By Chad Harris
Iris ensata
and laevigata have been cultivated with container culture for centuries. In
Japan several different flower forms and indoor display regulations were
specifically formatted for container growing of Iris ensata. You may also find
that growing these water lovers and the new hybrid “Pseudata” in containers
easier, as you will have better control of the rich moist soils that they
demand.
Soils: A
good soilless container potting medium should be used. Here at Mt. Pleasant Iris
Farm we use ‘Miracle-Grow’ with 6 month feeding. We use it not only for the patio
container, but also for the germination of the seed of our breeding lines.
Container: A
one gallon container is the minimum, for a single or double fan plant. This
will keep the plant for one growing season, requiring yearly transplanting.
One gallon containers need to be transplanted yearly for the health of your plant and container.
I highly recommend that a larger container be used;
three to five gallon will be optimum for two to three year growing seasons. Note
that the size of containers for starting seed is a one half gallon.
Seedlings in half gallon containers.
The seedlings are grown for one to two years
in this size before being transplanted out to the field.
Light: Full
sun with a minimum of six hours to bloom properly. Areas with more intense sun
and or heat will find that morning sun and afternoon shade will benefit both
the plant and the bloom. While the plant wants to be in the sun the root zone
needs to be kept cool. With a large collection this can be achieved placing the
containers close to each other while shading the outside containers with planks
boxing them in. The smaller collection the shading can be achieved by double
potting.
Shading the poly container by double potting.
Placing the
smaller container into a larger heavier decorative ceramic container, this is
the method that we use on our patio. One could also use a very large decorative
container that could hold several smaller poly or plastic containers. A clump look
with many different varieties can be achieved without mixing them up, losing
their names.
Iris ensata in containers.
Water: These
plants are water lovers and should not dry out, keep evenly moist. During the
summer this may demand a daily watering. A deep tray filled with water will
allow the plant to stay completely hydrated for longer periods of time. For
larger collections a child’s wading pool could be used, or a box made of planks
lined with a pool liner. Drill holes into the sides one to two inches from the
bottom for overflow drainage. The rhizome of the plant should be above the
waterline, this is critical for Iris ensata especially during the winter months.
Iris laevigata can grow with its crown under water with two inches covering;
however it is best to start the new plant above the waterline to help prevent
rot. You can gradually submerge the plant after new growth appears. Pseudata (being
half Iris ensata) I would play it safe and would grow as Iris ensata, with the
rhizome above the waterline.
Iris ensata in containers.
Fertilizer:
Use a slow release for acid loving plants mixed into the potting mix. Or use a
water-soluble and add directly to the water. Do not use Bone Meal in any
application as this will change the PH and can kill these acidic loving plants.
Iris laevigata in patio containers.
Transplanting:
Repot right after bloom, discarding the old soil, roots, and rhizome. The new
rhizomes are in a full growth mode at this time through the summer and fall until
the winter sets in.
First frost: time to cut the foliage back.
Winter Care:
After a light freeze, cut all of the foliage off at container level. Mild
winter areas (USDA Zone 8-9) containers can remain out in the pools and or
above ground. Colder climates the containers should be lifted from the flooding
pools or trays and buried in a prepared bed with a good mulch cover. In the
spring return the containers to the flooding pool, lightly fertilize after new
growth starts to appear.
For the many
that have tried to grow these water lovers in their garden and have failed,
give container growing a try. It is definitely easier to maintain their
demanding cultural needs of a rich moist soil. You may also be able to push the
envelope of where they have not been grown before surprising your iris club at
your next show. Give one a try.
