Glads for hardiness

Jim McKenney
Tue, 06 Mar 2007 09:47:17 PST
Those of you expressing outrage that some commercial growers keep their
fields clean by deliberately growing plants not likely to survive the winter
should perhaps review the history of the tulips known as thieves. Those of
you who grumble about receiving mixed stocks are perhaps receiving goods
from growers who don't have such scruples with respect to keeping their
growing fields clean.

The hardy gladiolus question has long intrigued me, too. But the focus on
hardiness as such seems misplaced to me. What I would like are gladiolus
which capture a broad spectrum of the morphological variety seen in the
species not well represented in cultivation in plants which will be reliable
summer growers in the northern hemisphere. From my perspective, the most
important goal is to get them permanently switched over to the northern
hemisphere summer - innate hardiness can come later and in the meantime
there are simple ways of protecting winter dormant plants.

As several people have already pointed out, the large hybrid glads are
hardier than they are often given credit for. Many clones will survive zone
7 winters with the merest protection. That they eventually disappear might,
as Boyce suggests, be due to rodent predation. But I suspect that there is
another cause: the rapidly replicating corms are pushed up to the surface
where they are exposed to harsher winter conditions. 

Awhile back we had a discussion of Gladiolus, and among the species
discussed was G. tristis. I think it was Mary Sue who spoke of early
flowering and late flowering forms. I was excited to hear her mention a late
flowering form: I though this might be the solution to growing this species
here in the garden.   

Unbeknownst to me, I had a plant of Gladiolus tristis in my cold frame at
the time. I don't know if this corresponds to Mary Sue's early or late
forms. But this plant is not the answer to my quest for a garden worthy
Gladiolus tristis: it is a confirmed winter grower. Last year it revealed
its identity when it bloomed in mid-April. It's beautiful and I'm happy to
have it, but it's obviously not a garden plant.

On the other hand, if it had turned out to be a form which began to grow in
April rather than the one I have which starts to bloom in April, then I
would have been able to establish it as a garden plant here. 

So I say the focus should be on growing season, not cold hardiness.
Obviously we need both eventually, especially for those north of zone 7.  

Jim McKenney
Montgomery County, Maryland, USA, USDA zone 7, where ugly, brutal winter has
returned with howling winds, bone chilling wind chill factors and frigid

My Virtual Maryland Garden
Webmaster Potomac Valley Chapter, NARGS 
Editor PVC Bulletin 
Webmaster Potomac Lily Society

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