By
Norman Winter MSU
Horticulturist Everyone
ought to consider the Japanese iris, known botanically as
Iris ensata. It complements the Louisiana and Siberian
irises with toughness, beauty and blooms that are born in
glorious summer displays after the other irises have
finished. They flourish from zones 4 to 9. The
Japanese iris produces large blossoms in shades of blue,
pink, white and purple, with bicolored stripes, veins and
blotches. They are available in single-, double- and
peony-flower forms. They are also tall, reaching 24 to 30
inches in height. These are a must for extending your iris
season. The foliage -- bright green with a prominent rib --
is equally attractive. Japanese
irises perform best with at least six hours of sunlight per
day. The soil should be fertile, organic-rich and acidic.
Tightly compacted soils yield an inferior, stunted-looking
plant. If this describes your soil (like it does mine), you
should amend with 3 to 4 inches of organic matter and till
to a depth of 6 to 8 inches. While
tilling, incorporate 3 pounds of a 5-10-5 fertilizer per 100
square feet of planting area. Container-grown
irises that you see in the spring and summer can be set out
at any time during the growing season at the same depth they
are growing in the container. Space the plants 12 to 18
inches apart. In the fall, plant rhizomes just below the
soil surface. Japanese
irises are heavy feeders, so give light applications of a
12-6-6 fertilizer in the early spring and every four to six
weeks throughout the summer. Do not let plants dry out after
fertilizing, as this will quickly burn plant roots. Keep the
soil evenly moist during the growing season. The
best blooming occurs on 2- and 3-year-old clumps. Plants
under good culture require dividing in the spring or fall
every three to four years. Maintain a good layer of mulch
year-round to conserve moisture and to moderate soil
temperatures. The
Japanese iris complements a water garden, pond or creek and
actually can be grown in water. However, they do just as
well in fertile upland soils. Plant the Japanese iris boldly
in informal drifts. Some of the prettiest displays are with
other Japanese irises placed in groups of different colors.
The large leaves look striking in the tropical garden when
combined with elephant ears, ferns and bananas, and in front
of larger ornamental grasses. There
are more Japanese iris varieties than you ever dreamed.
Garden centers stock more every year, and Mississippi
specialty growers have a good selection. Favorites are Cry
of Rejoice (purple with yellow center), Diomedes (blue),
Rikki-Pikki (white), Loyalty (violet-blue, double blossoms
and yellow striping on the falls) and Sapphire Star (pale
lavender with white veins). Spring
is hitting the Coast and is within sight of the
Mississippi-Tennessee border. All gardeners within those
boundaries can grow the Japanese iris. I doubt there will be
a single complaint from anyone who gives them a
try. Released:
March 10, 2003 Editor's
Note: Ideal publication dates of Southern Gardening columns
are within one month of their release. Editors should
examine older columns carefully for any information that
could be time sensitive.
Southern
Gardening
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Japanese irises
yield spring, summer color
Central Mississippi Research & Extension
Center
The
past few years have given me a new appreciation for the
various iris species available to Southern gardeners. With
careful selection, we can enjoy a long season of iris
blooms.
Contact: Norman
Winter,
(601) 857-2284
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