Leucojum aestivum and vernum

Brian Whyer brian.whyer@btinternet.com
Sat, 18 Dec 2004 08:36:23 PST
I am interested in this discussion on flowering times of the snowflakes
(can we now call the Acis separation Snowflakes?) and in particular the
reversal of flowering sequence, with the "summer", Leucojum aestivum,
flowering before the "spring" L. vernum with Jim in zone 5. I have
always been curious as to what triggers flowering of bulbs, particularly
the autumn flowering species, and how I might try and speed them up or
slow them down better as potential show exhibits. Not that I show much
L. aestivum is a wild plant not far from me in the Thames valley, near
the extreme of its range, where it is called the Loddon Lily, after the
tributary stream of that name feeding into the Thames. I grow it and L.
vernum, and L/Acis autumnalis in my garden, (alkaline soil) and in pots,
as I do several of the other smaller more tender species. L. aestivum
flowers some 4-6 weeks after vernum normally, although the leaves of
Aestivum usually appear first and with this relatively mild December are
at present ~2" tall, whereas L. vernum are < 1". With vernum the flowers
come well before the plant fully leaves out, with aestivum the leaves
are more or less fully grown by flowering time. Is this still the case
with reversed flowering in zone 5? My aestivum could be 'Gravetye Giant'
or not, usually more vigorous and robust than the type, as I think they
may be well mixed up in the trade. Similarly I understand the green or
yellow tips on vernum at times may vary on some forms, almost at much as
Galanthus 'Lady Elphinstone'.
Acis autumnalis grows well for me and increases vegetatively alongside
cyclamen hederifolium and crocus speciosus and zonatus (a weed for me in
the lawn), but rarely flowers. In pots I can flower it. Maybe it is the
soil type or maybe the moisture conditions at various times of the year
that make the difference, although I cannot guarantee they are all from
the same origin now, as I have tried various pots from plant sales
trying to get a more floriferous form. The best flowering of A.
autumnalis I have seen is at the RHS Rosemoor garden in SW England in
Devon, where it is almost frost free under trees on a slope with acid
sandy soil, and seeds around readily.
Acis nicaeense is easy in pots with minimal protection and flowers OK.
A. roseum is OK but I have suddenly lost it in the past, probably
getting it too wet. The other Acis I do not have enough of or have not
grown long enough to comment on.

Brian Whyer, Buckinghamshire, England, zone ~8
Narcissus 'Cedric Morris' is full in flower in a pot on the outside of
the kitchen windowsill this evening, but with 6C max and -7C min
forecast for tomorrow, with precipitation, it may need moving. The
pansies in full flower can look after themselves.

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