Re: Delph Replys replys

At 4:17 PM -0500 11/22/98, LONDE@aol.com wrote:

> In a message dated 98-11-22 12:06:33 EST, LONDE@aol.com writes:
>
> << From: Peggy Enes <peggy@unicom.net>
> Peggy, Yes, the blue butterflies are less fussy than the giant delphs.  The
> giant delphiniums are going to fry in full sun, as yours did, in a hotter
> midwest summer even if they are mulched.  My experience is that you are only
> going to be successful
> with them in the midwest if the summer is a mild one, or if they are in
> partial shade.
> Mulch alone will not protect them.  They can not take extended periods of hot
> midwestern sun.  The safe way around that is growing them in part shade here.
> They do best in full sun where the summers are not so extreme, but If you put
> them in full sun here, you are gambling that it will be a mild summer.

I admit nine plants isn't much of a test but dead plants, mulched in
full sun v/s living plants in shade with no mulch is enough to convince
me that afternoon shade is going to be a lot more critical than the
mulch to beat the heat.

> Sorry, Peggy.  I did not mean to type root rot.  They are susceptible
>to crown
> rot.

I saw "root rot" and thought, "Oh @%$#, not something else to
complicate matters." :) Root rot in the dead of summer was a new one to
me. I thought maybe the delphs were extra sensitive to even very small
soil level changes the way some trees are.

> Sorry to confuse you.  Either way, the issue is not the build up of rotted
> organic matter or how fast the mulch breaks down.  Any type of mulch around
> the crown of a delphinium can creates two problems -- 1) Mulch holds moisture
> in the soil.  If too much surface moisture is held near the crown it will
> promote crown rot.  Delphiniums can't take wet feet in a climate like ours.
> 2) Mulch is a good hiding place for slugs to which delphs are also
> susceptible.

I've read that delphinium are prone to fungal disease so I thought
generous spacing would be important in our hot/humid summers for good
air circulation. The crown rot problem seems additional reason to do
so. It's a heck of a lot easier to keep the mulch well away from the
crown with wide spacing.

> Again, sorry for my mistake, it is not root rot, but rather crown rot.  But
> your point about fertilizer is a good one.  For this, and many other reasons,
> it is never a good idea to overfertilize any plant...

I was just speculating about a semi-plausible cause for summer root
rot. :) Thinking about it, though, makes me think doing a fertilizer
experiment next year with the Dowdswells might be more than well
worthwhile.

> That is why you have not had problems due to mulching.  My entire perennial
> bed is mulched in the summer.  I just keep the mulch away from the base of my
> delphiniums and other slug & crown rot susceptible plants.  I am especially
> careful not to mulch around delphiniums in the winter, because mulch during
> the dormant period is especially conducive to crown rot disease.  You are
> right, that is an interesting job!  --Janis

I've been told by several people that rotting is responsible for more
perennial plant deaths than the cold here in Kansas City because of
wet, early springs and heavy soil. I don't know, however, if that is
just their opinion or is based on good science. It does seem to make
sense.

Thanks for root rot clarification. Delphinium certainly seem
sufficiently challenging without borrowing trouble. :)



---
Peggy Enes (peggy@unicom.net)   Zone 5/6    NE KS     AHS Heat Zone 7


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