Spring is the Time for New Plants

The first day of spring, astronomically speaking, will arrive on March 20th. It’s time to think about planting for the spring.

Actually, as we’ve noted more than once, the fall months are the best time for planting, to allow time for root development before the warmth of spring awakens the plants. The coming of spring might be regarded more as the traditional time for planting because that’s when the first tastes of warm weather awaken the gardeners.

The garden centers and online nurseries are oriented to the spring rush of gardeners seeking a few floriferous features for their gardens. The surge of mail-order catalogs and magazine galleries of new introductions manifests this orientation.

It can be quite interesting to peruse the new plants that are offered at this time each year. There are many familiar favorites, but the real headliners are plants that have been recently discovered by plant hunters or created by hybridizers.

Some plant hunters roam the globe in search of garden-worthy plants that have not been seen in their natïve lands. The history of gardening includes a long list of plant hunters who have served to relocate plants from exotic places to the gardens of Europe and, more recently, the United States. The best known of the contemporary plant hunters is Daniel Hinkley who shares his travels and horticultural discoveries in his books and articles in Horticulture magazine and other periodicals. Check out his website.

Plant hunting doesn’t always require traipsing through distant lands. New discoveries also can be made by close observation of large groups of plants in cultivation. As plants pollinate each other, potentials exist for mutations or “sports” to appear with novel characteristics. Because these natural changes are random rather than evolutionary, they will include a significant percentage of uninteresting innovations, but occasionally a natural mutation results in a desirable variation of a familiar plant. Then, the grower’s role is to propagate the newcomer to produce enough plants for commercial distribution, come up with an appealing name for the plant, and introduced it into the trade.

A third approach to developing new plants involves hybridizing. The process is quite simple, at its core: the hybridizer selects two plants of the same species with different but desirable traits. For example, one might have a good blossom color and the other might have strong stems. The hybridizer transfers pollen from one plant to the other, plants the seeds that result from this mating, and examine the seedlings for the desired combination of traits. Typically, the hybridizer will reject many of the seedlings as unsuccessful relative to the objectives, and, with luck, will find one or more successful results. These are propagated further for commercial distribution.

Given the uncertain outcomes of this process, it requires time, patience, and good record-keeping to result in a financial payoff.

This brings to mind the secret to making a small fortune in the plant breeding business: begin with a large fortune.

The process of finding or creating new plants always targets the individual gardeners who want to add the latest introductions to their gardens. One that has caught my eye is a Sempervivum hybrid ‘Gold Nugget’, available from ChickCharms, which specializes in collectable hens & chicks. It’s a little pricey but quite striking.

Sempervivum 'Gold Nugget'

Sempervivum ‘Gold Nugget’






The gardener might enjoy bringing new introductions to the landscape but could also stay with familiar and reliable options. Either way, enjoy your garden!

The Bold Dry Garden

Book Cover

It’s not often that we see a new book about a garden that’s both famous and near enough for a one-day visit. We now have The Bold Dry Garden: Lessons from the Ruth Bancroft Garden (Timber Press, 2016), written by Johanna Silver, with historic photographs and excellent new photographs,

This is a three-acre garden in a residential neighborhood, packed with over 2,000 cacti, succulents, trees and shrubs. Visiting is not a sprawling and overwhelming experience, with too much to take in without camping out, or an extended visit. Instead, it offers a relatively compact display of a wide variety of succulent plants.

The book begins with the garden’s history. Ruth Bancroft developed this garden at her home in Walnut Creek, beginning in the 1950s. Like all personal gardens, it began tentatively, with the purchase of few small plants, and grew slowly as the owner’s interest deepened and her vision broadened.

By the early 1970’s, Ruth was ready to map out her future garden. She brought in garden designer Lester Hawkins, to draw the setting for a dry garden, and to recommend plants to add to her growing collection. The initial planting was accomplished formally in 1972, although Ruth had already collected a significant number of plants.

The plants grew in number and size, and the collection grew in sophistication and beauty. It deeply impressed, Frank Cabot, a nationally prominent gardener from the Quebec area, who became concerned about preserving the garden into the future. In 1989, he founded the Garden Conservancy with the goal to preserve exceptional private gardens, with preservation of the Ruth Bancroft Garden as its first objective. By 1994, the Garden’s site was officially transferred to a non-profit corporation, Ruth Bancroft Garden, Inc., dedicated to maintaining and improving the garden, and to make it available to the public.

Today, Ruth Bancroft is recognized as a dry gardening pioneer and innovator. She has reached the age of 107 and she maintains her love of her collection.

The longest chapter of The Bold Dry Garden, “Signature Plants of the Dry Garden,” describes and pictures garden’s diversity, organized in sections: The Smallest Players, Aeonium, Crassula, Echeveria, Haworthia, Sedum, Sempervivum, the Importance of Rock, Architectural Elements, Agave, Cactus, Yucca and Other Swords, Flowers and Foliage, Aloe, Euphorbia, Gasteria, Protea, Terrestrial Bromeliads, The Softer Side, California Natives, and Trees. Whew!

Reading this fine book can be a pleasant introduction to the world of succulent plants. Visiting this extraordinary garden is an opportunity to see many different forms of these plants, and to become inspired to develop your own collection…and to come again to the garden.

For more about this garden, and everything you need to prepare for a tour, visit the garden’s website.

The Garden Conservancy is both a preserver of private gardens and guide to seeing them through its Open Days program. Browse to the Conservancy’s website for more information.

The long-time curator of the Ruth Bancroft Garden, Brian Kimble, is scheduled to speak at the Monterey Bay Area Cactus & Succulent Society on Sunday, March 19th. See the Society’s website for details.

The Bold Dry Garden is a good read for any gardener, excellent preparation for a visit to the Ruth Bancroft Garden, and a fine addition to any library of garden books.

Controlling Annual Weeds


The gardener’s war on weeds cannot be ignored at this time of the year, as cool-season annual weeds respond to the current temperatures and recent rains. By popping up in our gardens.

The weeds in front of us always command immediate attention, but they also encourage a broader view of weeds. Let’s review the sources of the problem and the strategies for weed control.

The first step in control involves knowing the three broad categories of weeds: annuals, which are usually the most troublesome, and biennials and perennials, which we will consider on another day.

Annual weeds are those that grow and die in one season. This cycle begins with seed germination and ends with the dispersal of a new generation of seeds.

Annual weeds include two sub-categories: summer and winter annuals, which are also referred to as warm season and cool-season annuals. The names of weeds in each of these groups could be identified, but their botanical or common names are less important than their life cycle.

After Annual Weeds Sprout

Cool-season annual weeds germinate from seed in the late summer or early fall. They grow during the winter, flower, set seed and die from heat in the late spring or early summer. This approximate calendar guides actions to reduce weed growth in the garden. Right now, these pesky plants have already germinated, so the appropriate action is to minimize the production and dispersal of seeds. Do this by removing the flowers as soon as they appear. Depending on the circumstances and other factors, this can be done by plucking the flowers, mowing the weed batch, or pulling the entire plant.

Warm-season annual weeds germinate and grow in the spring, and thrive throughout the summer and into the early fall. They will die by frost, however, in the Monterey Bay area, where frost comes later if at all, these plants can persist for quite a while. Controlling warm-season weeds after germination uses the same techniques outlined above: minimize the spread of new seeds by removing the flowers or the entire plant before, or as soon as, the flowers appear.

Up to half the weeds that are pulled from the garden are still capable of dispersing seeds, so the safest plan is to dispose of them in the green waste. They could be added to a compost bin, but only if your compost maintains a temperature of 160 degrees Fahrenheit or more for three hours or more, the seeds won’t survive.

Before Annual Weeds Sprout

Methods to minimize the production and dispersal of seeds are highly recommended, but inevitably some seeds will make their way into in your garden. Seeds will arrive from weeds that already grow there, or are brought in by the wind, by the dropping of birds, or by hitching a ride on people’s shoes or clothing, animal’s fur, or imported plants, even plants from a garden center. The result of these several sources is the weed seed bank tat exists in all gardens.

All seeds require light and moisture to germinate, so the basic method for discouraging the germination of seeds already in the garden begins with mulch. Two or three inches of organic mulch will deny the seeds light, and most will not be able to sprout.

Viable seeds can remain in the soil for years, waiting for light and moisture. They might be surprisingly deep in the soil. The best plan is to let sleeping seeds lie. The worst plan is to dig up the soil to give the seeds access to light and moisture. If you need to dig up your garden, even to install a new plant, cover the exposed soil immediately after with mulch. Mechanical tilling of the soil will reliably produce a new crop of weeds.

In addition to mulching, close placement of desirable plants also will deny light and moisture to the dormant seeds. In many cases, a closely planted bed is also attractive.

Also, controlling access to moisture with drip irrigation, while controlling access to light with mulch and landscape plants should minimize weed growth significantly.

Finally, let a few weeds grow. You are unlikely with a goal of complete eradication of unwanted plants, and there is some value in the contribution of weeds to the flora and fauna of the garden. In any event, a casual (but systematic) approach to weed control allows you to relax in the garden.

Cold, Rain, and Buttercups

We have had welcome rains, and apparently we should expect more around the time that this column appears. That’s good, but that weather prompts some salient observations.

First, although the drought has been broken for the present, we should regard the present period as a hiatus, rather than an end to dry times. Long-term projections still indicate below average rainfall in future years,

Most importantly, our aquifers were depleted significantly during the drought years, and replenishing them will require many years of at least normal rainfall. We will have to wait for encouraging reports on that front.

Meanwhile, examine your garden for possible negative impacts from the recent cold and rainy days. The plants in my garden are nearly all native to California or other summer-dry (Mediterranean) climates, so they managed well during the dry days.

One exception was a mature Chilean Myrtle (Luma apiculata) that succumbed to the drought, and had to be removed.

That experience recalls a thoughtful comment by Alexander Graham Bell: “When one door closes, another opens; but we often look so long and so regretfully upon the closed door that we do not see the one which has opened for us.” In this case, the tree had grown larger than expected and closer to the house than wanted, so while I regretted its loss, its absence opened space for new plants.

Almost all my succulent plants shrugged off the cold spell, with the exception of a Foxtail Agave (Agave attenuata), which I had been growing in a large container. I planned to plant it in the ground eventually, to provide the space it will need to reach its full size of four feet high and eight feet wide. The plant’s rosette is quite attractive and dramatic, but its distinctiveness is based on its flower stalk, which grows five-to-ten feet, reflexes to the ground and then arches upward again. I learned too late that this plant is unusual among Mexican native succulents for its susceptibility to cold weather. I should have covered it, or brought it inside. It lost some leaves, but now appears to be coming back.

I have been taking advantage of the fine weather between rainstorms by catching up (with help!) on the seasonal weeding tasks. This work includes the annual battle with Bermuda buttercup (Oxalis pes-caprae), a South African native that thrives in California’s coastal gardens, and opens its bright yellow blossoms in late winter or early spring.

Bermuda Buttercups

Bermuda Buttercups

I have been puzzled by the relentless and random spread of this annoying plant. The explanation on UC’s Integrated Pest Management website (ipm.ucanr.edu/) has been incomplete:

“Viable seed never has been documented in California, and rarely has it been seen anywhere else in world. Foliage dies and the bulbs become dormant when temperatures rise in late spring and summer. Bermuda buttercup reproduces vegetatively by bulbs and spreads when plants are divided or soil containing the bulbs is moved to un-infested areas.”

I have learned that this plant is tristylous, an uncommon morphology meaning that it has three flower shapes (morphs). All the flowers on a given plant will have the same shape, but the pollen from a flower on one morph cannot fertilize another flower of the same morph.

Tristyly does not necessarily affect the propagation of the Bermuda buttercup, but it might explain its spread in gardens, and provide a clue to its management. The search goes on!

Meanwhile, we continue with weeding and mulching, and preparing to enjoy the garden in the spring.

Planning for Summer “Bulbs”

We are approaching the window for planting summer-blooming bulbs, so it’s time for planning

Summer-blooming bulbs might be called “spring-planted bulbs,” just to be confusing.

For clarity, geophytes, i.e., plants that have underground organs, are grouped in just two categories: spring-planted/summer-blooming, and fall-planted/spring-blooming.

Because plants often do not always follow our categories strictly, blooming seasons include early, mid and late bloomers. Good catalogs and labels will identify a plants bloom season, for reference in planning extended periods of color in the garden.

In the Monterey Bay area’s moderate climate, summer bulbs could be planted anytime between February and April. It’s now too late to plant spring-blooming bulbs.

Many gardeners call all geophytes “bulbs,” but they actually include several kinds of specialized storage organs:

  • True roots: tuberous roots (Dahlia) and storage taproots (carrot)
  • Modified stems: corm (Crocus), Stem tuber (potato), Rhizome (Iris), Pseudobulb (Pleione), Caudex (Adenium)
  • Storage hypocotyl or tuber (Cyclamen)
  • Bulb (Narcissus, onion)

Here is a sampling of popular summer-blooming “bulbs:”

  • African Lily (Agapanthus)
  • Amaryllis (Hippeastrum)
  • Canna
  • Cape Coast Lily (Crinum)
  • Dahlia
  • Ginger Lily (Hedychium)
  • Gladiolus
  • Lily – Asiatic, Oriental, Species, Hybrids (Lilium)
  • Montbretia (Crocosmia)
  • Peruvian Lily (Alstroemeria)
  • Windflower (Anemone coronaria)

Consider planting uncommon “bulbs,” to bring variety into the garden:

  • Chinese Summer Ground Orchid (Bletilla, a terrestrial orchid)
  • Glory Lily (Gloriosa superba)
  • Guernsey Lily (Nerine)
  • Indian Crocus (Pleione, another terrestrial orchid)
  • Pineapple Lily (Eucomis)
  • Rain Lily (Zephyranthes)

Planting guidelines for all geophytes: locate in full sun; select a well-drained bed (underground storage organs could rot in soggy soil); choose plants that are best for your climate; and amend with compost or aged manure for tallest, lushest and healthiest plants.

When selecting plants, check the storage organ for good health. This check can be done easily with dormant bulbs, which might be marketed in plastic baggies, and small potted plants can be lifted gently from their pots to examine their health. If the organ looks black, unusually soft, or otherwise troubled, leave it behind and consider shopping elsewhere.

Summer bulbs can be found now or in the next few weeks at local garden centers. As always, specialized mail order suppliers have online and printed catalogs with larger selections. Here are three to consider:

Brent and Becky’s ((877) 661-2852)

McClure & Zimmerman (800) 883-6998)

John Scheepers, Inc. ((860) 567-0838

Prepare now for color in the summer garden. As always, planting in odd numbers of three or more—if you have space—creates the most attractive displays.

Enjoy your garden!

The Future of Retail Garden Sales

We have seen the Internet’s impacts on many aspects of society, such as music distribution, newspaper printing, television and radio broadcasting, and too many other fields to list.

Retail marketing is among those other fields that have been disrupted by the Internet, and the marketing of plants for home gardening could be transformed by this technology on the future.

We might have fond recollections of shopping for plants as the experience of browsing through our favorite independent garden center, seeking inspiration and friendly advice. While that form of retail marketing of plants still exists for most gardeners, two major changes have already occurred.

First, is the emergence of mail order plant sales, which I have often mentioned. Local garden centers typically provide a valued service by offering regionally appropriate popular plant selections on a seasonal schedule. By comparison, their mail-order competitors offer dramatically wider selections and the convenience of home delivery. The downside of acquiring plants in this way is that the gardener doesn’t have an opportunity to see the plant before it shows up on the doorstep. With reputable suppliers, however, the delivery will be a well-grown, disease-free plant, exactly as ordered.

A great and growing variety of mail-order suppliers has developed. Their advertisements and web addresses can be found in the pages of garden magazines. A useful directory of mail order plant suppliers is available online, in Cyndi’s Catalog of Garden Catalogs. To find sources of California native plants on this website, click on “Native Plants,” then search for “California.”

Anther strategy is to search for a specific botanical name

Wholesale growers have begun offering their plants by mail, sometimes at prices below those found at retail outlets. The retailers do not appreciate being bypassed in this manner, particularly since they provide gardeners with drop-in facilities and personalized attention.

In some cases, wholesalers collaborate with retailer garden centers through an arrangement called BOPUS (Buy Online Pick Up in Store). This works particularly well for after-hours orders.

Another alternative to the independent garden center includes the big-box stores, also called superstores. These are physically large retail establishments, usually part of a chain. Attractive prices can be found, while the care of plants can vary depending on the location. A report in the current issue of Nursery Management magazine indicates that big box stores have garners 83 percent of plant sales, with the remaining 17 percent going to independent garden centers.

The future of garden plant sales could involve a combination of the buying power of big-box stores, the efficiency of mail-order sales, and the marketing technologies of the Internet. As we order through e-commerce giants like Amazon, Netflix, and others, we see increasing applications of predictive analytics and artificial intelligence, with which the seller uses our previous purchases and perhaps our profile information to suggest which plants to buy. We have already seen experiments with the seller’s use of FaceTime technology to help gardeners to decide where to plant and what to plant.

Another stage in this line of development is “Uber of Landscapers” concept, in which the seller uses Internet technology also connects the gardener with a local landscaper to install and maintain the plant being purchased. Amazon Services has already bought a company that uses a mobile app to send landscapers directly to users’ homes.

In the not-too-distant future, the home gardener might use a smartphone to show a neglected corner of his or her garden to remote plant supplier, and ask, “What would look good here?” After a bit of dialog, the supplier recommends one or more plants, the gardener orders one, and the supplier provides a referral to a local landscaper for the installation. If the gardener has ordered many plants, or perhaps a larger shrub or tree, he or she might add installation to the plant order, and negotiate the schedule.

As this brave new world of gardening arrives, I trust that we could order plants that have been certified as organically grown and pollinator-safe.

Charlie Keutmann atThe Garden Company

Charlie Keutmann at The Garden Company, in Santa Cruz

Photo by Dan Coyro, Santa Cruz County Sentinel



Gardening by keyboard has certain benefits, but it will not replace the direct experience of walking through one’s own garden or the local garden center to plan future additions.

Soil is the Solution

A crucially important trend in climate change news focuses on soil.

In the United States, the greatest contributors to climate change have been the energy and transportation sectors, so federal responses have focused on emissions that result from burning fossil fuels. The resistance to regulated changes has come from private interests with business models that depend on fossil fuels (and politicians that support them).

The U.S. priority on fossil fuels makes sense, and it engages a good fight, but it’s not the entire story.

For at least the past ten years, public interest organizations have been pointing to Nature’s plan for moderating climate change. That plan depends on forests and soils, both of which are very good at absorbing and storing (sequestering) carbon.

Climate change has been accelerated by cutting down vast areas of forest to free land for agriculture. The negative effects of deforestation have been recognized, and initiatives (never enough) have been launched to control this practice and let the trees do their work.

Nature’s plan also as been compromised by agricultural practices, beginning with deforestation and continuing with a variety of poorly conceived land-use and land-management practices.

The good news on this front is that almost all the countries that have joined in the Paris Climate Agreement have stated that they will improve agricultural practices in their efforts to curb climate change.

According to the World Resource Institute, agriculture contributes 13 percent of greenhouse gas emissions and, with land-use changes, 24 percent of net emissions.

Agriculture is not as important as a climate change factor in the U.S. as I developing countries, but it’s still a significant contributor. California, which has a huge role in agriculture, has recognized this reality and initiated the Healthy Soils Initiative, discussed in a recent column (see ongardening.com/?p=2680) .

In this regard, California has been well ahead of the federal pace: U.S. Department of Agriculture has recommended that farmers voluntarily adopt carbon-capturing practices, but has done little more in deference to policies on energy and transportation.

In more good news, the U.S. position is changing, In December of 2016, the National Science and Technology Council (NTSC) released the report, “The State and Future of U.S. Soils: Framework for a Federal Strategic Plan for Soil Science.” The NTSC is “is the principal means by which the Executive Branch coordinates science and technology policy across the diverse entities that make up the Federal research and development (R&D) enterprise.”

To see this report, visit www.whitehouse.gov and search for “soils.”

In related actions, on January 11th, Regeneration International, a coalition of consumer groups, launched its “Soil is the Solution” briefing for members of Congress. A team of experts will seek opportunities to talk to our elected policy-makers (or their staffs).

Also, on January 19th, Former Vice President Al Gore will unveil a sequel to “An Inconvenient Truth,” his 2006 climate-change documentary. The new film surely will emphasize the role of agriculture in climate change. The sequel will debut at the Sundance Film Festival, and will be released in theaters later in 2017.

Efforts to control climate change must begin with large-scale actions, but they are also appropriate for home gardeners. We all have a stake in the future!