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The Urban Forestry & Horticulture Research Nursery was born from the 25 year legacy of the TRĒ Nursery program, located on the University of Minnesota’s Agricultural Experiment station on the St. Paul Campus. In 2009 we closed the doors on the TRĒ Nursery and have expanded our focus to serve a wider constituency including professional arborists, garden center employees, nursery growers, private citizens, and urban foresters.

Research and outreach here is focused on the work of Professors Gary R. Johnson and Jeffrey H. Gillman. The heart of the project is our 10 acre research nursery located right in the middle of St. Paul, MN. Here we work a wide range of research projects, teach University undergraduates, and offer outreach education to the industry.

This site is very interactive! Feel free to comment here - make your voice heard! Join us in the effort to create landscapes with healthy, vibrant plants for the benefit of everyone!

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On Saturday June 8th, around 30 volunteers helped plant baby oak seedlings that will hopefully take the place of their parents as they slowing start to decline from age.
Designated as a park in 1908, Newell Park is one of the oldest parks in St. Paul. One of the most notable features that separates it from other parks in St. Paul are the pre-settlement mature Bur Oaks that create a dense canopy over the entire park. Unlike in a natural system, regeneration of new oak trees from fallen seeds does not occur due to the heavy use as an urban park. In efforts to regenerate oak trees in Newell Park, we teamed up with the City of St. Paul Forestry to plant baby oak seedlings germinated in our greenhouse from Bur Oak acorns collected in the park. For now, only a small wooded area located in the northeast corner of the park was planted with baby seedlings (shown bellow). In addition to the oak seedlings, bare root Carpinus and two different varieties of Amelanchier (Serviceberry), both native understory species, were planted on the reNewell site to further restore the park.
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The first oak tree being planted!
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The image bellow shows the site after all the oaks were planted. Inside each of the white tubes seen in the image are baby oak seedlings. Tree tubes are commonly placed on seedling trees to protect them from the getting eaten by animals or stepped on by humans. Additionally, the tube acts as a mini greenhouse that encourages the seedling to grow faster and straighter. The tube is removed shortly after the tree grows out the top of the tube.
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Instead of using a truck to transport the bare root Carpinus and Amelanchier and flat of oaks, we carried the trees down to Newell Park from the nursery using our bicycle trailers!! Bellow is a team shot taken before we started our ride to Newell Park

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This year we're teaming up again with Saint Paul Parks & Recreation to add a few more flowering cherry trees at the Mannheimer Memorial in historic Como Park.

Last year, we had the great honor of taking care of the Spring Wonder flowering cherries (Prunus sargentii 'Hokkaido Normandal') prior to the planting that celebrated the 100th Anniversary of the original donation to the United States from Japan in 1912.   

I finally got our stereoscope linked up with our digital camera and thought to share some VERY close up photos from our flowering cherry collection.  Photos like this really help me appreciate the wonder of spring and how great and beautiful things are possible from such simple beginnings!

Kwanzan (Prunus serrulata 'Kwanzan')

Kwanzan Buds

Yoshino (Prunus x yedoensis)
Yoshino flowering cherry buds

Pink Flair (Prunus sargentii 'JFS-KW58')
Pink Flair Flowering Cherry Buds'

Both Kwanzan and Yoshino flower cherry trees have long-standing popularity throughout the warmer regions of the USA.  With warmer winters and success with other species released for USDA Hardiness Zone 5, these are definitely worth a try in the Twin Cities.  We can't wait to see if these trees will put on a beautiful display of double pink blossoms!

Pink Flair arrived in Minnesota via a donation from J. Frank Schmit & Son nursery in Boring, OR.  It is a P. sargentii just like the Spring Wonder trees planted last year, and both have exquisite single pink blossoms.

Stay tuned for updates on the flowering cherry plantings at Mannheimer and for news on the activities planned for 2013.
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Check out this neat time-lapse video of our elm grafting process! Created by our very own J.W. Fillmore...and featuring American elm roostocks from our friends at Three Rivers Parks District Nursery.

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ArmAld Blvd Conditions (2).JPGHave you heard of Prairie Horizon Manchurian alder?  Not many have, but Minneapolis Park & Recreation Board got a big dose last fall during the installation of a new research project in the Armatage neighborhood in southwest Minneapolis.

Prairie Horizon cut its teeth on the tough and dry plains at NDSU's woody plant breeding program led by Dr. Dale Hermann (ret.)  We've had some great previous success in Armatage with Prairie Horizon, so we decided it was time for a little expansion.

We took Prairie Horizon grown in both the gravel bed and RootTrapper fabric containers and planted them in typical Minneapolis boulevard conditions with different combinations of SylvaSoil (an organic compost product) as an amendment.

Armatage is known for its high concentration of ash, so being prepared for potential losses due to EAB is really important.  With results from this research we hope to find more trees that will fill open planting sites and create soil conditions that will enhance their long-term survival and establishment.

See above and below for a photo-essay of my days entrenched with the arborists of MPRB!

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While it will be several 2 to 3 years before we'll have realistic results, check back often as we'll post news about the trees in Armatage and check in on their ongoing performance. 


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Last fall I had the opportunity to join Mr. Don Willeke in observing the removal of a large 'Iowa State' American elm at his neighbor's house in the Dean Park area of Minneapolis. This large tree was planted in 1978, shortly after Don grafted it onto a wild American elm seedling.  Unfortunately, the tree had developed major defects over the years (it had already been cabled and braced) and required removal for safety purposes. 

Don is a local elm aficionado and has been "speaking for the trees" since the 1970s. He has been my host on many visits to the forest of elm trees (amongst other species) in and around his Dean Park home.

'Iowa State' was discovered and screened by Prof. Sandy McNabb at Iowa State University from the late 1960s to early 1970s where it proved to be quite resistant to Dutch elm disease (DED) when inoculated with the fungus. While not widely released (at least to my knowledge) this tree remains an important reminder of those lucky escapes - native American elms with high tolerance to DED. Unfortunately, the structure of this tree is less than ideal as it has a tendency to form weak branch unions due to inclusions and very acute angles of attachment.

Like 'Iowa State', many of the trees surrounding Don's home and neighborhood are from the breeding and selection programs of Dr. Eugene Smalley and Ray Guries, Dr. Alden Townsend, and Dr. George Ware. This section of the Minneapolis urban forest is truly a testament to the tireless work of these great scientists and homage to a Golden Age of elm selection and breeding.


In my ongoing efforts to make-lemonade-outta-lemons I worked with Don and Jay Linn from Log and Limbs Company (who was performing the removal) to collect some prime cuttings material for cloning of this now rare tree.  

By the end of the removal process Don and I were able to collect some vigorous vegetative shoots from the very top of the tree, which I brought back to the University for propagation and inclusion into our elm program.

Now, weeks later, I transplanted some of the first rooted cuttings of 'Iowa State' and can now add this tree to the growing collection of elms at the University of Minnesota.

Rooted IA State Cuttings

Plants are also slated for distribution to the USDA National Arboretum in Maryland for inclusion into their continuing work on the American elm.


IA_StateDon and Iowa State "Cookie"
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This December Jonathon and I (Greg) trekked out around Minneapolis collecting cuttings for asexual propagation for the Heritage project and came across this champion black willow (Salix nigra). Willow is considered to be a short lived tree that is prone to decay and failure because it grows too quickly for its own good. That is a good thing if you need a large tree fast but not if you want a tree that will last longer than you. This champion willow is located right across from the main parking lot of Lake Nokomis by field #5 if you care to see it up close. The circumference of the trunk is 379 inches and it stands 70ft. tall with an average canopy spread of 73.5ft! What a monster!
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Jonathon Standing IN the monster!

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Even with decay regularly pruned out this tree is still huge!

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For the tree of the week, I chose the Minneapolis Heritage Horse Chestnut (Aesculus hippocastanum). This is the largest Horse Chestnut in the city, and it is right in front of Folwell hall on East Bank Campus! I would walk right by this tree every day, and until recently never took the time to notice it. It used to have another similar Horse Chestnut across the sidewalk, but that has been replaced with a new tree.


Horse Chestnuts are native to Greece and Albania, but are now widely cultivated in parks and urban areas. They grow very slowly, but can reach 50' to 75' on average, with some up to 100'. They grow taller than they are wide, and have a dome shaped or oval final form. The name comes from their large, hard seeds, that were once believed to cure horse chest ailments, but have since been proven to be poisonous. The seeds, which can be messy, and dangerous if ingested, along with their tendency to grow to massive size are the main concern when planting a horse chestnut.

Despite this, they enjoy enormous popularity.They are hardy trees, in zone 3, making them great candidates for Minneapolis. They also do well in most soil types, preferring moist roomy soil. The trees have showy white, yellow, and red flowers and rich foliage.

Other than this heritage sample, the Horse Chestnut has enjoyed popularity as a common choice for German beer gardens. It was a common choice because of its wide deep shade, that kept patrons cool. Also, the "Anne Frank Tree", which Anne Frank mentions in her diary multiple times, was a Horse Chestnut. It was locate in the middle of Amsterdam. This tree sadly blew over in 2010, weighting in at 27 metric tons.

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Many of my friends assume that I am out of the job now that the snow has fallen, and the 


days are short and cold. Although we don't get outside as much anymore, there is still a lot of work for team tree over the winter months. Recently, we drove out to St. Paul to take data on the High Bridge dog park. There is an earlier article that talks about the dog park in more detail, but it is basically a remidation site where we planted groups of 1 1/2" caliper trees on the site of a former rail yard for a coal plant. The site is a difficult place for trees, with poor soil conditions, and of course, lots of dogs, who may or may not be nice to the trees we planted. We have been taking data for awhile on how well they are growing to see what varieties do well in the adverse conditions.

During our check up on the trees, we were going to collect data on caliper and take photos of 


the trees. 

Sadly, many of the trees have lost all their cambium at some points, which will most likely kill the trees. Chad said that when he originally checked the site out, the trees in the surrounding area showed signs of damage from critters, and there was probably a lot of them living in the area.

The remaining trees that survive the winter will make it to the 2" caliper mark, where the bark usually will become hard and inedible. Also, there was generally less damage on Catalpa, Birch, and Alder than other varieties. 

Team Tree met up with some Saint Paul Forestry after our initial visit and wrapped the stems, so some of the trees will make it to spring!

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We say goodbye to another member of Team Tree. Greg was the most senior member of team


 tree, and was a very valuable addition. He was the only one who could give Chad a run for his money on Skiddy, has extensive horticultural knowledge, and lots of nursery experience. Greg graduated with a degree in horticulture and is working at a landcare company in the southwest metro area.

Greg, you will be missed. The best of luck in your future endevors

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