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There are so few things in my life I'm sure of like- whether or not my car will start when I turn the key or whether or not my internet connection will actually connect during rainy weather. June2011 010.jpgHowever, there is one thing that I know- plastic lunch bags stapled around a developing fruit will give me perfect fruit!!

This is my fourth year of bagging and each time I have had perfect apples. See the adjacent picture as proof for what I'm talking about! IMG_3544.JPG

For protecting my apples I prefer to use the most basic of basic plastic bags stapled to itself. Other friends of mine prefer to use ziploc bags that don't need to be stapled. Either way, it will work with whatever bag you use as long as it's put on the apples before apple maggot flight time, which is around July 4th around the Twin Cities in Minnesota. (For more information on apple maggot in MN click here).

There are a lot of skeptics to this approach since it does seem like a lot of work. However, it really isn't! Depending on amount of apples per tree, the size of the tree, how much thinning needs to be can expect to bag approximately 1 to 2 apples per minute. Of course, like anything the speed at which you work will only improve with time!

Is this really more time consuming than doing a chemical spray which includes up to 6 sprays over the summer if you want complete protection? No, at least not in my opinion! Now in all fairness I've never done a chemical spray regime so don't really know the exact length of time that's needed. I would love to hear from anyone how much time they spend doing the chemical sprays so we can compare. Please comment to get this conversation going!

To read more from the person who invented this concept click here

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Winter 2011 in Minnesota, one of the snowiest we've had to deal with in history, was definitely one that brought way more snow that I thought we'd have to deal with at the nursery!

It's now the beginning of April, the snow has begun to melt and the damage incurred over the winter can now be seen along the stem or branches where rabbits were nibbling. With all the snow, this year rabbits and other vermin were able to reach to a new height of plant tissue which they then devoured.

Never in a million years did I expect to have the extent of the rabbit damage that we have. All of my eight Honeycrisp apples that I'm training to grow on our espalier now look like corn on the cob remnants. Or should I say, "was training" because obviously they were killed by the near complete removal of bark from a majority of the plant by rabbits or other pests. And really, "corn on the cob" is best stated as "apple on the cob."

The good news is that most of the other plants in the display area of the nursery were protected with fencing and/or tree tubes so will spring to life in a few weeks as the temperatures and daylight hours continue to increase.

Any shoulda/woulda/couldas? Yes, yes and another yes! Had I known we were going to be getting ten feet of snow- ok, maybe only two or so- I would have wrapped all these apple trees to protect them from the ravages of rabbit teeth! I would have wrapped every square inch of these delicate little trees that I've been so diligently training for the past 2 growing seasons so they wouldn't all be lost in one season by a chunky little rabbit.

For information on critter (aka. vermin) damage click here

What will happen with these 8 Honeycrisp apple trees? Depending on the extent of the damage- assuming only the scion was damaged- I will begin retraining a new stem and branches for our espalier.

As more snow melts with the rising temperatures, I will get a chance to peruse the rest of my fruit tree plantings and see what other damages this hellish winter brought to them. Stay tuned!

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In May, 2010 I decided to take on the responsibility of filling an open pit out at the Nursery with a soil concoction suitable for growing blueberries, cranberries and lingonberries. Perfect- plants I need to learn how to grow for Twin Cities yards! These berries or Vacciniums require an unique soil to most areas of the Twin Cities- a soil pH under 5.5, so I needed to order and have shipped in special concoction.

vaciniumbox.jpgThe final combination I selected was 50% coarse sphagnum peat, 25% sand and 25% topsoil. Peat was chosen because of it's low pH but the expense left the volume to be only 50% of the total. Sand was selected to increase drainage and top soil was chosen for nutrition, aeration and to reduce the peat muckiness.

The soil was mixed and the bed was filled by Landcare at the U on May 18th and plants were put in on June 7th by me and one of the team members.

IMG_3368.JPGNow before I go any farther in this write-up I'm going to admit that there are several things I did out of order and against the recommendations of very wise blueberry growers and even UMN scientists. My explanation, which may or may not be believable, is the need to make quick decisions based on time and cost of materials = the typical excuses!

So I did things out of order and am now needing to correct the mistakes I made and will be doing so for the next years. I knew this would happen, but one can never fully prepare for these corrections.

The error I'm going to talk about here is with the soil and the pH of the soil concoction, which I THOUGHT was going to be much closer to the low pH we needed. Staring off, the soil analysis for the coarse sphagnum peat is 3.7, sand 7.8 and field soil at 7.3 so I figured the resulting combination would be no more than pH 6.5. What a silly assumption for me to have!

After a couple months, I finally took the time to bring a soil sample into the Soil Testing Laboratory and was a little shocked by the first reading we got back- pH 7.1!!! So much for the hundreds of dollars invested in the peat! Ok, ok...maybe there are other benefits to having peat in blueberry plantings but still, our pH is only a little better than had we just used the field soil! Because of the slight chance an error was made at the laboratory, another soil test will be taken and submitted this year.

But now, it's time for corrections. On the soils test a sulfur recommendation came back that read 5.8 lb per 100 sq. ft in order to bring the pH down. So, the team and I figured out how much that meant for our bed that is 374 sq. ft, which comes to 22 lbs (0.058 lbs per foot x 374 sq ft= ~22 lbs). On August 4th we mixed 22 lbs of elemental sulfur to the top 2-6 inches of the soil using a little garden rake for around the plants and a mini-rototiller in between the plants. Next spring me or a team member will take another soil sample to see if the sulfur has had any affect on lowering the pH.

Soil pH is probably the biggest challenge we'll be having to face with our Vaccinium planting. Of course, that story may change after we see how the plants live with the rabbits and chipmunks during the winter months!

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IMG_3348.JPG The other day down at the nursery, around July 21st, 2010 yellowing leaves on two Summercrisp pear trees were observed. Within three days, the leaves on one of the trees were completely brown but still attached and by this time, the leaves of a third tree were yellowing.

What is going on with these trees?

To give a little background, these pear trees were purchased from Bailey Nurseries, are Summercrisp scion on a semi-dwarf rootstock (Old Home S333) and were planted bare-root in the spring of 2008. However, it wasn't until 2010 that foliar problems were first observed. One thing that had happened in 2010 that didn't happen in 2008 or 2009 was a swing of temperatures down below freezing while the leaves of the trees were expanding and an incredibly wet early summer through mid-summer with intermittent extremes of heat. With these climatic extremes could any of them be causing problems later in the growing season of 2010? What other observations have been made?

Other observations that have been made include the scratch test on branches and stem. When done on the lower branches, the scratch test reveals a green cambium. Well, if green it must be alive so what's the problem?! Well, the scratch test done around the circumference of the stem shows something different- a brown cambium. Brown cambiums = dead as door nails.


Now not all areas of the cambium on the stem are brown, only a specific region is showing a brown cambium but it is also this area that's awfully precarious for other reasons. If you look at the adjoining image, you see a compressed area of the stem flanked by swollen areas above and below the compression. Pear_stem-taper_Canker-lores_0552D.Hanson.jpgIt's obvious- this compressed area of the stem is dead thereby restricting the movement of water from the roots to the leaves and photosynthates from the leaves to the roots. But how or why is this compression happening...and on only a few of the trees?

At this moment, the answer is unclear. With the help of Dimitre Mollov from UMN Plant Disease Clinic, Chad Giblin, Dave Hanson and Gary Johnson a few potential problems have been given as options. First off, for critter damage all of these trees were protected by white stem guards during the winter months, which happened to be left on into May. Were these guards on so long that the moisture buildup was too intense under the guards to damage the cambium? The cold snap the Twin Cities experienced in April was after early growth was seen on the pears. Active growth was occurring on the trees so were out of winter dormancy, did this cold snap kill the cambium of the stem in areas already weakened by possibly the stem guard?

But another thought has been raised that looks back at 2009 as the time problems arose on the trees. The noticeable swelling of the stems points to more than just a few months of growth in 2010- all this growth would possibly have to include the growing season of 2009. Could possibly a pathogen (canker?) of some sort girdle the stem in 2009 and the tree, with enough stored energy, leaf out this year and then fail in 2010?

It has been observed by two great pathologists, Dimitre Mollov and Dr. Blanchette that this cambial death looks mostly like winter damage caused by the extreme lows. It doesn't completely make sense why these particular trees were affected in this particular area of the stem, but of anything, it's the best observations I have. It would make more sense if Bailey's had used a non-cold tolerant interstem in their grafting but that doesn't look to be the case.

Lesson learned? Maybe even U of MN releases aren't 100% cold hardy?

Be well,

Photos: Top- Rebecca Koetter, Middle- Dave Hanson, Bottom- Dave Hanson

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Thumbnail image for rkoetter.thumbnail.jpg
2009septemberapples 004.jpgRebecca Koetter manages a myriad of demonstration plots at the Urban Forestry & Horticulture Research Institute covering many different methods of fruit production for the home gardener.

She is currently exploring espalier and other training methods for no-spray apple and pear production. 

In 2010, Rebecca will be adding blueberry, cranberry, lingonberry demonstration plots at The Institute's research nursery.

Join Rebecca at the 48th annual Minnesota Shade Tree Short Course at Bethel University in Arden Hills, MN!
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