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Iris: The Rainbow Flower

Irises come in every color of the rainbow.  They are versatile plants, having a wide range of uses in the garden.  There is an iris for almost every garden need:  wet or dry, short or tall, spring or fall flowers, as specimen plantings or groupings.  You can have irises in bloom from March through November (and sometimes December) even in zone 6.

 

There are two main categories of iris:  Beardless and Bearded.  Within the beardless irises several types including those below.  These each have their own cultivation needs, which you can learn more about at Draycott Gardens.

  • Japanese which love water, bloom in July, and have beautiful color patterns
  • Siberian are very graceful with leaves that stay green and lovely throughout the growing season. They bloom in June
  • Louisiana which need lots of water and were the first group of irises to achieve true red color
  • Dutch irises are the only ones that grow from bulbs, and are often used in floral arrangements
  • Flags while pretty are invasively vigorous and can quickly choke waterways
  • Pacific Coast Natives are some of the loveliest irises with beautiful flowers and color patterns but they only grow well in specific areas – hence the name

 Bearded irises are what most people think of when you say you grow iris.  They come in a wide variety of sizes and bloom seasons.  Learn about bearded irises at Iris Hills Farm.

  • Minature Dwarf Bearded Iris bloom in early April and are the smallest bearded irises at less than 8 inches tall
  • Standard Dwarf Bearded Iris range from 8-15 inches and bloom in mid-April to very early May. They are cute and vigorous, filling the garden with color when very little but tulips and daffodils are yet in bloom

There are three types of bearded iris that all grow between 16-27 inches tall:

  • Intermediate Bearded are robust and lovely, blooming in between the dwarf and taller irises
  • Miniature Tall Bearded are graceful with stalks and flowers that are slender and petite, often walking away with awards at iris shows
  • Border Bearded have the same size flowers as the Tall Bearded irises but have shorter stalks
  • Tall Bearded Iris are big, showy, and colorful, growing up to 4 feet tall

 

The most prevalent irises in home gardens are the Tall Bearded Iris.  They originally had droopy falls, a fragile texture, and much smaller flowers.  They only came in purple, white, and yellow.  Due to the vast amount of hybridizing in the iris world since 1930 they now can be found in every color of the rainbow.  The falls have become more and more ruffled while the flowers are bigger, often sporting lacy edges or diamond-like dusting.  The texture of the flowers is more substantial, and the beards have become quite wild, even sporting strange looking appendages called spoons and flounces.

 

One of the loveliest advances in bearded iris hybridizing has been rebloom and ever-blooming varieties.  These are flowers that bloom in May, then again in the late summer or fall.  A few even bloom over and over May through November if they receive enough water and fertilizer.  Yet the reblooming varieties are the only ones you need to worry about watering.  In general, bearded irises are very drought tolerant, and have the distinct advantage of being deer resistant.

 Bearded iris can be planted anytime from July-September.  When deciding where to plant bearded iris, remember that the more sun they get, the more they bloom!  They prefer slightly alkaline soil (ph of 7 or more), and need excellent drainage.  Dig a hole deep enough to plant the roots straight down into the hole.  Gently pack in soil, slightly covering the top of the rhizome and firm down.  Rhizomes (this is the nutrient storage package of the iris, similar to bulbs or tubers) need air and sunlight.  Water at planting, and again a few days later.  Then water weekly the first year until summer droughts are over.  After that, let God do the watering as they will withstand weeks of drought by their second year.  Always water in the morning or evening to avoid rot.

 For the lowdown on caring for your bearded irises see Taking Care of Your Irises at Iris Hills Farm.  You should follow the following annual schedule:

  • Clean up dead leaves in early spring and look for tiny bite marks on the leaves which signal borer infestation. If you need to control borers either hand kill or use an insecticide containing imidacloprid.
  • In summer, cut stalks down to the ground (leave the leaves as they are) to keep out rot. Divide any clumps that are more than 5 years old.  If leaf spot (brown spots) are occurring heavily on the leaves you can spray with a fungicide.
  • Clean up the leaves again in the fall and insulate from the cold with a 1/2 inch covering of leaf mold.

Irises are easy to grow, lovely to look at both in the garden and in a vase, and come in intriguing scents and colors.  Plant your own garden rainbow this year and fall in love with irises!

Photos by (top to bottom): Display Gardens at Iris Hills Farm; ‘My Missus Carter’ by Colin Campbell; ‘Debra’s Melody’ by Colin Campbell

Published on Apr 30, 2020

Mother Earth Gardener

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