One would not dream of a well-planned late spring garden without at least a few varieties of iris standing among the aquilegia and peonies.
But what was the picture a few weeks earlier? Perhaps a small group of daffodils looked out over the expanse of foliage from later blooming plants, or maybe a smattering of tulips were dotted irrelevant here and there.
Or perhaps, like so many gardens that lack suitable soil or location for a spring bulb display, there was no bloom at all!
Dwarf Irises In My Perennial Garden
A few years ago, my perennial garden was in this desolate condition in early May. Then I started planting some dwarf irises. That clump of daffodils looks at home in the impressive purple and gold ribbon that runs the full length of the border.
Tulips took a new lease on life when intermediate irises were used to enhance their beauty. My favorite combination is a group of pale pink tulips with the deep wine ‘Red Orchid.’
Hybridized Iris Pumila
In recent years, the tiny species Iris pumila has been hybridized with tall bearded types giving us irises ranging in height from 4” to 24” inches over a color range almost as large as the tall bearded irises.
Although miniature, the dwarfs carry blooms remarkably similar in form to their larger relatives.
The narrow spear-like foliage of the dwarf irises can also play an important part in foreground planting after the bloom. Single divisions planted six inches apart will form a solid border by the following summer.
Or they can be spaced unevenly to break up the monotonous flow of an annual border, such as alyssum or dwarf marigolds.
Dividing Is Necessary
Dwarf irises seem to propagate more profusely than the taller varieties (at least that has been my experience); therefore, the clumps’ division should be made every 2 or 3 years.
‘Tampa,’ a red miniature 6″ inches, propagates so abundantly that a single rhizome will produce at least 20 divisions by spring.
Digging and dividing can be done any time after blooming, provided enough time remains in late summer so the clumps can establish themselves before the ground freezes.
Suppose there are many clumps of tall bearded irises and dwarfs and intermediates to divide. In that case, this job can be spread over a long period by starting on the dwarfs after they have finished blooming and ending with late tall bearded irises.
Although a clump should be divided into single shoots, divisions consisting of three or four rhizomes will display a larger bloom display. Single divisions planted 8″ to 12″ inches apart in a triangle are also effective for a mass of color.
Dwarf Rhizomes
Dwarf rhizomes resemble the larger types except in size. Use only the rhizomes from around the outside, the top of this mound, and place the rhizome on this with the roots spread out around it. Then fill the soil in over the roots and rhizome.
Care After Planting
Little care is needed after planting Iris. However, a good soaking twice a week is needed if a hot, dry spell follows the planting.
Hand-pulling of weeds is necessary. No matter how careful one is with a hoe or even a small hand rake, the rhizomes can easily be pulled out by catching it or a root with the tool.
A light peat moss mulch is beneficial when applied over a new planting. It will conserve moisture and help prevent a hard soil crust from forming.
Unless planting has been done very early in the summer, some winter protection should be given the first year.
A light mulch of straw, cornstalks, or evergreen twigs applied after the ground is frozen will prevent the small rhizomes from heaving.
Be sure to remove the covering early in the spring for dwarf irises that seem to know when to start growing, and any growth made under such coverage will be more susceptible to light freezing.
Dwarf irises combined with several other early blooming perennials can be very pleasing to the eye virtually days after the last freezing blast of winter.
Low-Creeping Subulata
Subulata, the low creeping form of phlox, offers innumerable opportunities for use with dwarf irises.
Plants of the tiny reddish-purple ‘Tony’ placed through a solid cover of pink creeping phlox can truly enhance the beauty of a slope or rock garden.
One group of plants that must always neighbor each other in my garden are pale yellow daffodils bordered by lavender phlox and deep purple dwarf irises.
The bright yellow of perennial alyssum, when interplanted with a few divisions of the purple dwarf ‘Marocain,’ can give your garden an eye-catching border already the last week in April.
Versatile Intermediates
Intermediate irises are just what their name implies— intermediate in height, taller than the dwarfs but shorter than the tall bearded. And they are intermediate in their blooming season, starting after the dwarfs have finished but a week or two before the tall bearded varieties come into bloom.
For these reasons, no iris planting should be made without at least a few intermediates. They are a little difficult to find, but many iris growers have lists with approximately 30 varieties from which to choose.
Many of these irises will reward the gardener with another display of bloom in the fall. Irises coming into bloom with the mums and dwarf hardy asters certainly can become subjects of widespread conversation.
If clumps are given good care through the summer with an emphasis on watering and frequent division, there is no reason why the fall show cannot be as great as the one in spring.
Reliable Fall-Blooming Varieties
Wide reliable fall-blooming varieties are distinguished by the word ‘autumn’ in their names.
A few that have never let me down in the fall are: ‘Eleanor Roosevelt,’ an almost black purple; ‘Southland,’ deep yellow; and the white ‘Autumn Queen,’ which I have had bloom from May through September.
44659 by Pat Shedesky