Colchicum luteum

Jim McKenney
Thu, 22 Jan 2004 08:20:35 PST
Thanks for the suggestions, Mr. Grimshaw. Botrytis is rarely a problem here
early in the year, and so far I have never noticed botrytis on any of the
late winter flowering bulbs. Colchicum luteum here blooms in February,
early or late depending on the severity of the winter. In the past, I've
always dug the corms and stored them dry for the summer. They are stored in
earth under frame lights to keep off rain. Both temperature and relative
humidity here tend to be high all summer, so much so that it's hard to keep
some things dry enough.

The procedure outlined above seems to work for a wide variety of summer
dormant bulbs. But not all. I had Fritillaria aurea last year for the first
time. Every bulb grew and bloomed. I was smitten. When the vegetative
growth died down, I checked the bulbs. They were plump and surrounded by
dozens of little ones. Success! Hardly: by the end of the summer not a
scrap was left alive. They had been stored as described above. Were they
too dry? Too hot? Fritillaria glauca and F. pudica gave the same results.
On the other hand, F. acmopetala and F. uvavulpis performed beautifully
under this treatment. 

One final thought on this thread. That business about putting Colchicum
luteum in the refrigerator was actually prompted by speculation about how I
might grow Delphinium zalil/sulphureum here. I had imagined that both of
these grow in alpine meadows with a brief growing season during snow melt
and then a dry period. But does it get hot? I'll take your word for it that
it does get and remain hot. And I'll spare the Colchicum the refirgerator
treatment. The Saxifraga on the other hand...

Has anyone out there tried the yellow Delphinium? It qualifies as a
geophyte. We have Delphinium tricorne here as an element of the native
flora: it's a geophyte, too. It's a typcial spring ephemeral which grows
from a storage structure which suggests that of Ranunculus ficaria. 

Jim McKenney
Montgomery County, Maryland, zone 7, where things are apparently going to
thaw out for a few hours today

At 07:07 AM 1/22/2004 -0000, you wrote:
>Jim McKenney is suggesting putting Colchicum luteum into the refrigerator
>after it has gone dormant. While I would never stop anyone experimenting,
>one needs to think how these plants grow in the wild. As I understand it, C.
>luteum has a huge distribution in Central Asia eastwards to Kashmir: all
>areas that have a long hot summmer quickly followed by cold winters. The
>Colchicums, I believe, emerge as the ground melts and do their thing quickly
>before the summer heat comes on. The point is, however, that a long hot
>summer is experienced, and I suspect that this is necessary to the plant's
>physiology to trigger the initiation of new buds etc. It may well be
>disrupted if the bulbs receive too long a chilling, especially at the wrong
>time of year.
>In the UK C. luteum has a reputation for being difficult to grow, and being
>a martyr to botrytis. What happens is that they are planted in autumn and
>watered like other bulbs. We have no cold weather worth mentioning (these
>days especially) and the poor things come into flower in December, elongated
>in the low light so they look quite terrible. Then the flower fades and
>flops onto the foliage, and promptly develops botrytis, encouraged by the
>high atmospheric humidity. This spreads into the foliage and in no very long
>time, the plant is dead. To get round this I leave my pots of C. luteum and
>C. kesselringii (another C Asian species) dry from the time the plants go
>dormant until January, and repot them then. I did it just last Friday, 16
>Jan, this year. The bulbs have a fringe of embryonic roots and the shoot is
>well developed, so as soon as they are watered (as they would be with snow
>melt in the wild) they develop rapidly and will be in flower within the next
>few days. The growth remains compact and the plants grow with increasing
>daylength and warmth. Botrytis remains a problem, but is much less so than
>earlier in the winter. I have been growing C. luteum from Kashmir since 1989
>and from Tadjikistan since 1991 (also C. kesselringii) so these 'difficult'
>species can be maintained for a reasonable length of time. The biggest
>problem with this method is to keep the plants growing long enough to build
>up a decent new corm; a touch of dryness in about April will send them
>promptly to dormancy. This obviously happened with mine last year, as they
>are smaller than I really would like to see, but they're now back under my
>What I would suggest is that the bulbs could be potted in autumn and allowed
>to make some root growth, but are then put into cold storage until the
>spring or late winter. But it would have to be cold, 1-2 deg C; any warmer
>and they will grow!
>John Grimshaw
>Dr John M. Grimshaw
>Gardens Cottage
>Nr Cheltenham
>Gloucestershire GL53 9NP
>----- Original Message -----
>From: "Jim McKenney" <>
>To: "Pacific Bulb Society" <>
>Sent: Thursday, January 22, 2004 2:37 AM
>Subject: Re: [pbs] Five favorite yellow-flowered geophytes
>> Here's what I'm about to try for Colchicum luteum and, should I be able to
>> acquire another one,  Iris winogradowii: after the plants enter dormancy,
>> I'll give them a few weeks at prevailing temperatures and then  try
>> them in the refrigerator for the rest of the summer. The refrigerator here
>> gets opened so many times a day that the temperature is probably in the
>> 40s F much of the time, if that.
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