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Showing posts from November, 2014

Pine Wilt

USDA Forest Service
Photo 1: Scots pine killed by pine wilt
Dan Miller, MN Landscape Arboretum

Two mature Scots pines (Pinus sylvestris) at the Minnesota Landscape Arboretum started showing tan-colored needles at the end of the summer this year and by late September both trees were dead. When one of the trees was being removed, Assistant Gardener Mike Walters noticed a blue stain in the sapwood of the tree and from his previous experience with a tree care company in southeastern Iowa; he suspected the tree had been killed by nematodes. Cross-sections of the blue-stained wood were soaked in water and nematodes, microscopic roundworms, could be observed with a dissecting microscope. A sample was then sent to the University of Minnesota Plant Disease Clinic and they confirmed the presence of the pine wood nematode (Bursaphelenchus xylophilus). This nematode is the primary cause of pine wilt disease.


Dan Miller, MN Landscape Arboretum
Photo 2: Cross section of a Scots pine infected w…

November 3rd 2014 Issue of Yard and Garden News

The BEST Crabapples for Minnesota: Part III- Table & References

Mary H. Meyer, extension horticulturist and professor, University of Minnesota


Mary Meyer
Table 1: BEST Crabapples for Minnesota
References and Further Reading:

Beckerman, J., J. Chatfield, and E. Draper. 2009. A 33-year Evaluation of Resistance and Pathogenicity in the Apple Scab-crabapples Pathosystem. HortSci. 44(3):599-608.

Chatfield, J. A. E. A. Draper, and B. Cubberley. 2010. Why Plant Evaluations Matter. American Nurseryman 210(9):10-15.

Draper, E. K., J. A. Chatfield, and K. D. Cochran. 2005. Marvelous Malus--Ten Crabapples Worthy to Know, Show, and Grow. Brooklyn Botanic Garden. Accessed October 6, 2014.

Green, T. L. 1995. Results of the national crabapple evaluation program. Accessed online October 3, 2014.

Green, T.L. 1996. Crabapples--When you're choosing one of those apple cousins, make flowers your last consideration. Amer. Horticult. 75:18-23.

Guthery, D.E. and E.R. Hasselkus. 1992. Jewels of the landscape. Amer. Nurseryman 175(1):28-41.
Iles, J. 2009. Crabapples.…

The BEST Crabapples for Minnesota: Height, Fruit, Scab Resistance and Finally: Flowers - Part II

Mary H. Meyer, extension horticulturist and professor, University of Minnesota


Mary Meyer
Photo 1: Adirondack close-up
Mary Meyer Photo 2: Adirondack - whole tree
Mary Meyer Photo 3: Beverly close-up
Mary Meyerd Photo 4: Beverly - Whole tree
Mary Meyer Photo 5: Bob White close-up
Mary Meyer Photo 6: Bob White - whole tree
Mary Meyer Photo 7: Donald Wyman - whole tree
Mary Meyer Photo 8: Firebird close-up
Mary Meyer Photo 9: Firebird - whole tree
Mary Meyer Photo 10: Louisa close-up
Mary Meyer Photo 11: Louisa - whole tree
Mary Meyer Photo 12: Pink Spires close-up
Mary Meyer Photo 13: Pink Spires - whole tree Which one would I plant in my yard? Anyone from this list, but something in the name 'Professor Sprenger' does resonate with me! It is a lovely tree that greets visitors on the Snyder Terrace at the Arboretum. Others you can see easily at the Arboretum are: 'Donald Wyman' planted in mass in the first parking lot bay across from the Oswald Visitor Center; 'A…

The BEST Crabapples for Minnesota: Height, Fruit, Scab Resistance and Finally: Flowers - Part I

Mary Meyer
Photo 1: Prairie Maid close-up
Mary Meyer Photo 2: Prairie Maid - whole tree
Mary Meyer
Photo 3: PrairiFire close-up
Mary Meyer Photo 4: PrairiFire - Whole tree (left) Sargentii espalier (right)
Mary Meyer
Photo 5: Professor Sprenger close-up
Mary Meyer
Photo 6: Professor Sprenger - whole tree
Mary Meyer
Photo 7: Red Jewel close-up
Mary Meyer
Photo 8: Red Jewel - whole tree
Mary Meyer
Photo 9: Royal Raindrops close-up
Mary Meyer
Photo 10: Royal Raindrops - whole tree
Mary Meyer
Photo 11: Sargentii close-up
Mary Meyer
Photo 12: Sugar Tyme close-up
Mary Meyer
Photo 13: Sugar Tyme - whole tree Mary H. Meyer, extension horticulturist and professor, University of Minnesota

This summer I was asked so many times "What is wrong with my crabapple?" that I started LOOKING anew at crabapples. 2014 was a banner year for apple scab, discoloring the foliage and causing premature leaf and even fruit drop. Affected plants looked dormant, or as many homeowners feared, d…