Jan I am no expert on everything, and an expert on nothing however I am tempted to hazard a guess that the problem you are having might relate to the fact that your soil is clay, and perhaps not the pH which might be amiss here. Perhaps its too late in the season now for you being so much further south them but I would be tempted to carefully dig up one part of the clumped stock as an experiment, VERY CAREFULLY, and prize away what you safely can of some if not all the clay then replant the material either in a very large pot, say 10 litres, or replant back into a 50:50 mix of course builder's sand and gravel along with composted leaf mould or similar (they clue is in the Latin name 'sylvestris' meaning forest associate or likeness) followed in either option by well watering them in for several days to reduce the shock. It is more probable than not, as with Lilium that the Tulipa will have determined already whether it is going to flower or not and you will be not be further forward this year in that sense but nothing tried nothing gained. However if you suspect that the probability is that they will remain blind again what have you to loose. I checked our Tulipa sylvestris earlier today to see where they had reached and they are not far out of the ground here, c, 10-12 cms at most. These plants are in our rockery which receives free lime applications bi-annually and it is otherwise composed of course sand and gravel with precious little humus but the lime needs regular additions due to easily being leached out. This Tulipa is a long way from its natural distribution in Europe from where we live but perhaps you could check the distribution of it in Flora Europea the cross reference that with your relevant geological maps and try for creating an analogue of some sort. Best of luck and I would be interested to learn how it works out, this year and next. I might curse my granite sands and gravels that pass for a soil of sorts here but am eternally grateful we don't have clay. Iain -- I am using the free version of SPAMfighter. We are a community of 6 million users fighting spam. SPAMfighter has removed 67612 of my spam emails to date. Get the free SPAMfighter here: http://www.spamfighter.com/len/ The Professional version does not have this message