Winter Hardiness Trials of New Garden Chrysanthemum Varieties and Farm Research on Effectiveness of Winter Mulching Techniques

Final Report for FNC05-550

Project Type: Farmer/Rancher
Funds awarded in 2005: $6,000.00
Projected End Date: 12/31/2007
Region: North Central
State: Michigan
Project Coordinator:
David Coveyou
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Project Information



Coveyou Scenic Farms is a family farm in northern Michigan. The farm focuses on a diversified direct-marketed model to take advantage of the tourist destinations of Walloon Lake and Petoskey. Garden Chrysanthemums are grown by many farm operations that are transitioning into the direct marketing of farm-raised products to the general public. Fall garden mums are by far the largest selling fall flower and are used extensively for landscaping and home decorations throughout the country. Small farms including our farm, Coveyou Scenic Farm, generate a significant portion of their fall business from growing potted garden mums for direct retail sales.

Garden mums have become known as “Hardy” mums because of their ability to withstand significant growing stresses (lack of water, light frosts, etc.) and their historic ability to often live through the winter even in some northern areas of the country. Garden mums are technically not classified as a perennial with an associated USDA winter hardiness zone published.

Over the last ten years there has been an explosion of garden mum varieties introduced by plant breeders. Our research and discussions with breeding companies reveals that much of their focus is on producing plants that have a larger round habit, increased free branching with more flowers, a wider range of colors and better flower color keeping qualities. Winter “hardiness” does not appear to be on their list of characteristics that they monitor or breed for in their garden chrysanthemums.

Many garden mum consumers desire to know which of the dozens of available varieties have the best winter hardiness and desire to get detailed technical recommendations on how best to attempt to protect their mums from dying out over the winter. We feel that if we could educate customers on varieties and overwinter techniques for our northern regions we would be able to increase sales at our farm. People are looking for this information but our research has not uncovered any solid data to support any recommendations. We believe farmers who grow and market mums for northern areas would benefit both technically and financially from this work.

Furthermore, it has been stated in some grower circles that garden mums grown in commercially available recycled cardboard pots may actually have better winter hardiness when planted directly in the ground in their pots. The recycled cardboard pots will decay with moisture and time but when planted late in the fall may provide some level of insulation to the root system during the winter prior to the pot fully decaying. We can find no data reported that has explored this theory. Recycled cardboard fiber pots are commercially available and only slightly more expense than commonly used plastic containers.

Work Performed: We executed our plan to test the winter hardiness of a wide variety of garden mums by performing overwintering trials on our farm. Fifty varieties of garden mums grown at Coveyou Scenic Farms in 8” fiber pots were planted in the variety winter hardiness trials. A test plot field was prepared with soil cultivation through plowing and disking. A weed matting material was put down over the test field and secured in place. Holes were cut in the matting to allow plants to be spaced 24” on center in rows and between rows. Drip irrigation lines were run to water each plant individually and identically. The irrigation system was tied into our larger farm pond irrigation pump system. Six representative mum plants from each selected variety were planted into the test bed with three of the plants having their fiber pots removed and three planted directly into the ground with the recycled cardboard fiber pot as described in our original plan. Planting took place from September 8th through 16th. The following picture shows the winter hardiness test bed.

[Editor’s Note: To see the photo, please contact NCR-SARE at: [email protected] or 1-800-529-1342.]

Monitoring of the plants for insect, fertilization and other concerns took place from the time of planting through the end of the year. In mid-November straw mulch was placed over all plants in this test plot.

The following spring the straw mulch was removed and the plants allowed to grow naturally. We documented the survival rates after time was given for all plants to emerge.

For the second part of our project plan we took three mum varieties that we believed to have reasonable winter hardiness and planted them into the above trial bed with 18 plants of each variety. Six of each of these plants would test various mulches applied to them for the winter (i.e. 6 plants with hardwood tree leaves, 6 with 18” of snow piled high on the plants, 6 with no mulch applied). The survival rates of each mulching method were determined.

All plants appeared to root in well and none experienced any stressful situations. Our abnormally early snowfall in mid October did no harm to the planting. We accumulated 15-18” of snow by early December only to watch an unseasonably warm latter half of December melt all the snow. January and February were seasonably cold with many days of very hard freezing. The unseasonably warm December and lack of snow may have skewed our tests because of the lack of snow and following hard freezes. In a more normal year the plantings would have had more natural snow cover prior to the hard freezing temperatures.

The survival rates were documented during the growing season of 2007. Data was collected on plant survivability for plants rooted directly into the soil as well as plants that were planted in their fiber pots. Note that three plants of a given variety were planted with the fiber pot and three plants were planted directly in the soil with the fiber pot removed. Only 22 of the 50 varieties planted had one or more surviving plants. The Yoder variety Bold Gretchen performed the best with 4 of the 6 plants surviving the winter. No varieties had all plants survive. Many varieties had no plants survive.

It is also interesting to note that plants allowed to root directly in the soil survived better than flowers planted in their fiber pot. Specifically, 28 plants survived planting directly in the soil versus only 12 when planted in their fiber pot. It is interesting to note that not all varieties performed similarly. The variety Hankie had all three of the flowers planted in their fiber pots survive, however, none of the flowers planted without the fiber pot survived. Cessaro and Hanah were two other varieties that each had a single fiber pot planted flower survive but none of the non-fiber pot planted versions made it through the winter. On the whole we would still draw the conclusion that planting without the fiber container is the better practice if one desires to maximize winter hardiness. The list below shows all of the surviving varieties and the percentage survival rates.

[Editor’s Note: The following varieties survived the trial: Bold Gretchen, Helga, Victoria, Sunny Gretchen, Hankie, Barbara, Golden Helga, Marjorie, Tabitha, Mellisa, Verselli, Sunny Camiel, Fiona, Milano, Hanah, Golden Marylynn, Brandi, Golden Cheryl, Jessica, Heather, Courtney, Cessaro. For copies of the list with survival rates, please contact NCR-SARE at: [email protected] or 1-800-529-1342.]

The following list shows all of the varieties tested in this winter hardiness trial and how they survived.
[Editor’s Note: The following varieties were used in the trial: Alexis, Barbara, Bold Gretchen, Brandi, Camina, Carrie, Castildo, Cessaro, Christine, Courtney, Dark Veria, Dazzling Stacy, Delightful Victoria, Emily, Erica, Fiona, Frimo, Galitino, Glenda, Gold Crest, Golden Cheryl, Golden Helga, Golden Marylynn, Hanah, Hankie, Heather, Helga, Jennefer, Jessica, Marjorie, Mellisa, Milano, Miranda, Nancy, Natalie, Novare, Padre, Red Tempress, Savona, Sherry, Sunny Camiel, Sunny Gretchen, Tabitha, Terano, Urano Red, Verselli, Victoria, Warm Megan, Yellow Cilano. For the list of all varieties tested with survival rates, please contact NCR-SARE at: [email protected] or 1-800-529-1342.]

A second portion of this project was to explore the impact of various mulches on the winter hardiness of fall garden mums. In the experiment six plants of the same variety of garden mum were planted in three individual beds. Three of the plants were planted with their original fiber container and three had the container removed. A total of three varieties were planted in each bed. One bed was mulched about 8” high with uncompressed leaves. A second bed was intended to have snow piled deep on top of the plants to provide insulation, however, due to the nature of this year all of our snow melted prior to the harder freezing weeks. This may be a good testament to the risk of using snow as mulch for protecting plants. The third bed was left uncovered as a control. The survival data is shown below.
[Editor’s Note: For a copy of the survival data, please contact NCR-SARE at: [email protected] or 1-800-529-1342.]

It is hard to draw any firm conclusions from this data. Considering the “Piled snow” bed was for all practical purposes the same as the control bed with no mulch it is hard to see significant differences in survival rates due to mulching method or mulching at all. This data is not conclusive since in a different year the coldest temperatures could be more severe and the mulch may play a more significant role.

We believe this 2006/2007 winter weather or other factors may have presented some anomalies that have skewed the winter survival rates of garden mums. On the whole we do not expect such poor survival rates. Our plan for the 2008 season is to retrial a number of varieties to see if we can observe a more reasonable distribution of survival rates. In the meantime we would recommend the varieties that survived as being some of the more hardy varieties for northern climates.

This project and our larger farm operation were highlighted during a summer tour by Michigan extension agents as well as Michigan State University Product Center representatives. This walking tour as well as discussion session was able to inform some of the key facilitators of growing and sustaining Michigan agriculture of the work taking place on our farm.

Furthermore, the results of this trial have been shared with many avid gardeners and homeowners who were looking for more winter hardy varieties of garden mums this fall. Our farm is one of the largest farm market grower and retailers of garden mums in this portion of the state and we were able to use the results of this project to inform many individuals of this project and the results we obtained.

We are hoping that our results of the 2008 retrial will lead to significantly more survival rates and allow us to combine the multiple year findings into a summary with strong enough results to warrant acceptance at the 2009 Michigan Small Farm Conference.


Participation Summary
Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.