Our Eyes on Irises

Now blooming: the magnificent irises.

Most often, you will see hybrid forms of the tall bearded irises. These plants are most popular among the 250 species of irises; hybridizers have been striving for decades to create imaginative new forms of the original plant, the German Iris (Iris germanica).

A comparison of the German Iris with any of today’s hybrids reveals a dramatic difference. The ancestor is an attractive but rather small, rather droopy flower on a short stem, with very few blossoms, usually an unexciting yellow or purple. The modern hybrid is much taller, with proud standards and horizontal falls, multiple stems and blossoms, and any of an astonishing range of colors—anything but true red—and combinations of colors.

The iris, named for the Greek goddess of the rainbow, has inspired legions of gardeners to collect and cultivate newly introduced hybrids and to share the rhizomes with friends (or customers). I have seen several private gardens with scores of different, striking tall bearded irises specimens, in a rainbow of colors, and a mere scattering of other plants. Only roses receive such dedication.

The popularity of the tall bearded iris can distract from other garden-worthy species in the genus iris. Indeed, at least 250 other species have been identified, each easily recognizable as an iris but with a unique look.

The principal groups of species irises are as follows:

Bulbous Irises

This group includes the Dutch, Spanish and English Irises (named most often for the country that popularized them, rather than the country of origin), and the Reticulata Irises (their bulbs have a reticulate or netted covering). Bulbous irises grow from bulbs, rather than from rhizomes.

Rhizomatous Irises

This group is most often hybridized, as already mentioned. The name refers to the colorful and fuzzy “beards” that decorate the falls. The beard serves no known function, but might attract pollinators.

There are two sub-groups of rhizomatous irises: bearded: dwarf, median, tall bearded, aril and arilbred (their seeds have an aril or “collar”); and beardless: Japanese, Louisiana, Pacific Coast, Siberian and Spuria irises.

Species Irises

There are many species irises, each with subtle differences. About eight are popular choices for home gardening. My garden includes an I. unguicularis, called the Winter Iris for when it produces light purple, fairly small blossoms, often hidden among an abundance of leaves. My specimen grew into a large clump, so yesterday I dug it out and used my dull garden hatchet to make four divisions of this Greek native for my Mediterranean Basin garden.

Crested Irises (botanically between bearded and beardless) and Tender Crested Irises (orchid-like blossoms; can be grown warmer spots of the Monterey Bay area).


To learn more about irises…and especially options beyond the popular tall bearded irises…visit these websites:

An excellent (and fairly recent) book for a wealth of information is
Claire Austin’s Irises: A Gardener’s Encyclopedia (Timber Press, 2005).




Succulents for Your Garden

Describing trends in gardening is difficult because no clearinghouse reveals what home gardeners find appealing these days. We might find sales data from suppliers of plants, seeds or other garden products, but that could be biased by commercial priorities (not there is anything wrong with that!).

Another source might be garden-related articles in newspapers and magazines. Garden writers might just invent seasonal trend, so we should ask for reliable information that provides the basis for such claims.

With those disclaimers, I will report a trend that others have declared: that home gardeners in America are demonstrating increased interest this year in edible gardening.

This renewed enthusiasm for growing fruits and vegetables might be documented with sales data, but while the claim is credible, I haven’t seen the supporting facts. The believability of the trend rests on some combination of recession-inspired desire to control food costs and the appeal of freedom from chemicals and industry-inspired hybrids that ship and store well, but lack taste.

Another trend that also lacks documentation, but still rings true, is the gardener’s embrace of succulent plants. This claimed trend is based on the minimal challenges of growing succulents, their minimal—but significant—need for irrigation, and the stunning range of texture and colors in their foliage and blossoms.

To review, “succulents” include all plants that store moisture in their leaves, stems or leaves. Such plants exist within many different genera, so they are not related botanically, but all have adapted to low-moisture environments.

Succulents include cactuses, which typically are spiny and members of the genus Cactacea. They have much appeal, but can be hard to handle.

The vast majority of succulents do not have spines, and store moisture above ground, in their stems or leaves.

Some, called geophytes, survive dry periods by dying back to underground storage organs. Geophytes satisfy the definition of succulents but are not always regarded as succulents. That seems motivated more by established practice than by botanical science.

The specialized organs of geophytes include the following:

• true roots (of a dahlia or carrot);

• modified stems (the corm of a crocus, the stem tuber of a potato, the rhizome of a bearded iris, the pseudobulb of some orchids, or the caudex of the Adenium);

• storage hypocotyl or tuber (of a cyclamen); or the

• bulb (of a narcissus, lily or onion).

To see a variety of succulents, visit the annual show and sale of a local cactus and succulent society. California’s central coast region, for example, has the Monterey Bay Area Cactus and Succulent Society. This group’s annual show and sale in 2012 occurred on April 28 and 29 in the garden area of Jardines Restaurant, in San Juan Batista. This event offers a consistently impressive show, good prices for plants, a satisfying Mexican lunch at Jardines and another fine opportunity to enjoy gardening.


Visit the extensive website of the Cactus and Succulent Society of America. This website’s many resources include links to local affiliates. (There are twenty-five in California alone!) Also, see the Events Calendar for national, regional and local events, plus a selection of international events.

A well-regarded book on growing succulents in containers is Debra Lee Baldwin’s Succulent Container Gardens: Design Eye-Catching Displays with 350 Easy-Care Plants (Timber Press, 2010)

Search for “cactus and succulent” books on Amazon.com, or visit your local library.


California’s Best Public Garden

My recent travels included an April Fool’s Day visit to the Huntington Botanical Gardens in San Marino (near Pasadena). I visited this extraordinary garden before, but not for several years, and was pleased that it continues to develop and to delight.

The Gardens, spread over 120 acres, include numerous thematic areas, several of which are “world-class” gardens: some oriented to geographical regions (Japan, China, Australia, etc.), some focusing on categories of plants (roses, palms, cacti & succulents, herbs, etc.) and others emphasizing garden-related topics (Shakespeare Garden, Children’s Garden, Jungle Garden, etc.) Something for every gardener!

One of my favorites, the Japanese Garden, was closed through spring 2012 for renovation. A nearby part of the world was represented, however, by the new Chinese Garden, “Liu Fang Yuan, the Garden of Flowing Fragrance,” which was opened in 2008. This a spectacular garden includes twenty-four poetically named features, e.g., Love for the Lotus Pavilion, Isle for Welcoming Cranes, and Bridge of Strolling in the Moonlight. Already fascinating for its specimen plants, architectural design and scenic views, it is still evolving with support from numerous donors.

My companions for the day, a Master Gardener and spouse from Tuscon, were most interested in the Desert Garden, which includes cacti, succulents and other zerophytes. It is unquestionably one of the world’s finest gardens of its kind, with specimens of more than 5,000 species from many continents. The garden began in 1907-08 with a half-acre of cacti and succulents from Mexico, and by 1981 grew to its present ten acres.

The Desert Garden includes sixty plant beds, with areas dedicated to Old World plants, North America, the low southeastern part of South America and South Africa.

One plant I found intriguing was the Chilean Puya alpestris, related to the young Puya berteroniana (“Blue Puya”) in my garden. This succulent produces “six- to ten-foot flowering spikes of metallic, deep turquoise flowers highlighted by vivid orange stamens in summer.” The Huntington’s large collection of these “otherworldly” plants was not in bloom during our visit, but it had numerous stalks with buds ready to open. Fortunately, there were many other plants in bloom for us to enjoy.

We also toured the historically oriented Rose Garden, which has nearly twelve hundred species and cultivars on display. Our visit was early in the season, but many roses were already in bloom, providing a generous sample of the species and hybrids of the much-loved rose.

There are other fine public botanical gardens and arboreta in California, but the Huntington Botanical Gardens is larger, more diverse and better maintained than any others that I have visited.

If the opportunity arises for you to visit the Los Angeles area, schedule at least a day to visit the Huntington Gardens.


The full name of this impressive resource is The Huntington Library, Art Collections, and Botanical Gardens. As the name indicates, the site includes

  • A research library of some six million rare books and manuscripts in British and American history and literature, including an exhibit hall where visitors can see such literary treasures as Chaucer’s Canterbury Tales, a Gutenberg Bible on vellum,  an enormous (“double elephant”) folio edition of Audubon’s Birds of America, and much more.
  • An extensive art collection, displayed in three buildings:
    • The Huntington Art Galley has on of the finest collections of European art in the nation;
    • The Virginia Steel Scott Galleries of American Art include American art from the colonial period through the middle of 20th century; and
    • The MaryLou and George Boone Gallery hosts changing exhibitions.
  • The Botanical Gardens, with their many thematic areas, over 120 acres.

There is much to see and appreciate. While you might visit “The Huntington” primarily for the gardens, include some time to see its library and art resources as well. Here is the link to The Huntington’s website, where there is all the information you will find useful.

A Rose by Any Other Name…

At least one gardener has been motivated by my recent recommendation to learn the botanical names of plants in your garden. Wendy in Monterey wrote, “We’d like to turn over a new leaf and start learning the names of our plants. Can you recommend a book that would help us—with color photos, scientific and common names, and maybe a paragraph about the plant. We live in Monterey CA and have a variety of shrubs, trees, grasses, perennials, annuals, and rocks! Many thanks.”

My immediate recommendation is to get the 9th edition of Sunset’s indispensable reference, The Western Garden Book. This very recent publication includes hundreds of additional plants and illustrates plants with photographs instead of line drawings.

Finding a good information source is just the first step toward progress. Here are three ideas to make learning plant names more enjoyable.

1. Understand how plant names relate to other plant names

Plant names include two basic parts: genus and species. For example, Ceanothus griseus is the name for the Carmel Ceanothus, a native of the Monterey Bay area and one of dozens of species within the genus Ceanothus.

A given species might include varieties. In this case, we have Ceanothus griseus, var. horizontalis, with the common name Carmel Creeper.

A species or a variety within a species might include cultivated varieties, called “cultivars.” These are natural variations that have been selected for propagation because of their desirable features. The Carmel Creeper’s cultivars include ‘Yankee Point’ (narrower leaves and darker blue flowers) and ‘Diamond Heights’ (yellow and green variegated leaves, pale blue flowers).

Every genus also exists within a family. The genus Ceanothus is one of more than 50 genera within the Buckthorn family (Rhamnaceae). A family relative of the Ceanothus is the Rhamnus californica, the California Buckthorn or Coffeeberry.

2. Accept the reality that plant names change.

Taxonomists change plant names on the basis of DNA analyses and other methods. They either combine or separate genera (or other categories). Our current example, Ceanothus griseus has been changed recently to Ceanothus thyrsiflorus var. griseus.

Changes reflect refinements, so don’t fret!

3. Appreciate the meaning of plant names.

Many plant names describe a plant’s appearance. The genus name Ceanothus comes from the Greek “keanothus,” that referred to some spiny plant, and the species griseus is the Latin word for “gray.”

Some plant names refer to the plant’s discoverer. For the plant Salvia karwinskii (Karwinski’s Sage), the genus name comes from the Latin salveo, “I am well,” and the species name refers to the 19th century German explorer Wilhelm Friedrich Karwinsky von Karwin.

There are several books on the derivation of plant names. An online source is Michael Charters’ website, “California Plant Names: Latin and Greek Meanings and Derivations (www.calflora.net).


I have just received my copy of Sunset’s 9th Edition of The Western Garden Book, and it doesn’t disappoint.

I have several previous editions of this very useful publication, so I could attempt a detailed historical analysis of its content, but I won’t because I prefer to address the here and now.

The section on Climate Zones has been expanded to include information for several western states. That broadens the market for the book, but I’m still most interested in the climate zone of my own garden and care little about what’s happening in New Mexico.

Every gardener should know the climate zone of his or her garden, the micro-climates within the garden and the composition of the soil.

The next section, called the Plant Finder, has lists of plants in three categories: Problem-solving Plants, Earth-friendly Plants, and Plants for Special Effects. These sections are valuable guides to the alphabetical list of plants (the book’s main section). Unless you already know the name of a plant, an alphabetical list can be frustrating. The Plant Finder helps the gardener find a plant for a given situation.

The last major section, Gardening, Start to Finish, provides brief landscaping and cultivation information. This is helpful, but a serious gardener will need more detailed information on these topics.

Finally, the book restores the index of common and botanical names. This index was missing from the previous edition, in favor of a novel approach to including common names within the main alphabetical section.

The new Western Garden Book is available through most bookstores, garden centers and Amazon.com (which has the best prices, as usual). I paid for my copy, so this brief review is unbiased, except by my previous reliance on this essential reference work.

Every serious California gardener’s library should include a well-read The Western Garden Book!


Tom Karwin is a Santa Cruz resident; a UC Master Gardener; a member of several garden groups; and board member of the UCSC Arboretum Associates.