Hi John, that's sounds a bit worrisome with Lankon.
My climate probably differs quite a bit from yours, but for what it's worth I can tell you that my Lankons started emerging in February - we did however have an exceptionally mild winter. The Lankon bulbs were planted late in April 2014 in a fairly protected and warm site, so were well established. I assume they would be later to emerge had they been autumn planted. As a reference the latest of other established lily varieties have just poked their noses above the ground a week or two ago.
But of course one shouldn't abandon hope to early. Last year I had a couple of spring planted orienpets that refused to show. I carefully dug down beside them only to find sprouts that had started to grow a bit and then died. The bulb was still firm and nice. This year they are back
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