Snaps - Again!

A year ago, I reported the successful overwintering of snapdragon varieties in our high tunnel (zone 5b).  To make sure that this was not a peculiarity of our winter season, we did it again, and after a tougher winter (January through March temperatures averaged 17F, 10 degrees below the long-term average for this site), I feel confident that this is a good way of getting a jump on the spring cut flower season with this crop, thus getting two crops from one planting.  

We sowed the seed of two varieties, ‘Supreme Light Lavender’ and ‘Maryland White’ in the greenhouse on June 3 and July 3, 2014, and transplanted them to the tunnel about 5 weeks later.  The plants were spaced 9 x 9 in. in 4 rows per bed, and pinched at transplanting.  They produced a good harvest in the fall, and were then either left unprotected in the tunnel over winter, or covered with a low cover of spun-bonded material.  The covers were removed in late April, and we started harvesting in mid-May, about a month before new transplants in the tunnel would come into flower.The results, after 3 weeks of spring harvest, are interesting and encouraging. As indicated in the table, winter survival depended most on having a low cover over the plants. There were also significant varietal differences in survival, with ‘Supreme Light Lavender’ having nearly twice as many plants re-sprout in spring than ‘Maryland White’.

Table 1.  Winter survival and early yield per unit area in spring of two snapdragon varieties sown in early June and July, 2014. Plants were either left uncovered over winter, or protected by a low tunnel cover from November to April.

Low tunnel coverVarietyWinter survival, %Yield of stems per ft2
NoneMaryland White220.2
NoneSupreme Light Lavender692.0
CoveredMaryland White604.8
coveredSupreme Light Lavender906.8
Stat. sign.Cover****

Yields in the fall were 12 and 15 stems per ft2 for ‘Maryland White’ and ‘Supreme Light Lavender’, respectively. Early yields in spring depended on survival, obviously, and are shown in the table. If they follow the pattern of the previous year’s trial, we expect them to be about two-thirds of fall yields.

There was a trend for winter survival and yield to be better for the later planting, but neither was statistically significant. Taken together, the results of the 2013 and 2014 trials encourage summer planting of snapdragons in high tunnels, and with protection by low tunnels over winter, taking advantage of the additional early yield the following spring.
Give it a try!

For the results of last year’s overwinter trial, see the summer 2014 issue of The Cut Flower Quarterly, or look for my annual report on the Cornell Horticulture website.

Acknowledgements:  I am grateful for the excellent help of my assistants, Priscilla Thompson, Anna Enockson and Emily Burrister.  Financial assistance by federal Hatch funds made possible this work.

Photo: ‘Maryland White’ (in foreground) and ‘Supreme Lavender’ snapdragon, September 29, 2014.

Chris Wien


Chris Wien is recently retired Professor of Horticulture at Cornell University. Contact him at [email protected]