Asian Pear Root Stock Trial
In 1999 I set about to put in a trial of Asian pears on 2 different Old Home root stocks. I wanted to grow a lot of Asian pears anyway as they do exceedingly well in this area and are almost disease free compared to apples. I purchased rootstock of OHxF 333 and OHxF 69 as semi vigorous or semi dwarf depending on how you look at it. The expected results should be in line with differences in fruit size, tree size, fruit quantity, etc.I chose Old Home because, well mostly because everyone said not to. All the literature, experts, say that you cant use Old Home with Asian pears and for really no substantial reasons that I could find. betulifolia was the common recommended rootstock for Asian Pears, which doesn’t dwarf at all or if you just had to have Old Home then OhxF 97 which generally only dwarfs less than 10%. All the literature, at the time warns against anything but the most vigorous of Old Home root stock.
The biggest concern was fruit size. I already had some experience managing Asian pears on a few different root stocks as during the same period I was working at the WSU Research Station Mt Vernon, WA.My personal experience with these trees was showing me that the dwarfed trees just needed a different type of management. They tend to set huge amounts of fruit which have to be thinned to get adequate size. This seems to be a new concept as far as what has been traditionally been done with Asian pears.So its very possible that reccomendations for root stocks, at the time, were based on the old world, conventional wisdom of the time which was still mostly influenced by commercial growing practices in Asia.
Regardless of the status quo, I needed some more dwarfing effects on my pears or they would not fit into my management system. As long as fruit size is maintained then I can work with smaller trees. Im hoping for a tree around 50-60% of standard.
Tree management system is a 6 wire 7’ high trellis. Trees are 10’ apart, Rows are 10’ apart.
One of my favorite varieties is Kosui but it has a narrow, upright, vigorous growth habit that is hard to tame. Dwarfing rootstocks do help. Olympic, although not quite as bad is also a hard one to control. Others like the Mishirasu and Shinseiki are more natural spreaders and easy to keep within the 7’ trellis.
When grafting these trees I made a minimum of 16 trees each of:
ShinseikiOlympicKosuiIchiban NashiHameseMishirasuUC 1763
These trees were split evenly amongst OHxF 333 and OHxF 69 root stocks. A few years later I also added trees to replace removed ones and these were on OHxF 513 and a few on OHxF 97.
Later in 2002 I added 5 Yoinashi to the block.
The Ichiban Nashi did not do well here. I think its too hot here. It rapidly gets overripe. Soft, winey flavored. I topworked most of them over to Olympic and Kosui.
A few years into the project I noticed what turned out to be Cedar Apple Rust asiaticum on all the Hamese trees. This was devastating to the crop and left the trees in an unhealthy state. This disease came and went with certain weather patterns but was having more on than off years.Since this was part of an organic fruit block using organic sprays was not having any effect and I seriously doubt if spraying anything would have been a sustainable option anyway what with the unpredictable infection periods. I decided to remove all the Hamese. A few years later I noticed the same infections starting up in the Yoinashi. Since by now the Yoinashi had already outgrown their space ( ohxf97 rootstock ) I decided to remove them too.
Results
Size of fruit is always the biggest concern when talking of using dwarf root stalk on Asian pears. Personally I think its mostly just hipe. Lack of real experience behind the talking and the continued passing along of flawed information.Had I done a proper scientific trial with a full size control variety and had I properly thinned, then good comparative results could be had but since we rarely thin anyway… However from a layman's perspective, we get really good size fruit out of this orchard! The Mishirasu, for instance, are so large as to stun our customers. Every year we have several in the 2 – 3 lb category. So far the heaviest one harvested was just over 3 lbs. I chose OhxF333 and OhxF69 because I thought there might be some growth differences between them. As it turns out, at least in my growing conditions, they both have produced fairly similar trees. Trunk diameters are about the same. Numbers of blossoms and fruit are about the same. Size of fruit is about the same.
Conclusions
This was by no means a scientific trial. First of all I didn’t include a control in my trial. It being my trial and only having to answer to myself with the results I felt comfortable without a control. The control would have been the same varieties repeated on something like betulifolia which at the time of conception of this trial, was the most recommended root stock for Asian Pears. I felt certain enough what those results were going to be, not only after my years of experience with managing Asian Pear trees at the Research Station but also with the few Asian Pear trees I had planted on the farm prior to developing this trial plot. I was talked into purchasing my first Asian Pear trees on betulifolia by a well known nursery in Oregon. That was a disaster.Most of all and this is something I cant stress enough, dwarf trees on a trellis are grower friendly so getting a dwarfed Asian pear is most important so that proper management can be implemented. The sizing of fruit on the varieties that tend to overbear will be much easier to secure with proper thinning, something that cant be accomplished with a standard tree.Another thing to consider is just how brittle most Asian pear branches are. The common practice, with apples and even European pears, of letting fruit load naturally bend the branches to keep tree stature lower will very likely result in broken trees. This is all solved with a trellis, of course.
Looking forwardSo, some 25 years later the experiment is no longer an experiment but is in full use for commercial production. The Asian pear block is in major need of tree removal, at this point, to alleviate overcrowding. The original in row spacing of 10’ is not enough for the mature trees of most of these varieties. Logic dictates the removal of every other tree. Even if the remaining trees don’t ever completely fill in the spaces the remaining trees will benefit greatly from the increased air passage and light penetration.
No new varieties have been planted for some time but space remains and plans are underway for adding Shin Li and Dasui Li to the line up.
Asian Pear Root Stock Trial
In 1999 I set about to put in a trial of Asian pears on 2 different Old Home root stocks. I wanted to grow a lot of Asian pears anyway as they do exceedingly well in this area and are almost disease free compared to apples. I purchased rootstock of OHxF 333 and OHxF 69 as semi vigorous or semi dwarf depending on how you look at it. The expected results should be in line with differences in fruit size, tree size, fruit quantity, etc.
I chose Old Home because, well mostly because everyone said not to. All the literature, experts, say that you cant use Old Home with Asian pears and for really no substantial reasons that I could find. betulifolia was the common recommended rootstock for Asian Pears, which doesn’t dwarf at all or if you just had to have Old Home then OhxF 97 which generally only dwarfs less than 10%. All the literature, at the time warns against anything but the most vigorous of Old Home root stock.
The biggest concern was fruit size. I already had some experience managing Asian pears on a few different root stocks as during the same period I was working at the WSU Research Station Mt Vernon, WA.
My personal experience with these trees was showing me that the dwarfed trees just needed a different type of management. They tend to set huge amounts of fruit which have to be thinned to get adequate size. This seems to be a new concept as far as what has been traditionally been done with Asian pears.
So its very possible that reccomendations for root stocks, at the time, were based on the old world, conventional wisdom of the time which was still mostly influenced by commercial growing practices in Asia.
Regardless of the status quo, I needed some more dwarfing effects on my pears or they would not fit into my management system. As long as fruit size is maintained then I can work with smaller trees. Im hoping for a tree around 50-60% of standard.
Tree management system is a 6 wire 7’ high trellis. Trees are 10’ apart, Rows are 10’ apart.
One of my favorite varieties is Kosui but it has a narrow, upright, vigorous growth habit that is hard to tame. Dwarfing rootstocks do help. Olympic, although not quite as bad is also a hard one to control. Others like the Mishirasu and Shinseiki are more natural spreaders and easy to keep within the 7’ trellis.
When grafting these trees I made a minimum of 16 trees each of:
Shinseiki
Olympic
Kosui
Ichiban Nashi
Hamese
Mishirasu
UC 1763
These trees were split evenly amongst OHxF 333 and OHxF 69 root stocks. A few years later I also added trees to replace removed ones and these were on OHxF 513 and a few on OHxF 97.
Later in 2002 I added 5 Yoinashi to the block.
The Ichiban Nashi did not do well here. I think its too hot here. It rapidly gets overripe. Soft, winey flavored. I topworked most of them over to Olympic and Kosui.
A few years into the project I noticed what turned out to be Cedar Apple Rust asiaticum on all the Hamese trees. This was devastating to the crop and left the trees in an unhealthy state. This disease came and went with certain weather patterns but was having more on than off years.
Since this was part of an organic fruit block using organic sprays was not having any effect and I seriously doubt if spraying anything would have been a sustainable option anyway what with the unpredictable infection periods. I decided to remove all the Hamese. A few years later I noticed the same infections starting up in the Yoinashi. Since by now the Yoinashi had already outgrown their space ( ohxf97 rootstock ) I decided to remove them too.
Results
Size of fruit is always the biggest concern when talking of using dwarf root stalk on Asian pears. Personally I think its mostly just hipe. Lack of real experience behind the talking and the continued passing along of flawed information.
Had I done a proper scientific trial with a full size control variety and had I properly thinned, then good comparative results could be had but since we rarely thin anyway… However from a layman's perspective, we get really good size fruit out of this orchard! The Mishirasu, for instance, are so large as to stun our customers. Every year we have several in the 2 – 3 lb category. So far the heaviest one harvested was just over 3 lbs. I chose OhxF333 and OhxF69 because I thought there might be some growth differences between them. As it turns out, at least in my growing conditions, they both have produced fairly similar trees. Trunk diameters are about the same. Numbers of blossoms and fruit are about the same. Size of fruit is about the same.
Conclusions
This was by no means a scientific trial. First of all I didn’t include a control in my trial. It being my trial and only having to answer to myself with the results I felt comfortable without a control. The control would have been the same varieties repeated on something like betulifolia which at the time of conception of this trial, was the most recommended root stock for Asian Pears. I felt certain enough what those results were going to be, not only after my years of experience with managing Asian Pear trees at the Research Station but also with the few Asian Pear trees I had planted on the farm prior to developing this trial plot. I was talked into purchasing my first Asian Pear trees on betulifolia by a well known nursery in Oregon. That was a disaster.
Most of all and this is something I cant stress enough, dwarf trees on a trellis are grower friendly so getting a dwarfed Asian pear is most important so that proper management can be implemented. The sizing of fruit on the varieties that tend to overbear will be much easier to secure with proper thinning, something that cant be accomplished with a standard tree.
Another thing to consider is just how brittle most Asian pear branches are. The common practice, with apples and even European pears, of letting fruit load naturally bend the branches to keep tree stature lower will very likely result in broken trees. This is all solved with a trellis, of course.
Looking forward
So, some 25 years later the experiment is no longer an experiment but is in full use for commercial production.
The Asian pear block is in major need of tree removal, at this point, to alleviate overcrowding. The original in row spacing of 10’ is not enough for the mature trees of most of these varieties. Logic dictates the removal of every other tree. Even if the remaining trees don’t ever completely fill in the spaces the remaining trees will benefit greatly from the increased air passage and light penetration.
No new varieties have been planted for some time but space remains and plans are underway for adding Shin Li and Dasui Li to the line up.
2 of 3 rows, 9 years into the project.
2 of 3 rows, 9 years into the project.
Olympic
Olympic
Mishirasu
Mishirasu
Shinseiki
Shinseiki
My kids, quite a few years ago, gorging themselves on their favorite, the Kosui.
My kids, quite a few years ago, gorging themselves on their favorite, the Kosui.