Bulb Log 35 - 29th August 08

[Richard Green]

I was interested to see that Colchicum/(Merendera?) flowering just now in Aberdeen.  We were in the Picos de Europa in early July this year, and I spotted what I first thought were crocus seed pods in the turf but they were clearly Colchicum on close inspection:


A couple of days later we saw that the first flowers were appearing amongst last year's seedpods- the turf would presumably be carpeted in flowers only slightly later on:


But all this was in the first week in July, and my initial thought is that neither day length, nor temperature differentials would entirely account for an early July flowering time in Spain, and end of August in Scotland.  So maybe water is the important factor given that June and July were wet in Spain.  Of course it is probably a combination.  Does anyone know better?

[Ian Y]

Richard welcome to the forum.
There are many factors that come to play that affect the flowering times of bulbs and they have always fascinated me.
I think that you are correct that water is a big factor however what we have to remember is that bulbs are masters of survival and have evolved to remain dormant in hot/ dry conditions and burst into growth when times are favourable.
What we have to consider is that a sudden wet spell will also cause the ground temperature to fall - so none of the factors can be taken in isolation.
The main factors that I believe to come into play are.
1) Clonal selection - the same species from different locations could well have evolved different flowering times.
2) Temperature. It could be an absolute temperature that is the trigger but I doubt that. I think it is more likely a temperature differential perhaps between day and night or just a sudden drop of average day temperature.
3) Availability of water.
4) Light levels/ day length may also have a direct as well as an indirect influence on some bulbs.
In the wild location and altitude come into play as they will have a bearing on the above list of parameters.

One thing I am sure about is that I am unlikely to know the answer in my life time but it will not stop me speculating, experimenting and being fascinated by all things to do with bulbs..

Great to see your pictures and I hope you will become a regular poster to our on line comunity

[Richard Green]

Thanks for the welcome - although I do not really feel new as I have been an avid reader of the Bulb Log for some years - if not a forum contributor.  I should not really be surprised that Iain has spent much more time than I observing and producing perceptive thoughts.  I shall be a wee while behind as the seeds I collected are only just being planted, and I need to get them germinating first.

My urge to put finger to keyboard came from the surprise with which I first saw the colchicum flowering in July in Spain reinforced by Iain's picture.  It really needs someone to do a serious comparison of temperature and rainfall factors with flowering times in the wild, and that in turn requires someone with detailed and consistent local knowledge of bulbs flowering in their native habitat over some years.  Just think what we could learn with that input!

[Maggi Young]

Richard, you are so right... so, what we need are forumists in Spain Turkey, Greece and all the other places where bulbs grow to get out and make these observations and report to us......

That would be terrific, indeed.... who is volunteering?
If the weather gets much worse here, I will offer to go live abroad myself and do as best I can with the project