Re: Winter damage
Al -- I wish I could figure out the heaving phenomenon. Over a period of
10 years, I can't observe a pattern, but I think I have isolated a factor:
moisture in the soil.
I have more than 1,000 clumps located in my home gardens, and I have no
heaving problems there. (By that I mean that I don't think I've ever had
more than half a dozen rhizomes heave in a winter.) The soil is ordinary
turned turf with commercially-produced topsoil and sand added over the
years. Both adult plants and new sprouts are set into these beds as soon as
they are constructed, i.e., they are mounded up, covered with Preen, and the
Preen either watered in by rain or by me, whichever gets there first. My
gardens are about 20-25 feet above the level of the nearby tidal Potomac.
Although nearby construction has caused parts of some of my backyard beds to
flood 4 or more inches deep during hard rains, they drain overnight.
On the other hand, at my seedling gardens 4 miles away, which are probably
about 10-15 feet above Potomac level, I have been plagued by intermittent
massive heaving for the last 10 years. Intermittent is the key word here.
It doesn't occur every year. But when it hits, it heaves up whole rows of
well-established plants as well as new seedlings. Over the years, trading
up, I have used several plots comprised of very different soils-- from muck
soil to soil that's at least 50% rock, to rich, friable soil. It all
heaves. All the beds are raised several inches above ground level. But
when it rains hard, water remains in the aisles between the beds for 3 days
or more. This leads me to think that the soil is easily saturated and thus
is more vulnerable to the effect of freeze-thaw cycles.
Although you and I are located probably within 60 miles of each other,
you're at a higher elevation, I think, and it seems we had different
winters. I covered one of the seedling bed plots with 2 inches of 1/2 leaf
mulch and 1/2 sand. There was some heaving, but it probably affected less
than 5% of the plants. In another plot, as an experiment, I put an inch of
concrete sand on the beds, thinking it would sift down into the soil if
heaving began to occur. There was virtually no heaving there, but, even
though I removed the sand as soon as winter was over, I had a severe rot
problem in those beds. Twenty feet away, another plot with hundreds of
clumps had not a single case of rot. How I wish I knew what caused the
Now, getting to the fertilizer: I went back, this year, to my old 6-24-24
as a top dressing, which I have to mix myself because you can't get it on
the East coast. The iris loved it! To me, 10-10-10 is too much nitrogen
and not enough phosphate and potash, although I know that some of our iris
growers say it works fine for them.
I also put Merit on my beds for the first time this year. I've seen no
evidence of borer activity, so far, and very few aphids, but, more
importantly, I have no leaf spot to speak of this year!!! I don't know if
that's attributable to the Merit, but it's the difference of night and day
from the last several years.
I don't think feeding some Miracle Gro to your plants can hurt them. I'm
just not sure how much help it will be at this time in the growth cycle.
Hope all goes well with the vision, Al. -- Griff
zone 7 in Virginia
----- Original Message -----
Sent: Wednesday, June 01, 2005 10:10 AM
Subject: [iris] Winter damage
> We had a nasty winter for iris. Seventy five one day and 36 hours later it
> was 5 above. Warm, hot for awhile then a week of cold and wet weather.No
> cover. I guesstimate 75 % of the bearded iris heaved up. I pushed them
> and reset as I could. The next week or so they are back up. Some I
> rocks on the rhizomes, but I'd need a ton rock.
> This spring I reset iris that had heaved. Fertilized with 10,10,10 and
> placed merit for borers. Most responded to the fertilizer. However so
> reduced to one small rhizome.
> What damage would I be dousing if I gave all the bearded a watering with
> reduced Miracle Grow. One 1/2 TBS per gallon.
> Al Bullock
> Northern Virginia Z7
> PS I can spell I just can't see too well. Cataract surgery! ;>)
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