There are two basic kinds of Iris;
Bearded and plain. There are also
miniatures that grow only eight inches
tall as compared to the traditional Iris
which grows up to about three feet tall.
The Iris is a perennial plant that grows
from a root called a rhizome. Plant them
about 12 inches apart. The rhizome
should be planted even with the soil
with the top of the rhizome above
ground.
Plant Irises in full sun or partial
shade. Iris needs well drained soil.
Root rot can result if they are planted
in soil that stays too wet. They
tolerate drought very well, needing
water only during the driest part of the
summer. Fertilize lightly about 6 weeks
before bloom time.
Plant in July or August. The
plants need to be well established to
get through the winter.
Mulching is a matter of preference. A
little mulch will help keep down weeds
but the rhizomes need sunshine so do not
mulch very deeply.
Divide Iris every 3 to 4 years or
whenever they stop producing as many
blooms. That is a signal that they need
more space. Dig up and plant only the
newest part of the rhizome tossing the
older parts into the compost pile. When
transplanting be sure each rhizome has
some root and at least a couple of
leaves.
Irises aren't bothered by many insects.
The root borer is the major pest of
iris. It is a caterpillar that chews on
the rhizomes and causes the rhizome to
rot. Thrips can cause damage to the buds
but can be easily controlled by spraying
insecticidal soap or by dusting the buds
with diatomaceous earth.
At the end of blooming time the stems
should be cut off but the leaves should
be left to grow the rest of the summer.
The leaves are making food for the
rhizome so the plant can flower again
next season. Any leaves that have brown
spots or look unhealthy should be
removed.
