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Elisabeth C. Miller Library

Keyword: Iris

Dwarf and Median Bearded Irises: Jewels of the Iris World

Kevin Vaughn is an active grower and breeder of iris in Oregon.  His newest book, “Dwarf and Median Bearded Iris” focuses on the development of varieties smaller than the more familiar tall bearded selections.  These are very useful garden plants, as they do not dominate their setting or requiring the staking often needed by their taller cousins.  The history of their development may be of interest only to the most devoted iris fan (yes, I’m guilty as charged), but the author balances this with innovative planting designs and good suggestions for companion plants.  He also names his favorite varieties and many are available from one of the several iris gardens in our region.

Long-time Arboretum Foundation members will remember Jean Witt (1921-2016), who was the widow of Joe Witt after whom the Winter Garden is named.  Jean was also well known as an iris breeder, and especially of the medium size varieties.  Until reading this book, I didn’t realize how instrumental she was in the creation of these classes that were only recognized and defined in the mid-20th century.  New varieties from her breeding have continued to be introduced on her behalf up until the last few years.  One of my favorites is ‘Little White Tiger’ from 2009.

 

Excerpted from Brian Thompson’s article in the Spring 2023 issue of the Arboretum Bulletin

Siberian iris care in winter

Do I leave my Siberian iris alone through the winter, then cut them back in the spring when new growth starts to show, as I’ve done in the past, or do I cut them back now? My neighbor has had hers cut back for months now and insists her way is best…

 

According to the book The Siberian Iris, by Currier McEwen, 1996, you should
“allow leaves to remain on the plants as long as they are green and adding energy to the plant through photosynthesis. When they turn brown in the fall, cut them off as low as possible and burn them.* It is risky to add them to the compost pile, as they may carry fungal spores, insect eggs, and other disease agents.

*Or put them in your trash (in a sealed bag).

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Dividing and transplanting iris

When is the best time to divide and transplant Irises? I have Japanese, bearded and yellow flag (I think) irises.

Rhizomatous irises (the kinds you have) are best divided in midsummer:

Lift rhizomatous kinds, such as bearded iris, in midsummer and cut rhizomes into sections, each with roots and a fan of leaves; replant, with tops barely covered, 6 inches apart. Flowers will be sparse the next year, but good thereafter.
(Source: American Horticultural Society Plant Propagation, ed. by A. Toogood, 1999, p. 202)

“The optimum time..is six weeks after flowering. This is usually in midsummer, allowing time for the new rhizome to become established and make sufficient growth to produce fans to flower the following year. New roots that began growing immediately after flowering will then be strong enough to help anchor the new plants. Early spring is another suitable time, just as the other main period of root growth is about to start, but flowering may be forfeited, and if flowers are produced the stems will almost certainly need staking. Bearded iris cultivars are tough, and if the rhizome is large they can survive out of soil for many weeks. This is not an ideal situation, but it makes transport of the plants easy.”
(Source: The Gardener’s Guide to Growing Irises, by G. Stebbings, 1997, p. 93)

Good instructions can be found in these articles:
Digging, Dividing, and Replanting Bearded Irises
Garden Experiences: Dividing Bearded Iris

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Mulching around irises

I covered my iris bed with wood chips to keep the ground from drying out so fast. Since the rhizomes grow partly above ground, will being covered with chips harm the plants?

Your mulch is unlikely to harm your bearded (rhizomatous) irises, as long as it is less than one inch thick over the rhizome tops and allows air through. Here is some information from The Gardener’s Iris Book by William Shear: “How deep should the rhizome be set? That depends. In light-textured soils, it can be covered by as much as one inch of soil, but for average to heavier soils, the top of the rhizome is best left exposed to the healthful influences of sun and air. Remember that the rhizome is a stem, not a root, and needs to breathe!…If you do apply a mulch, it must be loose and airy, so it won’t pack down and get soggy–a sure ticket to rotting rhizomes in the spring.” Shear suggests pulling back the mulch in spring (since it is for freeze protection in his mind), but it seems to me that would defeat your purpose. You might meet both goals (moist soil and dry rhizome tops) by mulching around the irises but not right on them.

on Iris sibirica ‘Mantra’ and its cultural requirements

I am looking for information on a Iris sibirica ‘Mantra.’ I want to know what it looks like, what its cultural requirements are etc. If you can find an image, that would be awesome.

 

The iris you mention is actually not a Siberian iris. Here is a photo from the Miller Garden website’s alpine collection which lists this as a Pacific Coast iris, rather than Iris sibirica.
This iris won an award of merit from the Pacific Coast Iris Society in 2000. Here is general cultural information from the King County Iris Society.

Pacific Coast Native Iris (PCN), or Californicae (CA), are much sought after in the Pacific Northwest as our climatic conditions are ideal for them. Their graceful and dainty flowers bloom April to June on stems 1′ to 2′ tall, in a wide variety of striking colors and patterns. These irises thrive in the marine coastal climate, with dry summers and cool, wet winters. Plants are very prolific and grow readily from seed. Transplanting, however, can be difficult. They are best moved or divided in the early fall, when root growth is active and can continue well into winter. Plants can also be moved prior to spring bloom.

Transplants must be kept well-watered until natural rainfall can maintain high soil moisture. They should be heavily mulched with bark dust, pine needles or leaves, to prevent frost damage to newly developing roots. Once established, plants are usually tolerant of normal freezes and periods of drought. If frost damage occurs to leaves, wait until well into spring to watch for signs of new growth. PCNs should receive at least a half a day of sunshine.

Garden Tip #134

August is a good time to lift and divide your Bearded Iris, but don’t touch your Pacific Coast Native Iris until the rains return in fall. To learn more about the joys of growing this “Flower of the Rainbow” go to the American Iris Society’s website.

The King County Iris Society holds lectures and events throughout the year and publishes a monthly newsletter. Their annual rhizome sale is September 13 and 14 at Crossroads Mall 15600 NE 8th St, Bellevue. To join the society send $10.00 to KCIS Membership Chair, PO Box 95538, Seattle, WA 98145-2538. Online at www.kcis.org.

on pruning flowering bulbs

This is my first year planting spring flowering bulbs, which
grew nicely. I cut the dead flower and the stalk once it died back, and now the
foliage is yellow. What am I supposed to do with the yellow foliage? Pull it out? Cut it off? Just leave it alone? Also, will
planting some annual petunias now hurt the bulbs I have planted in the
garden? How close can I plant the petunia to the bulbs? I was going to
try and hide the yellow foliage.

 

The answer will depend on which bulbs you were growing. For example,
daffodil stems should not be cut back until at least 6 weeks after the
flowers have faded, and you should never tie the foliage in knots or
braid it (this is a common but ill-advised habit). You can leave
daffodils in the ground to naturalize and spread.

With tulips, you also need to wait at least 6 weeks from the fading of
the flowers before cutting back the leaves.

With hyacinths, you can pull away dead foliage and flower stems as they
fade. When the top growth has died down, you can either leave them in the
ground or dig up the bulbs, dry them off, and store them for replanting.

If you are growing iris, you can cut the dead flower stems to the base,
and cut away dead leaves in the summer. If they are bearded iris, the
fan of leaves may be cut back in the fall to about 8 inches above the
base.

(Source: The Plant Care Manual by Stefan Buczacki, Crown Publishers,
1993)

You can certainly plant your annual petunias quite close to bulbs like
daffodils and tulips and other bulbous plants which are quite vertical.
Just don’t plant right on top of the bulbs. To disguise dying bulb foliage, use perennial ground cover plants that keep their leaves over the winter, and that have stems soft enough for bulbs to emerge through them. Hardy geraniums (true geraniums, also called cranesbill) and creeping veronica, such as Veronica peduncularis ‘Georgia Blue,’ are good choices. You can remove dried leaves as needed, and they can be tidied or groomed in early spring.

plants for banks of a fish pond

We need some advice and we are hoping you can help. We would like to replant the banks of our fish pond and want to know what kinds of plants would hold a steep slope and be compatible with the fish and each other. We have a large deer and elk population and we get substantial amounts of rain. We like grass-type shrubs and we need a ground cover that will not take over and is evergreen.

 

From the research I have done, it seems that a pond with a sloping side is a very good idea, but if erosion is a serious issue, you may want to think about both plants and physical controls such as coconut fiber matting to stabilize the banks. The Brooklyn Botanic Garden’s guide (1997), The Natural Water Garden, has a description of using coconut fiber tubes (also called biologs) laid horizontally along a bank, which can also be used as a secure planting medium for seedlings.

As far as deer-resistant plants which may work for your site, iris and spiraea appear to be unappealing to deer, so you might want to try some of the irises which prefer moist situations, such as Iris laevigata, and Iris versicolor (blue flag), as well as Spiraea douglasii (hardhack).

Other plants which may help with preventing erosion are Lysichiton americanum (skunk cabbage), Athyrium filix-femina (lady fern), Carex obnupta (sedge), and Cornus stolonifera (red osier dogwood) or C. alba (red twig dogwood).

Some grassy or reedy plants which do well as marginal (water’s edge) plants include Acorus calamus ‘Variegatus’ (variegated sweet flag), Pontederia cordata (pickerelweed), Sagittaria latifolia (American arrowhead), and Typha latifolia (cattail). All of these are deciduous.

For evergreen plants, you could try Scrophularia auriculata ‘Variegata’ (water figwort), an evergreen perennial with cream-edged foliage. The flowers should be deadheaded to prevent self-seeding. Thalia dealbata (hardy canna) is evergreen, with long-stalked blue-green leaves and violet flower spikes.

Holden Journals

Holden journals book cover Holden Village is a Lutheran community center deep in the Cascade Mountains, accessible only by a boat ride on Lake Chelan followed by a bus ride on a mountain road. At 3,000 feet, it is very cold and snowy in the winter, and cut off from Wi-Fi and cell phone reception.

For some this may sound like paradise. It was for Peggy Haug and her partner (now spouse) Juanita, who spent two years there from 2005-2007. “Holden Journals: A Close Look at Nature in the North Cascades” is her record of the flowers and the birds she found in the village and on nearby hikes. Her drawings are augmented with copious notes of interpretation, bits of poetry, and her impressions of living in an isolated village.

This book is also an excellent field guide to the wildflowers, trees, and shrubs of this region and an impressive birding list – 68 species in the first year. Some of the most beautiful drawings are of the colorful leaves and berries of fall, intricately overlapping. It can take several delightful minutes just to read all the notes that she weaves in amongst the plant images.

While the native plants are the main features, Holden Village has surviving plant relics from the nearby former mining village, including daffodils and bearded iris. The latter were captured in an earlier book, “Holden Village Historic Iris“, reviewed in the Fall 2008 issue of “The Bulletin”.

Excerpted from the Fall 2018 Arboretum Bulletin.