glazing on the sides depending on soils conditions when I dig. If I do get glazing, I simply use a hand rake to rough up the sides of the hole. There are two important factors to the hole, depth and diameter. For my area 2 1/2 feet to 3 feet works well.
Once the hole is dug and the sides hand raked if necessary, I use a hand-held post hole digger to clean the bottom of the hole. . I then amend the soil in the bottom of the hole. You can use normal soil amendments (peat, bark, manure, etc.) but the objective is for good drainage. I typically use quarry stone mixed with a little native clay because it infiltrates well and does not settle. I fill the hole with the amendments far enough so that when I insert the root ball, the top of the medium is about an inch above ground level.
This picture shows how the RB 2 container unwraps from the root ball.
The next picture shows the root-ball sitting in the hole. Note how close the hole diameter is to the root-ball and that the top of the root-ball is about an inch above the soil line.
Finally I use the native clay to build a mound and cover the root-ball. This keeps any ground water from draining into the hole. The only water that gets into the hole is rain that falls on it.
After this, you can take any normal steps like landscaping material for weed control, tubes or cages for protection.
How this works:
When we get heavy spring rain, it infiltrates the promix but collects below the root-ball thus not drowning the tree. Trees grow roots smartly. They grow near ponds and streams all the time. I'm not at all worried about the roots as they grow. This covers spring. Because the diameter of the hole is very close to the diameter of the root-ball, the lateral roots will quickly grow into the native clay. By summer when our dry periods come, the roots will have access to the clay which holds water well. Planting from 3 gal RB2 containers works the best using an 9" auger bit, the same thing will work for a 1 gal RB2 using a 6" auger bit. The depth of the hole depends on how much rain you get in the spring. The idea is to make it deep enough to keep the root ball from being inundated
This works well in my soil with my climate. Adapt as needed for yours.
Thanks,
Jack
Root pruning containers work by air pruning, trapping, or constricting roots which causes upstream branching. The result is a very dense efficient root system. This works best when you use a chunky professional mix like Promix, or Fafard 3B, 56, or other similar mix. In fact in the larger Rootbuilder II containers, I mix mini pine bark nuggets 50/50 with Promix. There are several reasons for this first, the combination of the container and mix makes them very well drained. It is practically impossible to give them too much water as excess simply drains out, but you can water them too often. Because you are developing a very dense root system, the roots need some place to grow. The voids in the chunky mix provide a place for the roots to grow when they branch upstream. In fact, one of the ways to determine it is time to transplant them to a larger container is when they become difficult to top water. When the roots fill the voids, the containers are much less well drained. It takes much longer for water to penetrate. It takes a long time to water them thoroughly.
Unlike bare root trees that need to be planted dormant, the rootbuilder II containers unwrap and the root ball can be planted without any disturbance. Since the roots are air pruned as they grow and hit the protrusions on the sides of the container and are directed to the holes at the end, there is no circling or j-hooking. So, you don't have to remove medium and hand prune circling roots like you do with threes grown in smooth containers. This means trees can be planted any time of the year if supplemental water is provided when needed and trees begin growing immediately rather than a year of sleep, and a year of creep, before they finally leap.
The issue with planting in heavy clay:
There is a large difference in water infiltration between heavy clay and the chunky medium used in this container system. When you plant trees in heavy clay, you normally don't amend the soil because amended soil infiltrates water much faster. You essentially form a pond with amended soil and can drown the tree. So, when planting bare root trees, I use the native clay. If I did this with rootmaker trees, I'd lose the advantage of not disturbing the root ball. The second problem with amended soil in heavy clay is the reverse. Again because water infiltrates faster both on the way in (rain) and out (evaporation). It does not retain water as well as clay, so during dry periods, the tree can die without supplemental water.
Wildlife trees are a special situation:
For the back yard orchardist, supplemental water can generally be provided when needed. This may be true for folks who live on their hunting land and are only planting a few trees for attraction. However, when planting trees in volume for wildlife, low maintenance becomes important. It is difficult at best, and in many cases impossible, to provides supplemental water.
Disclaimer:
I'm not suggesting this is the best way to plant trees in all cases. In my area, we get fairly dependable spring and fall rain. Summers usually have sporadic rain but we can have long dry periods during summer. I'm in zone 7A for reference.
Techniques:
The starting point is site selection. In addition to the normal site selection criteria, you want to pic a local spot where ground water from the surrounding 10+ feet will not drain.
It may be hard to tell from this picture, but the auger is over a slightly higher area. Just to the right of the rear tire is an area where water will drain. That is where you don't want to plant.
After I auger the hole, there may or may not be glazing on the sides depending on soils conditions when I dig. If I do get glazing, I simply use a hand rake to rough up the sides of the hole. There are two important factors to the hole, depth and diameter. For my area 2 1/2 feet to 3 feet works well.
Once the hole is dug and the sides hand raked if necessary, I use a hand-held post hole digger to clean the bottom of the hole. . I then amend the soil in the bottom of the hole. You can use normal soil amendments (peat, bark, manure, etc.) but the objective is for good drainage. I typically use quarry stone mixed with a little native clay because it infiltrates well and does not settle. I fill the hole with the amendments far enough so that when I insert the root ball, the top of the medium is about an inch above ground level.
This picture shows how the RB 2 container unwraps from the root ball.
The next picture shows the root-ball sitting in the hole. Note how close the hole diameter is to the root-ball and that the top of the root-ball is about an inch above the soil line.
Finally I use the native clay to build a mound and cover the root-ball. This keeps any ground water from draining into the hole. The only water that gets into the hole is rain that falls on it.
After this, you can take any normal steps like landscaping material for weed control, tubes or cages for protection.
How this works:
When we get heavy spring rain, it infiltrates the promix but collects below the root-ball thus not drowning the tree. Trees grow roots smartly. They grow near ponds and streams all the time. I'm not at all worried about the roots as they grow. This covers spring. Because the diameter of the hole is very close to the diameter of the root-ball, the lateral roots will quickly grow into the native clay. By summer when our dry periods come, the roots will have access to the clay which holds water well. Planting from 3 gal RB2 containers works the best using an 9" auger bit, the same thing will work for a 1 gal RB2 using a 6" auger bit. The depth of the hole depends on how much rain you get in the spring. The idea is to make it deep enough to keep the root ball from being inundated
This works well in my soil with my climate. Adapt as needed for yours.
Thanks,
Jack
Last edited:
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