freezing? an alternate to HWT?

June 20, 2008

Categories: Bulb Information, Growing Daffodils, Species

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From up here in the far north where the ground freezes solid up to 6 feet deep:

Much research has been done on cold hardiness in plant materials in my neck of the woods, Minnesota.  Those of us in the Daffodil Society of Minnesota have had significant bulb losses because of our extremely cold winters which do kill most of the other organisms plaguing daffodil growers in warmer climates.  We’ve had to learn the hard way, I guess, by trial and error.

That said, there is a scientific regimen which preserves most varieties of daffodils through freezing temperatures (exceptions being Tazetta, Poetaz, Bulbocodium and descendants thereof, and most of the Mediterranean species Narcissus).  We here in Minnesota stress the need to plant early (by Oct. 15th) and water the bulbs to stimulate SIGNIFICANT root growth before our ground freezes (usually just after Thanksgiving).  The roots do two things:  (a) remove some of the water from the bulb tissues and (b) convert the remainder of the water to a carbohydrate-like substance which has a much lower freezing point—anti-freeze!  This process happens normally in the cold hardy plants for our Zone 3-4 State.  Unlike actively growing Minnesota hardy plants, newly planted DORMANT bulbs have not had the benefit of late summer rainfall (if we get any, that is!) and shortening daylight hours to provide a cue to start this freezing-temperature preparation.  Without this root growth, our bulbs are like Bob’s mush in the spring—heart disappointing “no-shows.”  The water in the bulb has frozen into ice crystals which expanded and burst the tissues.  Also, bulb varieties that are stressed by digging, molds or moisture during summer storage sometimes are unable to produce adequate roots to survive our punishing winter climate.   Bulbs coming from high water table areas often have to be planted even earlier to give them time to deal with the excess water in their water-plumped tissues; after a Minnesota winter, the “fat” bulbs will slim down to what we call “normal” size.

Another issue that I’ve discovered the hard way:  Shipping bulbs to Minnesota in late fall is not worth it.  (Nightime temperatures can fall below freezing as early as late September!)  They apparently freeze during the airplane ride or the ride in the UPS/FedEx truck—à la Bob’s malfunctioning refrigerator.  For the past two years, I’ve tried to save a few bucks by waiting for Brent & Becky’s clearance prices to purchase a few things to pot up for wintertime enjoyment in the conservatory.  Results have been disappointing:  few bloom well and some don’t make it at all!  This also happened to the couple of items I purchased from last autumn’s Fall Board Meeting auction which George Dorner kindly shipped to me.  The only solution is to hand carry the bulbs back from the auction—which means I have to attend  Nashville and order early!

I hope this gives some guidance to newbies who might otherwise be puzzled why they haven’t been successful.

Edie Godfrey

Minnetrista, Minnesota


One response to “freezing? an alternate to HWT?”

  1. Merrill Jensen says:

    I’d like to also confirm these observations from further north Alaska.  Here at the Jensen-Olson Arboretum, I newly planted 500 daff’s last fall.  The order from Brent & Becky’s arrived in late October and the bulbs hit the ground soon after.  Our first really hard freeze came the first week of December with no snow cover. (we hit -4 degrees f). ‘Segovia’, ‘Stint’, ‘Sun Disk’ and ‘Hawera’ (which is still in bloom now…) all did fine.  ‘February Gold’ and N. nanus var. lobularis took some sever hits.  Only a few bulbs each managed to bloom….  I’ll be putting together a new order for this coming fall soon and will add to the numbers of the cultivars that did well and will skip ‘February Gold’ all together.


    Other bulbs that were donated to us late from one of our local nurseries had similar disastrous results.  I planted a lot of Iris reticulata and Anemone blanda in mid- November and only had a few of each show up this spring.  For us in the colder realms of the planet, early fall planting is certainly the way to go.


    Merrill Jensen

    Juneau, Alaska