Re: CULT: non-blooming iris
- Subject: Re: [iris-talk] CULT: non-blooming iris
- From: l*
- Date: Mon, 27 May 02 14:04:25 -0500
>they are not in an overly sunny spot, in fact
>if anything its shady, I have lots of pine trees in the yard. They have
>not been cut back and the leaves themselves look very robust. They were
>in big clumps last year and I thought that was the reason for no flowers
>so I have spread them out, but again no flowers. I haven't tried the
>fertilizer but will do that. Do you suggest any particular kind?
Hi Anne,
I wrote a FAQ for the Iris Forum about potential causes of non-bloom in
bearded irises based on things I learned from the folks here on
iris-talk. I'll paste it below so you can see if the suggestions might
help you get your irises blooming. One thing not specifically mentioned
in the FAQ is that some people growing irises in very sandy soil have
found it advantageous to feed considerably higher levels of nitrogen in
their fertilizers because it leaches out of their soil so quickly. High
nitrogen can cause serious problems for bearded irises in loam or clay
soil, but it might benefit them in your sand. Just a thought.
Here's the FAQ:
Here are a few reasons why bearded irises may not bloom:
Not adequately established
Some iris cultivars need a year or more to fully establish
in their new locations
before blooming. If you relocate them frequently, they may
never become well
enough established to bloom. Plant irises far enough apart
to allow for several
years' growth before requiring division.
Inadequate sun
Bearded irises need at least 6 hrs of direct sun a day to
bloom well.
Nutrient deficiencies
Consider having a soil test run to make sure your soil
provides all necessary
plant nutrients in appropriate amounts and fertilize
according to the
recommendations returned with the soil analysis. Soil that
has been growing
irises for many years without amendments or fertilization
is probably
nutritionally depleted. Avoid high-nitrogen fertilizers. If
bearded irises are fed
high-nitrogen fertilizers, they may grow lush foliage with
little or no bloom.
Inappropriate watering
Bearded irises might not bloom well if they experience
periods of extended
drought, though the plants themselves are quite
drought-tolerant. Conversely,
bearded irises that are overwatered are often susceptible
to bacterial soft rot
and fungal leaf spot infections. If you provide
supplemental water, water
deeply no more than once a week. Soaker hoses are
preferable to overhead
watering to avoid spreading leaf diseases from plant to
plant.
Planted too deeply
Bearded iris rhizomes should be planted so the tops of the
rhizomes are at or
slightly below the soil surface. If planted too deeply,
bearded irises will grow
leaves but may not flower. Be careful, also, not to allow
mulch to cover the
rhizomes. Make sure any mulch is pushed away from the
rhizomes.
Overcrowding
Overcrowded clumps often quit blooming until they are
divided, OR irises
closely planted with other plants may not bloom well (or at
all) if they are
struggling to compete for sunlight, water, and soil
nutrients.
Weeds
There are certain weeds and grasses that are so aggressive
they can inhibit the
performance or even survival of plants they invade (Canada
thistle being one
of them). Keep the weeds and grasses away from your irises.
Ill health
Irises that are diseased or under insect attack may not be
able to bloom until
the problem is eliminated.
Late freezes
If a late freeze occurs when flower stalk development has
already started, the
stalk may abort.
Immature rhizome
Rhizomes will not bloom until they are mature. If you have
planted smaller
rzs, you probably need only wait for them to grow a bit
before they'll bloom.
Irregular bloomer
All irises are not created equal. While some irises may
bloom very regularly
in your garden once established, others may never do any
better than
blooming once every several years ... or perhaps never
blooming at all. The
same cultivars that bloom beautifully and reliably for a
neighbor down the
road or a friend across the country may do nothing more
than sulk in your
own garden. The only way to discover which irises will
perform best for you
is to keep trying different cultivars, growing them
properly, and replacing
those that don't meet expectations within 2-3 years after
planting.
Hope that helps,
Laurie
-----------------
laurief@paulbunyan.net
http://www.geocities.com/lfandjg/
zone 3b northern MN - clay soil
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