What makes Amaryllis hybrids bloom?

John Grimshaw j.grimshaw@virgin.net
Tue, 25 Aug 2009 02:29:54 PDT
It is difficult to make useful comments on plants growing in other 
conditions, and without keeping detailed observations over a series of 
years, but here in the UK winter moisture is not a problem (!). What I think 
is important for any winter-growing bulb is that the foliage is able to 
expand and function to its maximum ability, enabling it to photosynthesise 
at the most efficient rate possible and thus build up the bulb. In a dry but 
essentially mild climate this might mean the effect of good winter rains 
enabling good leaf development: in a wet but chilly climate this may mean 
the avoidance of leaf damage by frost. It would be interesting to correlate 
Amaryllis flowering here with the severity of the winter preceding (or 
perhaps that should be winters).

The length of time a bulbous plant is in active growth is obviously 
important: if it dies down quickly in spring due to early drying-out of the 
soil it will not have been able to fatten up as much as one that stays green 
for longer.

When does Amaryllis normally go dormant for members in different parts of 
the world? I noticed yesterday that a patch of bulbs below a south-facing 
wall here at Colesbourne was still in full lush leaf (and thought that we 
aren't likely to get any flowers!), undoubtedly due to the persistently damp 
and cool summer we've had. I would normally expect them to be dormant from 
about June onwards.

John Grimshaw

Dr. John M. Grimshaw
Sycamore Cottage
GL53 9NP

Tel. 01242 870567

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