your opinion please

[Catwheazle]

Hi, I need an advice from our "crocus specialists" here:
In my garden there are from earlier (previous owners), because of a mixture from the garden center, various botanical crocuses.
Most common are tommasinianus ("normal" and "Bobbo"), sieberi tricolor, but also chrysantum (Ard Schenk and Cream Beauty), korolkowii, fleischeri and ... and here I see a problem: vernus (the big Dutch ones) and vernus ssp. albiflorus, which is also in the wild here, at allgaeu. Others that I bought are in the pot.
My question: are there certain varieties that I should remove so that I don't have a hybrid mixture at some point?
vernus are only 2 specimens, also korolkowii and chrysanthum are only a few. tommasinianus is almost everywhere (rising tendency, like weed) and sieberi is also increasing.
What advice can you give me?
I would like to plant additional fleischeri,  "albiflorus" should also multiply. The big vernus (Dutch) ;-) seem to be sterile.
Thanks for your efforts
Bernd

[Janis Ruksans]

Some Dutch vernus are not sterile and seedlings are better than original varieties because they are virus-free.
From listed by you, hybrids can occur between tommasinianus and vernus (including both - former albiflorus and Dutch)

[Catwheazle]

Thank you for the feedback :-)
What would you do in my place?
My "Dutch" vernus (Dutch) look - for me - virus-free. They are also smaller than the ones I know from other gardens
greetings
Bernd

[Janis Ruksans]

Check leaves of Dutch "vernus" when they will develop. If there are yellow segments - they are infected.

[Catwheazle]

Ok. Thanks
have to wait some days till leaves are more developed.
Today i could not detect yellow segments.
Bernd

[lavateraguy]

I dug into the scientific literature a couple of years back to try and make sense of the Crocus vernus complex (and biflorus and chrysanthus complexes) for the purpose of botanical recording. On the basis of old cytological work I concluded that the Dutch crocuses (excluding 'Golden Yellow' and 'Picturatus') are mostly triploids, tetraploids and aneuploids of Crocus neglectus. But there's a lack of certainty about the generalisation as the cultivars studied were mostly not the cultivars currently grown. (With modern technology GISH could be used to identify the parentage of the cultivars.)

Therefore I would expect a considerable degree of sterility in Dutch crocuses. But this can't be absolute, as new cultivars are raised. And old established populations, such as in some churchyards, display a range of variation that doesn't fit with a population of a few clonal cultivars.

Plants in some older naturalised populations also seem to be smaller than the Dutch cultivars so I speculate that these have a different origin - perhaps Crocus neapolitanus, Crocus vernus (albiflorus), or a hybrid swarm. (I've failed to track down any studies on the identity of the, for example, Nottingham or Inkpen populations.)

[Catwheazle]

<Plants in some older naturalised populations also seem to be smaller than the Dutch cultivars

i think i have such an older population....

Thanks for your answer, ill look closer to my plants.

Bernd

[lavateraguy]

i think i have such an older population....

Bernd

From your original post I'd guess that you have the local to you Crocus vernus sensu strictu (i.e. subsp. albiflorus). My understanding is that this can be distinguished from Crocus neapolitanus and Crocus neglectus by having styles shorter than the stamens, rather than equalling or exceeding them. But Stace's flora qualifies that with "usually", and I do wonder whether the two specimens of albiflorus I found in a larger population were really that.

To field botanists crocuses (and other early flowering "bulbs" like Galanthus and Narcissus) in Britain mostly fall into the "is that validly recordable?" category, but standards are changing, and over the last decade Crocus has been recorded more often. The only area to consistently divide the Crocus vernus complex into two taxa is South Lancashire, which has recorded an appreciable number (a couple of hundred?) records of albiflorus. Unfortunately there are probably 3 taxa involved - I've mentioned the evidence in support of the presence of neglectus, and 19th century literature documents the importation of neapolitanus. (The original 'Purpureus Grandiflorus' seems to have been neapolitanus; I'm wondering whether the name has gotten transferred to a neglectus cultivar in the intervening period.) If I recall correctly it was on the SRGC forums that I read that neapolitanus and neglectus are next to impossible to tell apart using morphological characters.