Blue flag attracts bees and hummingbirds. The roots and rhizomes of irises are extremely poisonous to humans and animals. Native American tribes used irises medicinally. Some tribes also used the outermost fibers of the leaves to create twine.

And they don’t all come with warning names like “deadly nightshade.” Irises, calla lilies, sweet peas and potato flowers are all lovely to look at, common decor at weddings or in the garden (or at garden weddings), and completely dangerous if ingested.

The rhizome of the Blue Flag is poisonous, but was used by colonists, with guidance from Indian people, for various healing purposes.

Some insects feed on Blue Flag Iris and other Iris spp. Caterpillars of such moths as Ctenucha virginica (Virginia Ctenucha), Spilosoma congrua (Agreeable Tiger Moth), and Macronoctua onusta (Iris Borer Moth), also feed on these plants.

Verify that the rhizomes are firm and have not begun to shrivel. If stored improperly, iris rhizomes shrivel and dry, and they may not bloom reliably.

Birds that eat irises certainly have good taste. They can’t be faulted on that one. Fortunately for the birds I have an organic garden so I don’t use poisons.

Insects. Crickets, aphids, moths and moth larvae known as the iris borer are all predators of the iris plant.

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How to identify iris borers. The pinkish caterpillars are two inches long when full grown. Adult moths have chocolate-brown front wings and lighter yellow-brown hind wings with a wing span up to 2 inches.

Spinosad

Iris borers can be controlled by sanitation and the timely application of insecticides. Remove and destroy dead iris foliage in late fall or early spring. This will eliminate many of the iris borer eggs. An insecticide should be applied in spring when the new shoots are 4 to 6 inches tall.

Revitalizing your Irises involves digging them up, removing the dead or diseased rhizomes and then replanting them. You’ll need a shovel and a sharp knife to properly perform these tasks. Step 1 – Carefully dig up the iris clump to avoid damaging the rhizomes and then separate the rhizomes from one another.

5 to 20 years

To avoid rhizome rot, be sure to plant your Bearded Iris in an area with good drainage. If you don’t have any beds with good drainage, consider building a raised bed or adding peat moss to your soil. Overcrowding can also cause rhizome rot so make sure to start your Bearded iris out with plenty of room to grow.

Siberian irises grow well in cool, wet conditions and, though they thrive in full sun, they can also tolerate some shade.

Choosing and Preparing a Planting Site

• Irises will bloom best in full sun.
• Bearded irises must not be shaded out by other plants; many do best in a special bed on their own.
• They prefer fertile, neutral to slightly acidic soil.

Crowded irises often refuse to bloom. Pests: Disease or pests can stress plants and reduce or eliminate blooming. Planting depth: The rhizomes should be planted so that the top surface is at or slightly below the soil. Irises planted too deeply will produce leaves but no flowers.

Is Epsom salt good for Iris? Yes, there seem to be good, relevant reasons for using Epsom salts for plants. Epsom salt helps improve flower blooming and enhances a plant’s green color. It can even help plants grow bushier.

‘The traditional system of autumn thinning every three to four years allows irises to become overcrowded, leading to shading,’ explains Antony. ‘It also disturbs the plants at the very moment they are trying to set flower initials, resulting in an unreliable show of flowers the following year.

A number of bearded varieties bloom from early spring to early summer. Among beardless irises, many varieties in the Spuria subgroup bloom from late spring to midsummer. Some Siberian iris (Iris sibirica) and Japanese iris (I. ensata) selections bloom from mid-spring to early summer.

Ideal iris soil pH is 6.8 and soil should have average levels of nitrogen, but sufficient amounts of phosphorus too, the nutrient that helps plants form flowers. An amendment of superphosphate, colloidal phosphate, or bone meal applied in early spring can help plants develop blooms.

Reblooming Types “Rebloomers” (also called “remontants”) are irises that produce two or more flushes of bloom each year. “Cycle rebloomers” produce a spring crop of flowers, then lie low during summer, and grow and flower again in the fall.

Whereas many gardeners do little with once-blooming irises other than weed the bed periodically and divide them every few to several years, rebloomers could use a little extra help. Feed after the first bloom and again in summer, using a low-nitrogen fertilizer. Cut the old stalks as soon as flowering has completed.

Irises multiply fairly quickly and when the plants become overcrowded they produce fewer of their lovely blooms. It is very easy to divide iris plants to rejuvenate them, and for the best display, bearded irises should be divided every three to four years.

A: After your irises have bloomed, you can indeed cut down the flower stalk; this process is known as “deadheading”. However, you should not cut down or tie up the irises’ leaves at this point, even if they are a bit unsightly.

Divide at the right time of year, after flowering, when irises become dormant during late summer, reducing the chance of bacterial soft rot. Avoid dividing during winter when irises are trying to survive on stored energy in their rhizomes. Snip the leaf blades to about one third of their height.