Last fall, I planted rhizomes of tall bearded iris (eight varieties). I
planted the rhizomes shallowly, with the tops just under the surface of the
soil. This spring, DH and I mulched the entire garden, about 2" deep, using
a locally-made composted bark mulch. Since the rhizomes were at the same
level as the rest of the soil, they got covered. I'm sure that this was a
mistake.

Some of the irises bloomed. Others look poor. I fertilized, in early spring,
with a sprinkling of 20-20-20. Last week, I fertilized, with a slurry of
superphosphate and dissolved potassium chloride.

Yesterday, I dug down to the level of the rhizomes, uncovering the tops to
the sun (as advised by several iris mavens). Although most of the rhizomes
looked OK, one had a mushy section.

My town has damp winters and dry summers. Total annual rainfall is only 15"
or so. The temperature seldom rises above 70°F in summer (it's been about
62°F or so, for the past few weeks). The winters are mild (temperature
seldom drops below 25°F, usually in the low 40s during the day).

Questions:
1. Should I lift the plants now, to reset them at ground level? Or should I
leave them in their dug-down "pits" until later in the year? Between soil
subsidence and the mulch layer, the holes to the rhizomes are 3" deep. When
should I dig them? Should I dig out the mushy rhizome now, or leave it till
later?

2. Should I plant them above the ground level, for drainage? Due to the low
rainfall, drought-tolerant plants are more used, in this area. I'm afraid
that raising the irises will make them more vulnerable to drought.

3. The weakest plant, which has just a tiny leaf that is practically dead,
has a healthy-looking rhizome (only 2" across, but firm). Now that it is
uncovered, it appears to be making new, little fans from a couple of eyes on
the surface. Is this normal? Should I leave this one in place, even if I
move the others?

Any further advice?

Wendy
Sequim, WA (Zone 8)

Questions:
1. Should I lift the plants now, to reset them at ground level? Or should
I leave them in their dug-down "pits" until later in the year? Between
soil subsidence and the mulch layer, the holes to the rhizomes are 3"
deep. When should I dig them? Should I dig out the mushy rhizome now, or
leave it till later?

As long as you wait until after they bloom, it should be safe to move them.
I just moved some of my bearded irises to a new spot. I have done this
before without any harm. Usually the first year after that, the irises don't
do well but after that, they do wonderful.

2. Should I plant them above the ground level, for drainage? Due to the
low rainfall, drought-tolerant plants are more used, in this area. I'm
afraid that raising the irises will make them more vulnerable to drought.

I make sure the rhizomes are just barely under the soil. We have had drought
conditions here in SC and the irises still do well. They are pretty hardy
here.

3. The weakest plant, which has just a tiny leaf that is practically dead,
has a healthy-looking rhizome (only 2" across, but firm). Now that it is
uncovered, it appears to be making new, little fans from a couple of eyes
on the surface. Is this normal? Should I leave this one in place, even if
I move the others?

I have had lots of little babies show up and that is normal. You can even
move the babies when you move the others.


Good luck!

loonyhiker
South Carolina zone 7

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