Moraea tricolor corms not sprouting -2 years

Michael Mace
Thu, 16 Nov 2017 08:59:06 PST
Sarah wrote:

> I have two corms of Moraea tricolor that are not sprouting.  

It's surprisingly common for Moraea corms in cultivation to "take a year
off." It happens even in warm-summer places like San Jose (where I am). You
think they've died, then dig them up the next summer and find that the corms
are just sitting there unchanged.

Very often I'll have a pot with six or more corms, and only a couple of them
sprout each year. Often they'll grow just fine the next year. I've never
been able to figure out why they take vacations like this.

One thing I do worry about: Because those M. tricolor corms have a thick
corky tunic around them, you don't know what's happening inside. Is the full
corm intact under the tunic, or is it dwindling away during the off year?
The only way to check is to break the tunic to look inside, but if you do
that I worry that you'll injure the corm itself. So usually I just put them
back in the pot and hope.

Colin's ideas make a lot of sense to me. When in doubt, give the corms
conditions that are as similar as possible to their native habitat.

In old gardening books you see people talk about "ripening" corms. That
means leaving them out of the ground in the summer so they get some heat and
dryness. For example, there's an article from the early 1930s here:…

The authors concluded that different ripening schedules for hybrid Gladiolus
corms made a significant difference in the nutrients stored in the corms,
but didn't change their flowering behavior the next year. However, those
were hybrid corms bred for vigor, and the authors speculated that the corms
stored so much excess food that they could cope with any sort of treatment:
"Usually a gladiolus corm may be considered to have huge reserves of energy,
only a portion of which is needed to establish and maintain the new plant."
You're growing species that have been through much less breeding than those
hybrids, so I can imagine that a small difference in their culture might
change their behavior.

A more recent reference says that Freesia corms are "prepared" while dormant
by storing them for 12 weeks at 30 degrees C (86F) and then giving them a
cool period to stimulate bud formation.… 

The trouble is, not all Moraea species come from the same part of South
Africa. What stimulates one species might cook and dry another to death. So
you may have to experiment a bit.

Good luck!


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