Flower Formation (cross posted on "that other list")

Joe Shaw jshaw@opuntiads.com
Sat, 12 Aug 2006 09:55:26 PDT
Flower Formation

Irrigation for garden Crinum is great.  Sometimes languid clumps can 
suddenly bloom in the month following heavy rains.

Many bulbs form flower buds a long time before they are stimulated to bloom, 
perhaps during the prior growing season or even the one before that.  So, 
for me, the key to good blooming has been regular watering over a long 
season of growth, and every season.  This means that I water the plants if 
it hasn't rained in 5 days or a week (during hot weather); I water potted 
plants a lot, even if they are in 25-gallon containers.

By nature, many bulbs don't perform their best in their natural 
environments, or they may not do so every year.  They have bad years and 
good years, and grow and flower accordingly.  Typically, if care is taken to 
make sure they are not pushed too hard with fertilizer, many bulbs will 
perform best in gardens where conditions are better than they might ever 
experience in nature.

There can be drawbacks sometimes plants that are grown "hard" have a special 
look, a durability and presence that is often lacking in garden-grown 
plants.  Also, garden-grown plants may suffer from too much fertilizer, or 
exposure to insects and pathogens not encountered in the wild. 
Additionally, plants that are pushed to grow for months on end may have lots 
of new growth that is sometimes fodder for nearly permanent pest 

For the most part, garden bulbs are a hardy lot, and are often hybrids that 
might not even be able to survive or reproduce in "the wild."  So, I'm happy 
to push my flowers with water, and Crinum types seem to appreciate it 
(during the growing season).

Some plants need a down time, a stress- or environmentally-induced (drought, 
short days, cold, heat, etc.) period when they shut down.  They may not need 
such period to actually survive but may require it for flower bud formation 
or maturation.

Many Crinum like to slow down during the winter, but that can be a problem 
in many gardens; sprinklers or year-round rain don't permit the type of 
drought that is experiences by many bulb species in the wild.  For instance, 
Amaryllis belladonna grows easily here in my yard, but it has never 
flowered; I'm pretty sure it needs a pronounced summer drought.  Similarly, 
Lycoris squamigera grows easily here; alas, it too never flowers.  The 
leaves pop up after January and die down by June; I think it must need a 
period of cold to flower.  The local rain lily (Z. chlorosolen) blooms 
reliably, but the flowers are unnaturally tall and can fall over-perhaps too 
much fertilizer in the flowerbed.

Anyway, getting back to flower formation, I take care to water Crinum for at 
least six months of the year (March-September); they enjoy it.  C. scabrum, 
C. delagoense (sthulmanii), something that seems like C. graminicola, and 
some others just deal with the rain as long as they have deep soils and good 
drainage.  I try to remember to put pots of the latter 2 species on their 
sides for winter.

Conceptually, I lump many bulbs (Crinum, Nerine, Lycoris, some Tulipia, 
etc.) into the same category I put succulents.  The bulbs are indeed adapted 
for drought, but like succulents need water.  The amount of water, the 
timing, the drainage, and so on are all variables that might be  modified. 
For instance, I plant most cacti in pure scoria (lava rock for landscape). 
Then, I pour a little soil into the rock cracks (the soil is a mix of sand, 
perlite, and 10% humus).  I never water cacti, they get far more rain than 
they need just by being here in the Greater Houston area.  Even with a soil 
composed primarily of scoria, I still have to apply fungicides 2 or 3 times 
a year to be sure the roots don't acquire some infections.

After thinking it over and getting some advice from Greg Pettit, I've 
decided I'll move the C. delagoense to a mixture that is composed of more 
sand and perlite, and far less humus.  Maybe that will make them happier 
with year-round rain, maybe not.

Back to flower formation:  typical bulbs like water in the growing season; 
typical bulbs like good drainage.  Many bulbs seem to produce flower buds a 
long time before we ever see the flowers and I try to help them along by 
giving them lots of water during the growing season.



Conroe, TX

Not too hot today, not a lot of rain this week.  I've watered the Crinum 
beds twice this week, and of course, have given no water to the cacti.

More information about the pbs mailing list