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Planting and Gardening Guide
About Bearded Iris
Irises prefer a full day of sun,
but will grow and bloom well if given six or more hours of sunlight. The best
time to plant is after the Iris has finished the bloom season and before it
starts new growth. In most cases, this will be between July and October
avoiding periods of temperature extremes. The ideal time is when the summer
heat has ended and cooler fall weather arrives. This will ensure early root
development. The bearded Iris is drought tolerant but will rot if too wet.
Gardeners can avoid many problems by providing good drainage to protect the
Iris from getting "wet feet".
When You Receive Your Iris
When you receive your shipment of
Irises you should remove them immediately to let them air out for about a day
or so before planting them. If you are unable to plant them within a day or two
lay them outside in the shade. Do not put in a closed building where they might
get too hot. Irises can remain out of the ground for a week or two but you
should try to plant within three days of receipt. Water at planting time and
keep moist but not soggy for the first month (see About Sunlight and Water
Prepare Your Soil
A well-prepared bed for your Irises will result in better
growth and bloom. Irises grow in
average garden soils with a PH close to neutral (6.5 to 6.8). They like loose,
well-drained soil since they do not tolerate standing in wet soil. In heavy clay, we recommend raised beds or
raised rows with lots of compost. Some
say that adding coarse sand is good, but you will need to add at least 30% or
you run the risk of creating concrete.
We have had very good results with compost but, as with the sand, it
takes a lot. Irises love compost but not too much green (compost with high
nitrogen content). Although the Iris needs nitrogen, too much in the wet
seasons will promote rotting. You should add compost to your bed, as well as
extra food (fertilizer), to promote the very best growth and bloom of your
Iris. For new planting, well-rotted manure or well-rotted compost is a good
addition. A no-nitrogen chemical fertilizer or super phosphate (or bone meal)
can be dug into the soil at the rate of 1/2 ounce per square foot three weeks
before the plants are set in. If adding
at time of planting, use half strength. It is best to double dig or rototill
your Iris bed to ensure the mixing of the fertilizer and compost before
planting your Irises.
How to Plant Iris Rhizomes
Now that you have your beds ready
in a sunny location, make a shallow hole about twice the size of the rhizome.
Take a handful of the soil you removed and make a mound of soil in the center.
Place the rhizome on top of the mound and drape the roots down the sides of the
mound. Press the rhizome down to ensure that it makes firm contact with the
soil. Any air pockets can collect water and cause rot. When you fill the hole
with soil the top of the rhizome should be at or slightly above the surface for
warm areas and slightly covered for areas with freezing winters. Remember that
it is always better to have the rhizome too high rather that too deep.
In our viewing gardens we plant
the Iris in groups of three, forming a triangle with the toes pointing into the
center. The toe of the Iris is the opposite end of the fan (the Iris leaves).
The spacing we use is 12” apart, with 18" to 24" between each group
of 3 rhizomes. If you prefer to plant in rows, you should space the Iris 18”
apart and all facing the same direction so rhizomes will increase in the same
direction without crowding each other. Be sure to water your Irises well after
planting them. It is a good idea to record the name and location of your
Irises. When they bloom your friends will surely ask for their names.
Mulch before it snows. Use straw
or comparable material, but not with grass clippings as they compact too much
and they promote rotting. Remove the mulch after the last hard frost is
expected in your area to prevent rot from forming when the ground warms up.
About Sunlight and Water
Iris do best in
full sunlight but will do well in slight shade. That is to say, they should
have a good six (6) hours of sunlight a day. In areas of extreme heat and
little water, some shade is good. There are three times when the Iris needs
water. When the Iris is first planted until the roots have taken hold. At this
time the soil should be moist but not waterlogged. You will know when the roots
have taken hold by the new center leaves coming up. This usually takes 2 to 4 weeks.
Once established you should reduce the watering until the winter or autumn
rains set in. During dry spells (over three or four weeks long) you will need
to give them a good deep watering every 3 to 4 weeks depending on the
temperature. The second time the Iris needs water is in the early spring. In
almost all areas, Mother Nature will take care of this for you. In a rare case
that you have no rain or snow and hot temperatures in the spring season, you
should supplement the watering every other week. The third time is for the
reblooming Iris. They will need more water in order to develop stalks and
flowers in the summer and fall seasons.
Irises should be fertilized in
early spring about 6 to 8 weeks before bloom, and again after the blooms are
gone. Because phosphate is important, we recommend using bone meal or
super-phosphate and a light balanced fertilizer such as 10-10-10 or 6-10-10
depending on the amount of nitrogen in your soil. Remember; do not use anything
high in nitrogen as nitrogen promotes rot problems. Have you tested your soil
lately? Soil test kits can be purchased
at most hardware or garden supply stores. What you want to see is neutral PH
(6.5 to 6.8), medium to low nitrogen, high level of phosphorus, and medium level
of potassium. All fertilizers will list the amounts of nitrogen, phosphorus,
and potassium on the container in that order. For example 5-10-15 tells you
that the container has 5% nitrogen, 10% phosphorus, and 15% potassium. Nitrogen
is for the green growth such as grass. Your grass fertilizer is probably 25% or
higher in nitrogen. Do not use it on your Iris! Phosphorous promotes root
development and since the rhizome is all root, it needs lots of phosphorous.
Potassium improves the overall health of the plant, defends against diseases
and helps plants withstand very hot or cold weather. In the autumn it is a good
idea to add bone meal or super-phosphate or both or fertilizer with no nitrogen
such as 0-10-10.
Irises are very hardy plants and
really do not need a lot of attention. Keep your Iris beds weeded and remove
old dried leaves. This will provide air circulation. After blooming, cut the
flower stalks as close to the ground as possible. This will help the Iris to
concentrate its energy in new growth production.
We recommend dividing your Irises
after about 3 to 4 years as they become too crowded. The Iris needs room to
grow new plants. If over crowed, they will be unable to divide and the bloom
will suffer or stop. Over crowding also promotes disease problems from lack of
air circulation. The best time to divide your Irises is about 6-8 weeks after
bloom season, usually in July or August. Clumps can be thinned by removing the
centers of the clumps leaving the newer growth in the ground or by digging the
entire clump and saving the new rhizomes and discarding the old “Mother” plants
or any rhizome that is not healthy or is soft. It is a good idea to keep all
your plants carefully labeled when removing the entire clump. You can use a
waterproof marker to write the name on the leaf of the plant. After digging
your Irises, divide them by cutting the newer rhizomes with fans attached.
Iris the Hardy Plant
Above is the textbook guide to
planting and maintaining your Iris. The truth is, the Iris is a very tolerant
plant. As it turned out we did very
little in following the “correct” way to plant Iris rhizomes. We did not plant
the Iris for over three months and were not sure if they were still alive when
a family member volunteered to plant Iris rhizomes for us. The area we had to
work with is in the foothills and is almost 100% clay soil. We did nothing to
amend the soil, just dug a trench with the garden tractor and put the Iris in
the trench and kicked and pushed the dirt over the Iris. That first summer we only watered once, even
in the months with temperatures in the high 80’s. The point is, the Iris plant
is very tolerant of abuse, is drought resistant, and, by the way, they are deer
If you have any
other questions about your Irises, please feel free to E-mail us, firstname.lastname@example.org,
and we will gladly answer your questions relating to this bearded iris planting
guide and iris gardening guide or any iris planting questions you may have.
you for your order and Happy Gardening!
Chailey Iris Garden
Holford Manor, Holford Manor Lane, North Chailey, Lewes,
Sussex BN8 4DU
Phone: 01444 470157
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