Growing Bearded Iris
Growing Conditions
Full sun.
There's little point trying to grow these in shade or part shade conditions as the blooms reduce in number with shade.
Morning shade seems to work out better than afternoon shade if you have to make a choice.
Excellent drainage.
Clay soils and their water holding capacity will rot the tubers out.
Decent fertility.
This plant survives in darn near any soil (other than clay) and if you toss a shovel of compost on it in the spring, it will bloom its heart out. Don't overfertilize or you'll create soft, lush growth that flops easily.
Planting.
The number one problem with planting bearded iris is that gardeners plant them too deeply. The main tuber should be laid on the surface and the roots coming off it should be buried in the soil. If you cover this main tuber, you're going to find the plant grows great leaves but doesn't flower.
No Flowering
If you have a plant that doesn't flower and you can't see the tuber, dig it up and replant properly.
Propagation
Bearded iris grow easily from seed although named hybrids will not come true.
You may find yourself with a wonderful new color!
Treat them as any other perennial and see the propagation articles for directions. T
hey also are quite easy to divide. Divide 4-6 weeks after blooming and replant immediately.
Hardiness
If drainage is right, this plant lives to USDA zone 3.
Iris Borer
The major problem faced by gardeners is the iris borer.
This pest bores holes in the leaves (you'll see brown pin pricks and streaking) and the new larva burrows its way to the tuber where it eats and grows big and fat.
Tunneling through the tuber leaves big holes in there, weakens the tuber and allows rotting to become established.
Preventing this problem in an organic garden simply means digging the tubers every 2 years, dividing them to remove any infected areas (burn them or destroy them - do not compost them) and watching tubers closely for any sign of damage.
Dig and clean up at the first sign (usually 4-6 weeks after blooming)
You can dust the leaves with rotenone in an attempt to kill off the adult female as she lays her eggs but the timing has to be perfect on this (rotenone only last 24 hours in the sunlight before it degrades).
Cleanliness is the best option here along with constant vigilance.
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