Garden Faire Celebrates Sustainable Gardening

The first day of summer, June 21st, approaches rapidly, marking an annual astronomical event (the Summer Solstice), the annual Garden Faire (more about that below), and perhaps a time for gardeners to review their calendar calendars.

For each year since 2005, the Garden Faire has convened in Scotts Valley as a regional celebration of sustainable gardening, water conservation, and healthy living, The program varies a bit each year, but there are certain constants:

First of these is consistent—and greatly appreciated—support of local water providers, specifically the San Lorenzo Valley, Santa Cruz, Scotts Valley, and Soquel Creek water districts. Their interest in the Garden Faire reflects official reports that close to 50% of residential water use happens outdoors, largely for garden irrigation. That usage is ok when it is done wisely, which generally includes:

  • Using landscape plants that are appropriate for the local environment, particularly plants that are native to California or at least to our summer-dry climate, and avoiding tropical climate plants that require a lot of water; and
  • Providing only the amount of water that plants need, by using drop irrigation, turning off irrigation after a rainy spell (or during!), and directing water to the plants rather than to paved surfaces.

Water conservation makes sense during periods of drought and is always good practice. Drought considerations could return at any time, so we should make wise water usage a matter of habit. Our payoff comes in the form of smaller water bills.

Our water districts also prioritize the protection of the watershed. As we consider the water cycle, we appreciate the importance of keeping synthetic chemicals out of our groundwater. For gardeners, good practice means using only organic fertilizers, herbicides, and pesticides in the landscape. These products are best for our water supply as well as for the quality of our soils and the wellbeing of all forms wildlife: mammals, birds, insects and, lest we forget, the incredible diversity of organisms that make up the soil food web.

Gardeners and water providers have common interests: practices that are consistent with water conservation and watershed protection are also strongly preferred for garden cultivation.

This year’s theme, “Cultivating Community in Times of Change,” a variation on previous themes, emphasizes timely and interconnected issues: growing plants and society, and the opportunities and challenges of current environmental and political conditions.

The Garden Faire presents messages along these lines in various ways, without preaching. The event includes knowledgeable Main Tent speakers on various aspects of sustainable gardening, in the Main Tent, and Nutrition Tent speakers on healthy foods. The Faire also includes vendors that have been selected for their compatibility with the Faire’s theme, and that offer a variety of garden-related products and services. Community groups also participate in offering information related to sustainable gardening and healthy living.

The occasion also includes musical entertainment and healthy food choices. All these elements combine to provide a pleasant, low-pressure environment to celebrate gardening, learn a bit about sustainability, and enjoy a sunny day among friendly members of the regional community. For more information, visit the Garden Faire’s website.

The Garden Faire is a free-admission event, made possible by local sponsors, modest fees paid by exhibitors, and a hard-working team of volunteers. Still, you will want to be prepared to purchase plants for your garden.

IF YOU GO

What: The 12the Annual Garden Faire

Who: The Garden Fair, Inc., a non-profit corporation.

Where: Skypark, Scotts Valley

When: 9:00 to 5:00, Saturday, June 17, 2017

Cost: Free admission, free parking.

Information: http://thegardenfaire.org

Destroying Petunias

In mid-May of this year, flower nurseries throughout Europe and the United States destroyed uncounted thousands of healthy flowering plants, in compliance with government orders.

This might shock gardeners, but it could the right move.

This story began thirty years ago at the Max Planck Institute in Germany, when genetic engineers inserted a maize gene into petunias, leading to the development of a petunia in a color that petunias do not produce in nature: orange.

These studies did not result in the introduction of unusual new petunias, however, because government regulations in Europe and the United States require extensive analysis of the possible risks of GE organisms on human health and the environment. The orange petunia’s market potential was not great enough to support the additional expense of such studies, so the novel hybrids were not introduced, and the lessons learned were just added to genetic engineering’s growing library.

In 1995, other plant scientists reported that this genetically engineered (GE) orange color and its variations could be passed on to hybrid petunias through conventional sexual propagation.

Although this information was announced without fanfare, plant breeders used the orange petunia cultivar, during a period of several years to produce and introduce a variety of petunias with shades of orange. These new hybrids were treated like any new plants and not reviewed for safety or submitted for regulatory approval either in Europe or the United States.

In 2015, a plant biologist who had studied plant pigments at the University of Helsinki noticed orange petunias at a train station. He remembered the original genetic engineering experiments, tested a sample of the plants, and reported that they contained foreign DNA. In brief, they were GE organisms that had not been approved by government regulators. They were illegal flowers!

The word got out. In April of this year, Finland’s food safety authority, EVIRA, identified eight illegal petunia varieties and called for their removal from the market.

May 25th of this year, the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) identified nine varieties of GE petunias with orange, red or purple blossoms, and told growers and sellers to withdraw these plants from distribution and to dispose of existing plant by burning, sterilizing in an autoclave, burying them deeply, or composting. Seeds of these plants are to be disposed of by these methods, or by grinding. APHIS has identified eighteen potentially GE petunias that could be added to the disposal list.

APHIS advises: “Consumers who may have purchased GE petunias need take no action, as the petunias are not considered to pose a risk to human health or the environment.” Petunias are annual plants and will not last beyond the current season.

What is the significance of this regulatory action? APHIS has not found that GE petunias are threats to human health or the environment (as plant pests or noxious weeds might be designated) but wants them destroyed because they are unauthorized. They are unauthorized because the developers have not provided sufficient evidence to prove their safety, and petitioned for unregulated status. They have not done so in that past because they may have known that the plants contain foreign DNA, and probably won’t do so in the future because of the time and cost involved in formal testing.

The practical consequences of this regulation could be that GE improvements in ornamental plants, such as blossoms with novel colors, or greater size or abundance will not be available to gardeners specifically because of the cost of regulatory approval. We won’t see orange petunias or clear red irises or blue roses or any other cultivars that have eluded plant breeders.

We may be comforted that the genetic engineers will focus their efforts on organisms with large market potentials, and regulators will continue to do their work. Some scientific achievements, like creating the orange petunia, provide only interesting distractions, while others could generate unseen and unintended dangers to our health and the environment.

With tradeoffs like that, our gardens can do fine without orange petunias.

Mosses & Bryophytes

Learning about flowering plants (angiosperms) can be a lifelong study for a gardener. One report states that they include 416 families, approximately 13,164 known genera and about 295,383 known species. Angiosperms are within the group called vascular land plants, i.e., plants that have specialized tissues for conducting water and minerals throughout the plant, and for conducting the products of photosynthesis.

Other kinds of vascular land plants include clubmosses, horsetails, ferns, and gymnosperms (e.g., conifers). Seaweeds and other plants that grow in water (aquatics) are in a different group.

The scientific term for vascular land plants is Tracheophytes, a name with the same root as our own windpipes (trachea). The suffix “–phytes” means “plants.”

The complement to vascular land plants could be non–vascular land plants, which do not have the specialized tissues of vascular plants, and that have very different ways to grow and propagate. For example, instead of roots they have rhizoids, which are similar to the root hairs of vascular plants.

Non-vascular land plants, called Bryophytes (“moss plants”), have three divisions: mosses, liverworts and hornworts. There are some 18,400 species among the Bryophytes, including about 13,000 mosses, 5,200 liverworts and just 200 hornworts. This group is clearly much smaller in number than the Tracheophytes. The plants also are typically much smaller in size, even in some cases microscopic.

The current issue of Fremontia, the journal of the California Native Plant Society, includes an absorbing article on Bryophytes, and suggests that we should care about them because of their aesthetic charm, contributions to biodiversity, and ecological functions, which include hydrological buffering and nutrient cycling.

Because of such qualities, about two years ago interested persons formed the Bryophyte Chapter of the California Plant Society, to “increase understanding and appreciation of California’s mosses, liverworts, and hornworts—and to protect them where they grow.” For information on this group, visit the website <bryophyte.cnps.org>.

The aesthetic aspect of Bryophytes, moss in particular, might be interesting to gardeners and landscapers.

Moss Garden

Moss Garden, from Moss & Stone Gardens.com

Moss gardening can be a fascinating pursuit for the adventurous gardener with sufficient time and patience. There are moss varieties for many different situations, including both sunny and shady settings as well as a wide range of soil types (except sand). Growing moss for an unusual garden bed or between stepping stones or pavers can take a year or two and consistent irrigation. For information on such projects, search the Internet for “moss gardens” or visit Moss & Stone Gardens.com for the useful paper, “How to Grow Moss.”

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Landscaping with Olive Trees

Ever since I began organizing my garden in the five Mediterranean climate zones, some existing trees and shrubs were not in the correct areas. A particular concern has been a ninety-foot long section designated for plants from the Mediterranean basin area. This section, on the southwest border of the garden, has a long-standing row of Willow Leaf Cotoneasters (C. salicifolius), screening the adjacent property.

This Cotoneaster is a fine shrub that grows vigorously and produces long, looping branches from its base, and reaches about ten feet high. It is drought tolerant and trouble-free and can be controlled annually by cutting up to a third of the larger branches at ground level.

In most respects, these shrubs are desirable elements of the landscape, but they spread over a large area and create a lot of shade. In addition, as natives of western China, they do not relate to the Mediterranean climate zones.

The plan is to replace these shrubs with several olive trees (Olea europaea), which are native to Crete and Syria, originally, and strongly associated with the Mediterranean basin area. They are evergreens, with gray-green leaves and an attractive natural form that is graceful and billowing.

Fruitless Olive

Olea europaea ‘Majestic Beauty’

Olive trees are most often grown for their fruits, which are the source of olive oil, a popular and healthy resource in the kitchen and on the dining table. Olive trees are widely grown commercially in California’s Central Valley. The Santa Cruz Olive Tree Nursery, a wholesale nursery in Watsonville, offers numerous varieties.

Olive trees are also attractive as ornamentals in the landscape. Home gardeners could grow and harvest olives for processing by olive-oil producers, but several dwarfed non-fruiting varieties are available and well suited for home gardens. Non-fruiting varieties are often preferred for landscape uses because fruit drop can stain pavements and generally can be messy.

The fruitless varieties can produce small quantities of fruits. Fruiting can be limited by pruning flowering/fruiting wood and by planting only one variety in the garden (different varieties are needed for cross-pollination).

Fruitless varieties of O. europaea include ‘Bonita’, ‘Little Ollie’, ‘Majestic Beauty’, ‘Montra’, ‘Skylark Dwarf’’, ‘Swan Hill’ and ‘Wilson’s Fruitless’. Some of these varieties grow naturally as multi-branched shrubs but can be pruned when young as single-trunked trees.

Dwarf, non-fruiting varieties could grow to fifteen feet high and ten feet wide, but their size and shape can be controlled through annual winter pruning. Depending on available garden space, a ten-foot high tree might be preferred and would be sufficient for screening.

I will plant perhaps six olive trees in “mini-groves” to avoid a row along the fence line. This plan might require one or more large shrubs to re-establish the screen between my garden and the adjacent garden. For example, the existing landscape in that section already includes a Rockrose (Cistus x aguilari ‘Maculatus’), which is another native of the Mediterranean basin area, and an attractive, evergreen shrub.

This project will require significant work to cut down the Cotoneasters and grind out their roots. The optimal time for planting olive trees is early fall, to allow a young tree time to become established before the coldest time of the year, but in the Monterey Bay area, where cold is a not important consideration, olive could be planted at most times of the year. In any event, there is ample time for these preparations.

This process will have a dramatic impact, opening up the garden. Gardening can involve many small-scale tasks, but an occasional bold stroke can bring excitement and a significant new look to the landscape.

 

Achieving Resilience in the Garden

I have written enthusiastically about the book Planting in a Post-Wild World: Designing Plant Communities for Resilient Landscapes, by Thomas Rainer and Claudia West

To review my two recent columns about this book, visit “Designing Naturalistic Landscapes” and “Resilient Plant Communities.”

Regular readers will recall the “essential messages” of this book, as boldly summarized in this column:

  1. Good planting design results from harmonious relationships of plants to place, plants to people, and plants to other plants.
  2. Combine plants in interlocking layers, as they occur in natural plant communities:
  • structural/framework plants (10-15% of the total)
  • seasonal theme plants (25-40%)
  • ground cover plants (50%)
  • filler plants (5-10%)

I wanted to overhaul my own garden right away along the lines recommended by the authors.

After a very brief period of planning the next steps, I realized that putting these ideas in place would involve a good deal of thought and study. I had already written, resilient plant communities “require planning and knowledge of specific plants to put into practice.”

I was not alone in this assessment. The others who have read the book also praised its ideas and observed that they would not be easy to apply. In fact, several reviewers concluded that Rainer and West were not writing for home gardeners but for professional landscapers, especially those with exceptional knowledge of plants.

Thomas Rainer replied: “The book clearly acknowledges the complexity of creating plantings that function more like a naturally occurring community. But it doesn’t look at this complexity with despair, but instead, attempts to systematically describe how to do this in practical steps.”

He does recommend planting the four layers in four steps and provides practical advice about site preparation, but the missing pieces are lists of plants for each of the layers for each of the archetypical landscapes, along with knowledge of how plants look and grow together.

These are not small matters for home gardeners, for landscapers, and almost all garden designers.

Emulating Nature, it turns out, is not a simple matter. But one should not be discouraged.

The aspiring creator of a resilient plant community has access to very useful books. I previously recommended Designing California Native Gardens: The Plant Community Approach to Artful, Ecological Garden, by Glen Keator and Alrie Middlebrook, and Thomas Rainer recommends Garden Revolution: How Our Landscapes Can Be a Source of Environmental Change, by Larry Weaner and Thomas Christopher (Timber Press, 2016).

Garden Revolution

For the next step, we have Rainer’s tip: “Real design happens in the field. Take time there to get the layout right. Arrange all plants first, then go back and adjust location and spacing.”

I will report overviews of my progress from time to time, without, as they say, “getting into the weeds.”

Resilient Plant Communities

In a recent column, I referred to a book by Thomas Rainer and Claudia West: Planting in a Post-Wild World: Designing Plant Communities for Resilient Landscapes. Rainer and West present landscape design ideas that are worth applying in home gardens, and indeed in all kinds of gardens. Their ideas are intended to result in gardens that are “more robust, more diverse, and more visually harmonious, with less maintenance.”

To review that recent column, visit ongardening.com, click on “Essays 2017” and then “Designing Naturalistic Landscapes.”

The ideas presented in this book ring true to nature and good sense, and require planning and knowledge of specific plants to put into practice.

This column cannot replace reading the authors’ thoughtful review of familiar landscaping practices and groundbreaking recommendations, but w can consider their essential messages.

Rainer and West indicate that good planting design results from harmonious relationships of plants to place, plants to people, and plants to other plants.

The first of these relationships recalls the “right plant in the right place” axiom, which often refers to locating the plant where it will have the soil, exposure, and moisture that it needs to thrive. To these aspects of place the authors recommend locating plants in the grassland, woodland/shrubland, or forest environment that is their natural home. A garden, as a built environment, should look and function like a “distilled version” of one of those archetypical landscapes.

Consideration of the relationship of plants to people addresses the visual appeal of the landscape. The authors state that plant communities need not be limited to a naturalistic style and can exist within any other style. There are too many garden styles to list, but the basic idea is that the gardener can develop any preferred style and still maintain the plant’s relationships to place and other plants.

Rainer and West feature the relationship of plants to other plants and write about the “levels of sociability” of plants. In nature, some plants grow as individuals, or in groups of various sizes, or in large areas. For example, plants that tend to grow separately from other plants would be candidates for containers, and some plants propagate across vast numbers in large fields (see photographs of this year’s superbloom of wildflowers).

The authors recommend combining plants in interlocking layers, as they occur in natural plant communities. This approach allows plants to support each other, form a diverse and lush garden (as distinct from swaths of a single variety), and provide natural mulch that retains moisture and blocks entry of weeds and invasive plants. They categorize plants in four layers:

  • structural/framework plants — trees, shrubs, upright grasses and large leafed perennials that form the visual structure of the planting (10-15% of the total)
  • seasonal theme plants — mid-height plants that dominate the scene when in bloom, and provide supporting companions to the structural plants when not in bloom (25-40%)
  • ground cover plants — low, shade-tolerant plants that cover the soil, control erosion and provide nectar (50%)
  • filler plants — short-lived species, e.g., annuals, that fill gaps and add short seasonal displays (5-10%)

The authors describe this plant community approach collectively as resilient gardening. The benefits include growing healthy plants, minimizing maintenance (always a popular objective), and providing a systematic approach to developing an attractive, full grouping of plants.

I have been vaguely dissatisfied with a garden that separates plants from other plants by mulch. Developing layered plant communities will require reviewing plants already in place, searching for new plants for the needed layers, and allowing time for growth. The authors have not provided tidy “recipes” for plant communities because there are too many possible variations, including personal preferences, to put in a book. Instead, they have left the design process to each interested gardener.

Enjoy your garden, and consider learning about—and developing—resilient plant communities for your garden.

The Garden Conservancy’s Open Days

The garden tour is a favorite activity of many garden societies, gardeners, and some garden owners.

Garden societies use tours to advance their goals to promote gardening and gardeners use them to gain practical ideas and inspiration. Garden owners want to share their success in the joint pursuits of horticulture and landscape design, and perhaps also their accomplishments in garden art and furnishings.

Volunteers are needed to support smooth and effective logistics, and garden tourists pay a small fee for the opportunity to explore the gardens. Such fees raise funds for the sponsoring group and cover expenses, e.g., publicity signage, plant lists, and refreshments.

These events generally are instances of homegrown Americana, but one group, the national non-profit Garden Conservancy, has significantly advanced the art of garden touring. The Conservancy is an organization that shares over 300 outstanding gardens each year through the annual Open Days program, which it describes as America’s only national garden-visiting program. It offers “a wide variety of gardens… representing the incredible range and definition of what a garden can be: expansive estates and small backyard oases, manicured hedges and wild country gardens, plant collections and outdoor art, edible gardens and gardens that support wildlife.“

The Conservancy’s annual directory demonstrates the national scope of the Open Days program. The book lists gardens by date and location—in most continental U.S. states plus Alaska and Hawaii. The directory is an efficient way to invite visits to one’s local gardens

For a given date and location, the directory lists one-day garden visits for a single garden or, as available, two, three or more nearby gardens.

Conservancy Olson-front door

Recently, I volunteered for Open Days, serving as greeter and ticket-taker for a well designed and maintained garden at a Palo Alto residence. The garden was designed about thirty years ago in Colonial Williamsburg style, and currently has an interpretation of the classic white garden theme, that Vita Sackville-West originated in the 1930s at the Sissinghurst Castle Garden, in the Weald of Kent, England. While the formal style of this garden is not my taste, I genuinely enjoyed seeing it and appreciated the gardener’s skill and dedication. Numerous visitors also indicated their pleasure with examining the garden and photographed highlights.

Conservancy Olson - dining

 

This garden was one of a cluster of five gardens on the day’s Open Days tour for the Palo Alto–Atherton area.

 

 

 

The Open Days program has an opportunity in September to broaden your garden visions by visiting a cluster of gardens in the San Jose area. Here are brief descriptions (excerpted from the Directory) of these gardens:

  • Garden of Cevan Forristt: reflects “his sense of the mysterious and playful” and demonstrates his skill in combining diverse symbolic objects—stone urns and animal troughs, deities and chains, giant ceramic vessels and delicate woodcarvings.”
  • Holden Garden: featured in Sunset Magazine (2003), “in the center of this garden a small waterfall cascades into a six-sided koi pond…each area of the garden is filled with interesting details that invite lingering looks.”
  • Woodford Semitropical Garden: “a twenty-year-old garden specializing in rare and unusual tropical and semitropical plants [featuring] rare palms (135 species) and cycads (twenty-five species), bromeliads, cactus and succulents and other companion plants.”

Visiting one or all three of these fascinating gardens could be a very nice day trip from the Monterey Bay area. (It’s really not far away!)

For more information about these gardens, browse to the Conservancy’s Open Days website, click on Open Days Schedule, and then search for “San Jose.”

I addition to sharing outstanding gardens through the Open Days program, The Garden Conservancy’s Preservation Program “assists outstanding gardens with the expertise they need to survive and thrive.” Its inspiration and first preservation project is the Ruth Bancroft Garden in Walnut Creek, California. Today, that garden continues under the management of a non-profit corporation, providing and flourishing as a tribute to its founder as a resource for gardeners with interest in cactus and succulent plants.

The Conservancy welcomes contributions and memberships.

Gardeners can grow, too! Plan your Open Days visit.

Designing Naturalistic Landscapes

Landscape design has been analyzed, discussed, and written about by many people, and from several angles. Most treatments of this subject consider the built landscape as part of built environment, which contrasts with the natural environment. Generally, they describe landscapes as vignettes or vistas that please the beholder’s eye by combining forms or colors from an aesthetic perspective. Aesthetics determine whether a garden is Victorian, Italian, Japanese, modern, white, classical, etc. Often, this approach results in random groupings of favored plants, with the only design principle being “tall plants in back.”

There are more horticultural perspectives for thinking about landscapes. For example, we have the idea of companion planting, in which proximities affect plant vigor. Then, we have generic groupings, as with small or large collections of roses, cacti, irises, or some other plant genus. Another horticultural approach involves grouping plants with similar needs for moisture. Such “hydrozoning” responds to the horticultural needs of plants and incidentally organizes the gardener’s irrigation tasks. A tropical landscape focuses on plants with an exotic look and a continuing thirst (not a good choice in the land of persistent drought).

Moving further into horticultural considerations, we encounter climate-oriented landscaping, with emphasis on plants from the world’s Mediterranean or “summer dry” regions, which of course include the Monterey Bay area. This landscaping approach supports plant development and vigor and eases the gardener’s workload.

The attractive subset of summer-dry landscaping is landscaping with California native plants, which combines the climate-oriented approach with the ecological compatibility of flora and fauna.

The more naturalistic form of landscaping with California native plants is landscaping with California plant communities. There are various ways to define this state’s several plant communities but essentially, the coast, the mountains, and the deserts are different horticultural environments, and therefore support different plants. A very useful book on this topic has been provided by Glen Keator and Alrie Middlebrook: Designing California Native Gardens: The Plant Community Approach to Artful, Ecological Gardens (University of California Press, 2007).

The next level of appreciating the difference between built and natural landscapes can be found in the book by Thomas Rainer and Claudia West: Planting in a Post-Wild World: Designing Plant Communities for Resilient Landscapes (Timber Press, 2015). This book has been called “inspiring,” “masterful,” “groundbreaking,” and a “game-changer.” Reviewers have also praised it for “lyrical, passionate, and persuasive writing” and “lavish” illustrations.

Planting in a Pot-Wild World - coverThe authors deplore the ways in which typical gardening and landscaping practices have ignored the ways in which plants thrive in natural combinations, and present A New Optimism: The Future of Planting Design. They state, “The good news is that it is entirely possible to design plantings that look and function more like they do in the wild: more robust, more diverse, and more visually harmonious, with less maintenance.”

The book (which we have just begun studying) advocates planting in interlocking layers of plants, which reflects the dynamic way plants grow together in nature. There is much to learn about this approach. The authors envision improved plant labels that provide more useful information about how a plant grows and recommend relevant resources as the http://www.cnps.org/cnps/grownative/California Native Plant Society.

Both aesthetic and horticultural approaches to plant selection have significant impacts on the success of gardening and the amount of work involved in maintaining a garden. If your gardening involves mostly keeping plants alive, replacing plants that have died, combating weeds, and wanting the garden to look better, it could be time to give more attention to plant communities.

Pruning Evergreen Shrubs

Let’s consider evergreen shrubs, which differ from deciduous shrubs by continuing in leaf year-round. This is not the same as retaining leaves all year: evergreen shrubs sometimes are described as dropping their leaves year-round, for on-going renewal.

A separate group of evergreens is comprised of coniferous trees and shrubs, which are pruned primarily in late winter or early spring, before the appearance of new growth. It is now generally too late in the year for pruning coniferous evergreens. Exceptions include removing unwanted whole branches of spruces and junipers, which may be done at any time, and trimming yews and arborvitae can be done when they have a second flush of growth in mid-summer.

We will address the pruning of conifers next winter. These plants require minimal pruning, except as needed to control their size and shape. If you have such plants in your landscape, mark your calendar with a reminder to consider pruning needs around next February.

The larger group of evergreen shrubs should be pruned as needed in April or May, i.e., in mid-spring, after any risk of frost has passed and ideally before new growth starts. In the Monterey Bay area’s moderate climate, there is little chance of frost except in inland regions, and new growth might appear early in the spring. If the gardener initiates light pruning after new growth can be seen, the downside is that some of the plant’s energy will have been wasted, but the plant will simply replace the shoots that have been trimmed.

For pruning purposes, evergreen shrubs can be regarded in one of three groups.

  • Early flowering. Examples include Berberis, Camellia, Ceanothus, Daphne, Mahonia, Pieris, Azalea, Rhododendron, and Viburnum. They bloom in winter, spring or early summer. Many shrubs in this group should be pruned only lightly and deadheaded.
  • Late flowering. Examples include Eucryphia (Leatherwood), and laurels (e.g., English Laurel). These plants bloom in summer and late autumn on either old or new growth. They need little pruning.
  • Mid-season flowering. Examples include Calluna (Heather), Erica, Lavandula (Lavender), Santolina, and Thymus (Thyme). These bloom on old growth in spring or early summer, or on new growth in late summer and autumn. Generally, pruning involves removing shoots after flowering to about one inch of the previous year’s growth.
Daphne Bloom

Daphne odora ‘Aureomarginata” in bloom

The pruning strategy for these plants follows these following basic steps;

First, remove any diseased, damaged, or dead branches. They will not heal themselves and could spread disease, so prompt removal benefits the healthy parts of the plant and helps the gardener to evaluate other needs for pruning.

The second step, then, is to remove branches that are crowding other branches, or compromising the desired appearance of the shrub. The pruning objectives might include reducing the overall size of the plant, either to work better within the landscape plan or to clear a walkway.

A common problem arises when an established, healthy plant grows larger than expected or wanted. Such outcomes should not be surprising: information on the mature size of a plant is readily available at the garden center or in a reference book or website. A bit of research during plant selection can save future effort.

Shrubs that have become badly overgrown might need rejuvenation pruning. In such cases, remove one-third to one-half of the branches to ground level, and reduce all other branches by one-third. In the following two years, remove half of the older branches to ground level.

Pruning time also should be used as an opportunity to evaluate the overall health of the plant. If it has sparse or leggy growth, consider the need for greater exposure to sunlight. For example, a nearby tree might have grown to shade a plant that grows best in full sun, or the plant might have been installed originally in partial shade. In such cases, prune the tree that blocks the sun, or move the shrub to a sunnier spot.

Another factor limiting the plant’s growth might be poor soil, which can be treated with fertilization during the growth period, and regular applications of compost. The gardener should avoid planting in soil with minimal nutrient value, e.g., sandy soil or sub-soil (lacking loamy top soil). If this is unavoidable, consider planting in better soil in mounds, raised beds, or containers.

A third factor might be insufficient drainage. Some shrubs thrive in soggy soil, but the large majority need oxygen at their roots, so the surrounding soil must be allowed to dry out between irrigations. This can be a problem that results when plants are placed in low-lying areas, or in moisture-retaining clay soil.

The third step in pruning includes mulching and feeding. These actions minimize weeds around the plant and help the plant to grow.

The final step is to stand back to appreciate a job well done.

Pruning Deciduous Shrubs

Right now is the right time to prune some (not all) shrubs in your garden.

The first group of targets for pruning in April included flowering shrubs that bloom in the spring on old wood. These plants should be pruned soon after their blooms have faded. This practice allows ample time for buds to develop and bloom in the following spring. Pruning long after the blooms have faded will remove buds as they develop, and reduce or eliminate blooming next year.

Fading Lilac Bloom

The accompany photo shows fading blooms of a Common Lilac (Syringa vulgaris ‘White Angel’) in my garden. This is one of the Descanso Hybrids, which were developed in southern California for mild winter regions, like the Monterey Bay area. Unlike the lilacs from my youth in Connecticut, these hybrids bloom without a winter chill. This plant bloomed nicely and produced a fine fragrance, and now needs pruning in preparation for next year’s flowering.

Here are examples of additional plants in this group that grow well in the Monterey Bay area.

  • Flowering Quince Chaenomeles speciosa)
  • Forsythia (F. ovata and other species)
  • Japanese Rose (Kerria japonica)
  • Lily-of-the-Valley Shrub (Pieris japonica)
  • Mock Orange (Philadelphus lewisii and other species)
  • Ninebark (Physocarpus opulifolius and other species)
  • Purple-leaf Sand Cherry (Prunus × cistena)
  • Viburnum (V. tinus ‘Compactum’ and other species)
  • Weigela (W. florida and hybrids)
  • Winter Daphne (D. odora)

You can identify additional plants in this group by direct observation. If you are undecided, look up your plant in Sunset’s Western Garden Book, the American Horticultural Society’s A-Z Encyclopedia of Garden Plants, or a pruning reference book. You can also search for the plant on the Internet, ideally by botanical name.

Some gardeners are reluctant to prune their plants, either because of uncertainty or a fear of damaging the plant. It can be helpful to regard pruning as therapy for the plant, i.e., it helps and does not hurt the plant.

Pruning improves the plant first by removing dead, broken or diseased twigs and branches. Such parts of the plant are not good for the plant, and could be harming it by spreading disease or drawing resources.

Other benefits are beneficial primarily for the gardener. Timely pruning will improve flowering, fruiting, and overall shape. Flowering shrubs growing without the care of gardeners or landscapers will develop a pleasing natural habit entirely on their own. They will also produce enough flowers and fruit to reproduce, and enough roots and branches to ensure healthy growth. With this in mind, always prune for specific objectives. Before picking up the clippers, take the time to stand or sit down to examine the plant and decide what pruning is needed.

There are two main approaches to pruning: cut back the plant more or less evenly, and remove selected stems or branches entirely. These approaches can be combined. In this case of the lilac, cut below each faded blossom, just above a developing bud, and also remove entirely up to one third of the older branches to encourage new branches growing from the base.

Net week, we’ll consider seasonal pruning of evergreen shrubs.

Remember to sharpen your clippers to make your cuts clean and easy.