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IRISES

Aril and Aril Bred Iris

Aril and Arilbred irises are derived from native species of the Middle East. They have some of the most remarkable color patterns.

The pure arils go completely dormant in the summer, which make them susceptible to rot in rainy or humid climates. The arilbred are much more adaptable - preferring hot, dry summers.

Where to Plant: Aril and arilbreds are more difficult to grow in parts of Canada where the summers are moist. They are more easily grown in warm, dry regions of the country, especially in desert-like areas such as Alberta and Saskatchewan. Raised beds or sloped beds may be advantageous provided these offer good drainage. Select an area with plenty of sunshine and good drainage. In the desert and high altitude areas where the sunshine is intense, afternoon shade is suggested.

Soil Preparation: Good Drainage is essential to growing arils and arilbred iris. If the soil is acid or neutral, add limestone to increase the pH. Arils and arilbreds prefer a more alkaline soil than do bearded iris. The alkaline soil needs to contain a good amount of calcium and magnesium, which can be obtained by using slaked lime or ground limestone. Dolomitic limestone, which contains magnesium, is especially good. The soil must be highly fertile and rich in mineral nutrients. Organic matter, such as well-prepared compost, is beneficial.

Distance Apart: Giving them more space for circulation is suggested. These iris resent crowding.
Watering: If summers tend to be dry in your region, stop watering and allow the plants to go dormant during the hot dry months. Begin withholding water right after the blooming season. If summers are excessively wet, arils can be protected from excessive water using overhead awnings or canopies. The key to growing is providing good drainage.

Fertilizing: Arilbreds are heavy feeders and benefit from regular fertilizing. Feeding with soluble fertilizer having high potash and phosphate rating may be useful.

Bloom Season: Arilbred iris bloom with the Standard Dwarf and Intermediate Bearded iris.

Moving & Thinning: Many of the arils and arilbreds increase rapidly and require dividing annually or every other year to avoid overcrowding. Again, thin and replant when summer days begin to cool and before winter days begin.
Pests & Diseases: Arils and arilbreds are subject to the same array of diseases and pests as Tall Bearded Iris – including attacks by aphids, whitefly, iris borers and other insects, and by leaf spot, rhizome rot and other fungi, bacteria and virus.

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Beardless Iris

Can be used in moist soils and near water. They grow in full sun, but prefer partial shade and are best planted in late summer or early fall.

Soil moisture is important in the spring when the plants are growing.

Planting: Plant root divisions in the early spring or just after blooming. Early fall planting is successful in all but the most northern sections of the country. Divide clumps (as shown in diagram) and plant single rhizomes, spacing them 8 to 18 inches apart according to effect desired. Spade planting hole about 10 inches deep and work 1 tablespoonful of fertilizer into the soil in the bottom of the hole. If the soil is heavy, some drainage material such as gravel or broken pottery should be placed in the hole. Fill the hole with the loose soil and place the root section so that it will not be covered more than 1 inch deep. Most Beardless Irises can also be propagated from seeds.

Feeding: Iris growers have learned that early theories about plant foods being dangerous to the growth of iris are unfounded. However, they will not tolerate fresh manure or even partly rotted manure in direct contact with the roots. Fertilizer provides all the plant food irises need from the soil for the best growth and beauty. Fertilizer should be scratched into the soil around the plant early each spring at the rate of I tablespoonful per plant (1 pint per 25 square feet of area).

Dividing: Most irises should be divided every three to five years. Divide when the root clump becomes crowded and the stems become numerous thin and weak.

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Bulb Irises

These are the kind you generally see in florists shops. The other kinds grow from rhizomes (creeping underground stems), but these grow from a bulb, like tulips do.

Their foliage disappear every summer.

They can be very effective when used in annual or perennial flower beds, lending and extra splash of color and then fading away until the next year. All bulb iris benefit from a dose of slow release bulb food when being planted, and then also again in the spring or summer as they are blooming. Fertilizing helps build strong healthy plants and promotes more increases of the bulb. Once planted, the bulbs generally do not need to be lifted or divided for a number of years.

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Bearded Iris

Planting: Unlike most spring bulbs, bearded iris don't require a period of cold to produce blossoms, making them perfect for areas with mild winters. They are also extremely drought tolerant, good for areas with little or no summer rains. Bearded irises are not actually bulbs, but rhizomes, a kind of thick brown root. Hardy in zones 3-9, the rhizomes need plenty of sun to bloom well and regularly. They do best in well drained soil, but will tolerate less drainage in drier areas.

To plant a rhizome, dig a large hole, fill the center with a mound of well broken up soil and set it on top. If planting in the fall when dormant, cut back existing roots to about three inches. Iris planted in the spring should have their roots fanned out around the sides of the mound. The rhizome itself should sit at about ground level. Growers differ as to whether it is best to cover the rhizome completely with a light layer of soil or to leave the tops a bit exposed.

Feeding: Cut off dead blossoms and dead bloom stalks when the iris has stopped blossoming, but don't cut back the leaves until they begin to turn brown in the fall. The leaves are needed to produce next year's blooms. When you do cut, leave a fan shape about six inches long. Feed your irises a teaspoon of bone meal every fall and when you replant. You can feed again a month before they usually bloom if you like, but they are quite tolerant of just one feeding.

Dividing: When the rhizomes become hunched and crowded – usually after 3 or 4 years – divide the rhizome by gently lifting them from the ground and dividing them into sections, making sure each section has feeder roots and a fan of leaves.

The range of iris height and bloom size is amazing. The height of the standard bearded iris ranges from 3 inches to 40 inches with blooms 11/2 to 8 inches across. Colors range from snowy white to any conceivable color and shade, including yellow, orange, pink, red, lavender, purple, brown, to almost black. Often, the standard and the fall of the iris will be different colors.

Some Great Iris Resources

• American Iris Society
• Bearded Irises
• Canadian Iris Society
• Home Page For Irises
• Miniature Irises

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