- with tips on planting and care, including how to divide irises
by Marilyn Pokorney
The beautiful Iris is a very easy plant to grow.
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, August, or September. For southern states
October and November are not too late. 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.
About the Author: Marilyn Pokorney is a freelance writer of science, nature, animals and the environment. She also loves crafts, gardening, and reading. Website: AplusWriting.net
Divide bearded iris every three to five years. Do it from midsummer until the end of August in order to maintain vigorous clumps, reduce crowding, and remove rhizomes infested with iris borers.
The rhizome is a thickened underground stem. It stores food produced by the leaves. Fibrous roots grow from it in the spring until after flowering, and again in the fall during moist cool weather. During midsummer, few new roots grow, so you can dig up, divide and transplant iris. Finish the job before October so plants can anchor themselves well before winter.
Iris must have full sun and well-drained soil. To divide iris, dig up the old clump, wash the soil from the rhizomes, and examine them. Cut off any parts of the rhizomes that are rotting or have iris borer holes. Put these rhizomes and any diseased leaves in the trash rather than adding them to your compost pile. Cut the healthy rhizomes into sections. Each division must have a fan of leaves, several inches of rhizomes and healthy roots. You can also make a larger division with two fans of leaves and a V-shaped portion of rhizomes. Cut the leaves back to one third their full height.
Dig a shallow hole in your selected sunny site. Make a cone of soil in the center and place the rhizome on it with the roots spread outward. Fill in the soil, just barely covering the rhizome with soil. Water well.
Space iris divisions about 18 inches apart. You can plant divisions of the same variety in a triangle with the fans facing outward. This gives a good color display the first blooming season.
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.
