In an e-mail to Daffnet of April 9 I wrote that I lost many daffodils by frost. Now I have some further details, but the whole dimension of the damage is not yet to be seen, because I dig out only bulbs which stood for 3 years at the same place . It was the first time for me to loose daffodil bulbs in winter, a quite new experience. In the first part of the last winter it was very warm with no frost. You see in the picture,taken at January 27, N. cyclamineus is short before flowering.The ground was extremely wet from rain during January. I have a heavy soil which takes a maximum of 540 g water by 1 kg soil. The draining is not optimal. From January 28 to February 14 a period of frost followed, the temperatures went down to -14 degrees C. The ground was frozen during this time up to about 40 cm and without snow.
Destroyed were the bulbs of N. cordubensis, N. henriquesii, N. tazetta, N. bulbocodium of commerce, bulbocodium crosses ( N. bulbocodium x N. romieuxii), Smarple, Emerald Sea, Hawera and many of my seedlings. Many standard daffodils which flower early were totally destroyed or badly damaged: Especially 2 Y-R daffodils and yellow trumpet varieties. Daffodils with many poeticus genes which flowered late were nearly not influenced. This was so too for many 2W-P and 2 W-WWP, as for example Ken’s Favorite, Assertion, Presidential Pink, Savoir Faire and Show Band. Most fertile jonquilla hybrids which are early with their leafs, for example Regeneration and Limequilla, stood the frost well as did Sun Disc. The flower buds of some varieties for example Sidley were empty, that means without flower.
The damage was variable for different places in the same field. In places with some shade which were a little colder and where the leafs were not so big the daffodils were not so hardly affected as in spots with full sun.In little sunken spots in which water could collect the bulbs were especially harmed. In fields of the neighbours with sandy and/or sloping ground the damage was much less.
In detail the process of destruction for standard daffodils followed a special sheme: The leafs were much or more affected and the roots were damaged or destroyed. With no roots the big leafs got no water after the frost period and died down. In some cases the bulbs survived without roots and leafs but lost weight and became smaller. They will need one or two years to flower again. In many cases the rotted roots infected the basal plate of the bulb and afterwards the whole bulb decayed in the wet soil.
That are the facts. The deeper cause of the destruction is not so easy to explain. Some factors may have influence:
- The resistance of different varieties to frost is unequal.
- The daffodils had no time to acustom slowly to the falling temperatures. There was an extremely warm period and then they were ‘shock-frosted’.
- In the wet soil shiftings of soil plates developed by frost which broke the already very long roots.
- The wet soil after the frost period promoted the rotting of the damaged roots and bulbs.
Many of you should have comprehensive experience with the influence of frost on daffodils. Perhaps you have some more or quite other explanations.
Theo
Hi Theo.
Very interesting material about frosts. We get moderate to heavy frosts here but I have never lost anything – note though that we are growing standards except for a collection of minis which Lesley grows in pots. I have noted a small amount of damage on jonquilla hybrids and of course burnt tips on the foliage of many others. If a really heavy frost is forecast then I will put frost cloth over some varieties.
Great to hear that you are coming to NZ for the World Convention. We look forward to seeing you in Dunedin.
Cheers,
Peter