Watering Strategies from South Bay Botanic Garden

by Susan Krzywicki

Eddie Munguia, Horticultural Lab Technician South Bay Botanic Garden

Eddie Munguia, Horticultural Lab Technician South Bay Botanic Garden – Photo by Susan Krzywicki

After so much debate about how to water native plant gardens, you’d think it had all been said. Let me add some tips and techniques from Eddie Munguia, who is the Horticultural Lab Technician at the South Bay Botanic Garden, located on the campus of Southwestern College in Chula Vista. Eddie installed a native garden over four years ago and one of the key objectives of the botanic garden is to do just this sort of closely observed research and analysis.

Split Cycle Watering – preventing root zone waterlogging
Last July, after attending a professional workshop, Eddie decided to experiment with split cycling – taking the duration of watering proposed, and dividing it into two segments with a two hour gap in between. For example, instead of running a sprinkler zone for 10 minutes, he runs the zone for 5 minutes, in the early morning hours. This allows for absorption by the soil, while avoiding swamping the plant, which can lead to disease and plant death. Eddie has decided that his clear mandate is to “imitate rainfall” by providing supplemental irrigation that looks more like our natural pattern: gentle, sparse summer rains, not heavy storms. During Santa Anas, he recommends 2 minute spritz to cool the plants off. If the plant is suffering from summer stress, he doesn’t dump a lot of water on it, he just refreshes it.

The garden, which is well over 5,000 square feet, is mostly Diablo clay with native hybrid species originating in San Diego county and the Channel Islands.

A view of South Bay Botanic Garden

A view of South Bay Botanic Garden – Photo by Susan Krzywicki

Results: longer bloom times, good growth
Within two weeks of implementing this strategy in July, everything was flourishing. Coast sunflower (Encelia californica) now blooms two months longer. Bladderpod (Isomeris arborea) now produces flower for him all year round. Showy penstemon (Penstemon spectabilis) is blooming later in the year. Bush poppy (Dendromecon rigida) species doubled in size. The garden stay a little greener into summer. And Eddie even observed a third flowering cycle for San Miguel Island buckwheat (Eriogonum grande rubescens).

Advice: Experiment and adjust
Eddie says, “Don’t be afraid to experiment with your watering cycles. As long as you are not bogging them down, or the root zone is getting drenched, they will do OK.” He says he got lucky on the first try with his split-cycle low-impact changes. So, if you follow his method, note garden changes over at least a month, then adjust again.

Would you consider this for your native garden? Please let us know your thoughts, and, if you try this method, please do keep us up-to-date with your progress and observations.

This article was first published in the San Diego Horticultural Society October 2016 newsletter.

Susan Krzywicki is a native plant landscape designer in San Diego. She has been the first Horticulture Program Director for the California Native Plant Society, as well as chair of the San Diego Surfrider Foundation Ocean Friendly Gardens Committee, and is on the Port of San Diego BCDC for the Chula Vista Bayfront.

Creating a Native Wildflower Meadow

By Greg Rubin

A small portion of a 1.5 acre wildflower meadow created by the author in Fallbrook in 2011. Flowers include Tidy Tips, California poppies, Desert bluebells, Owl’s clover, and Chinese houses. Photo by Greg Rubin.

A small portion of a 1.5 acre wildflower meadow created by the author in Fallbrook in 2011. Flowers include Tidy Tips, California poppies, Desert bluebells, Owl’s clover, and Chinese houses. Photo by Greg Rubin.

Few things evoke magical memories like spring wildflowers. Whether it is a desire to recapture a serendipitous discovery of a color-laden flower field from our past, or simply re-living that scene from the “Wizard of Oz”, nothing stirs our passion for nature like a beautiful field of flowers. California was once celebrated for its annual floral shows; unfortunately, these delightful events are becoming a thing of the past.  The great Kate Sessions lamented that wildflowers were disappearing from San Diego’s foothills by the early 1900s. Even her attempts to include wildflower displays at Balboa Park repeatedly failed. Why?

The answer is that European settlement in California altered our delicate ecology so profoundly that it was lost at all levels. Nothing is quite so fragile as a wildflower meadow. These annuals serve as pioneers that help re-establish ecology should a disturbance wipe out climax shrubs and trees. Being so low in lignin, they disappear after dying, returning all of their nutrients back to the ecology. Additionally, they fill holes not occupied by shrubby plants, and persist in places inhospitable to anything with deep roots, such as in the shallow soils of true native grasslands. What the Europeans brought were non-native weeds: competitive plants unhindered by native bio-controls while putting all of their life energy into reproducing themselves.  These non-native seed banks now reach 10-100,000 dormant seeds per cubic foot! The wildflowers never stood a chance.

Seed was spread to create overlapping drifts of color, which is essential to maintain drama in such a large planting of wildflowers. Photo by Greg Rubin.

Seed was spread to create overlapping drifts of color, which is essential to maintain drama in such a large planting of wildflowers. Photo by Greg Rubin.

Fortunately, knowledge is the best tool, and we have ways to turn back the clock. Eliminating weeds is foremost. It is usually not sufficient to clear a space and drop seed, as Ms. Sessions learned. Instead, the seed bank must be addressed, either through repeated watering and killing of emerged weeds, or the use of chemicals called pre-emergents that kill seed in the soil when watered in. This must be done months in advance of planting. Solarization with clear plastic can also be used, but the effect is usually temporary. After treatment, seeds can be spread and either gently raked in or covered lightly in decomposed granite (this avoids disturbance and deters birds). Wildflower seeds can be purchased at most garden centers and online; however, be sure that the word “NATIVE” is somewhere in the title, and that the species are native to your locale, or you will end up with a mix of weedy introduced flowers, the worst being Alyssum. (ED note: You can check the local appropriateness of your chosen seed mix ingredients by entering your address in CNPS’s Calscape app, available at calscape.org or on CNPS’s homepage.) Common native mixes include California Poppies, Lupines, Goldfields, Desert Bluebells, Gilia, Baby Blue Eyes, Tidy Tips, and Farewell-to-Spring. You can add Owls Clover, Five Spot, and Thistle Sage if available. Keep the plot lightly moist until germination, continue watering twice a week if rainfall is lacking, and CONTROL WEEDS! The outcome will be thrilling!

CNPS Member Greg Rubin is the founder and owner of California’s Own Landscape Design, Inc. (www.calown.com) and a popular speaker. A specialist in the use of native plants in the landscape, he is responsible for over 700 native landscapes in San Diego County and co-authored (with Lucy Warren) two books on native landscaping: The California Native Landscape: the Homeowner’s Design Guide to Restoring its Beauty and Balance and The Drought Defying California Garden: 230 Native Plants for a Lush, Low-water Landscape, both on Timber Press.

“The Good Guys”

by Nancy Bauer

Salvia leucophylla 'Pt. Sal' in Nancy Bauer's garden - Photo by Nancy Bauer

Salvia leucophylla ‘Pt. Sal’ in the garden – Photo by Nancy Bauer

We have so many reasons to love our native plants—their beauty, the way they make gardening so easy and so rewarding, how make themselves so at home in our gardens. They are the plants that are thriving without summer water, the ones I don’t have to maintain, and can just enjoy. And they bring a great deal of pleasure to the birds and insects that are also part of my garden landscape.

I am always amazed at the variety of insects that hover around the buckwheats in my garden (Eriogonum latifolium and E. grande var. rubescens). I’ve seen many tiny native bees, honeybees, and other pollinators, plus at least a half dozen of the smaller butterfly species. Buckwheats are also caterpillar food plants for the Acmon Blue, the Blue Copper, and other butterflies.

One of the most sought after nectar plants in my garden from mid-summer into fall is California aster (A. chilensis ‘Pt. St. George’). It gets barely any water at all, forms a low-growing carpet, and blooms for months with small lavender flowers that feed a host of butterflies, bees, and other pollinators. In early spring, the whorls of flowers on the native salvias—brandegee sage (S. brandegei), black sage (S. mellifera), and purple sage (S. leucophylla ‘Pt. Sal’)—are a welcome sight to native bees that have just emerged, Anna’s hummingbirds, and the early butterflies. They, too, receive no summer water.

Birds forage not only on seeds and fruit, but on the many insects our California natives attract. One outstanding example is coyote bush (Baccharis piluaris), which attracts over 200 insects, which in turn feed many songbirds, bats, and other creatures. White-crowned sparrows, finches, and other seed-eating birds feast on the seeds, though they too supplement their diet with insects when seeds are in short supply. If you don’t have room for the shrubs, the prostrate form B. pilularis ‘Pigeon Point’ makes a neat bright green carpet only one foot high but up to six feet wide. Plant it in full sun or part shade with occasional water if needed.

Honeybee on Asclepias speciosa photo by Harmina Mansur

Honeybee on Asclepias speciosa photo by Harmina Mansur

Our native milkweeds are not only caterpillar food plants for the monarch butterfly and a nectar source, they also provide seeds for small mammals and birds. Ladybird beetles and the larvae of lacewings and other beneficial insects hunt the orange oleander aphids associated with milkweeds. Two species of beetles and two species of true bugs are milkweed specialists.

Douglas Tallamy (author of Bringing Nature Home) discovered in his own garden that many of our native insects “cannot or will not use alien plants.” “So many animals depend partially or entirely on insect protein for food,” he points out, “that a land without insects is a land without most forms of higher life.” Our native plants are not just pretty faces; they, as Tallamy so aptly states, “have the critical role of sustaining, directly or indirectly, all of the animals with which we share our living spaces.”

Nancy Bauer is a wildlife habitat gardener and author of The California Wildlife Habitat Garden (UC Press, 2012) and The Habitat Garden Book: Wildlife Landscaping for the San Francisco Bay Region (2001, 2008). She has been teaching and writing about wildlife habitat gardens for over 10 years.

UC Berkeley’s Jepson Herbarium Joins Forces with CNPS on Calscape

CNPS is excited to announce a strategic partnership with the Jepson Herbarium at UC Berkeley to cooperatively develop Calscape, re-launching the site to showcase its many great resources. Calscape now includes plant profiles for all recognized native California plant species, approximately 7000 in total.  Nearly every plant includes a detailed geographic distribution map, built using algorithms based on over 2 million GPS specimen records from the California Consortia of Herbaria, along with detailed elevation profiles across each of the 36 Jepson geographic subdivisions. The plant maps are integrated into Google maps so that users simply type in any California address, city, or GPS location to find out which plants would grow naturally in that spot.

calscape screenshot

Screenshot of Calscape

At its core, planting a native plant garden is nature restoration work, reducing water use and helping to reestablish ecological habitats. “We’re pleased to be working with CNPS and Calscape to help facilitate nature restoration at the local level. Small changes have the potential to make a big impact on the landscape and can help combat the effects of global climate change and degradation of natural systems. Through this partnership, we have combined powerful sources of information to develop a user-friendly interface that will inspire more Californians to include native plants in their gardens and make it easy to choose and purchase native plants from local nurseries,” said Staci Markos, Assistant Director at UC Berkeley’s Jepson Herbarium. The partnership will be ongoing, which means Calscape will provide up-to-date and scientifically-accurate information on distributions from now on into the future.

Plant recommendations are ordered by landscaping popularity, and cross-referenced against Calscape’s nursery database.  In depth plant profiles include photos, plant descriptions, moisture, sun and soil requirements, and landscaping tips to help people choose which plants they want and how to grow them.

After users identify their plant selections they can create an account and save the customized plant list for future reference as well as locate the nearest native plant nursery by going to the Calscape nursery page. The nursery page maps the locations of nurseries throughout California that offer native plant inventory, many of which have integrated their current availability into the database allowing users to view plant inventory through a Calscape ‘plant list’.  This feature not only aims to help users source nearby native plant material but promotes nurseries that have a shared mission in making native plants widely available and routinely incorporated.

calscape nursery screenshotCNPS and the Jepson Herbarium at UC Berkeley hope to use this resource to help bring native plants back to the developed part of the state, along with the birds, pollinators, and other wildlife that depend on them.  With the ongoing destruction of habitat, the California drought, and the growing impacts of climate change, it has never been more important to choose native plants for our landscapes. Calscape makes choosing the appropriate native plants for any location easier than ever, giving Californian’s the tools to restore nature one garden at a time. Please help us spread the word!

Neonicotinoids in Your Garden

Bees on Arroyo Lupine

Carpenter bee, bumblebee and Arroyo Lupine (Lupinus succulentus). Photo by Debbie Ballentine.

In celebration of National Pollinator Week (June 20th-26th) the Xerces Society, the largest pollinator conservation organization in the world, brings awareness to the dangers of a commonly used class of insecticide known as neonicotinoids, or neonics. One of the many benefits of gardening with natives is their ability to provide food and habitat for pollinators. However, when treated with neonics, the insecticide is expressed systemically to all parts of the plant, thus turning pollinators’ sources of pollen and nectar into a toxic danger. The Xerces Society explains, “As a gardener, you have a unique opportunity to help protect pollinators by avoiding the use of these insecticides, asking your local nursery or garden center if plants have been treated with neonicotinoids, and encouraging your city or park district to use alternatives to neonicotinoids on plants that are visited by bees or are bee-pollinated.” Jennifer Hopwood and Matthew Shepherd of the Xerces Society explore the effects of neonicotinoids in further detail in the article “Neonicotinoids in Your Garden”: Read More.

CNPS makes progress against pathogen threat to native plants

Comparison of healthy and unhealthy sticky monkeyflower, courtesy of Suzanne Rooney-Latham, CDFA.

Comparison of healthy and unhealthy sticky monkeflower, courtesy of Suzanne Rooney-Latham, CDFA

May 31, 2016, marked the one-year anniversary of the CNPS Chapter Council’s decision to form an Ad Hoc Committee on Phytophthoras.  This decision was triggered by a request from the Willis Jepson Chapter for CNPS to enact a policy addressing the threat that Phytophthoras and other harmful plant pathogens pose to California native plants.  Since that time the Ad Hoc Committee has completed almost all the tasks necessary to fulfill the intent of the Chapter Council.  The committee’s hard work and steadfast dedication is owed a debt of gratitude for the contributions they have made in just one year’s time.  Their accomplishments were shared with Chapter Council at the June 2016 meeting, focusing on progress made and opportunities for education and assistance on Phytophthora prevention.  Here are some highlights from the committee’s progress report:

  • We collaborated with the U.C. Cooperative Extension’s Working Group on Phytophthoras in Native Habitats to develop Best Management Practices by nurseries and project sponsors to minimize pathogens in native plant nursery stock used in habitat restoration projects;
  • We developed Best Management Practices for clean nursery practices for use by CNPS Chapter Plant Sale Growers to minimize pathogens in CNPS plant sale stock;
  • We conducted two workshops to educate CNPS Chapter Plant Sale Growers on clean nursery practices; and
  • We drafted a CNPS policy on Preventing Infection and Spread of Harmful Pathogens via Native Plan Nursery and Plant Sale Stock, which the Chapter Council adopted last December.

From this point onward, the Ad Hoc Committee will:

  • Educate CNPS Chapter Plant Sale Growers about harmful plant pathogens through our website;
  • Support CNPS Chapters in implementing Best Management Practices that will minimize pathogens in CNPS plant sale stock by offering site visits or consultations by Committee experts; and
  • Collaborate with other organizations on new developments, outreach, research, programs and legislation that support the CNPS plant pathogen policy.

If you want to learn more about how Phythophthoras are affecting native plants you can attend a free symposium session sponsored by the University of California on June 23 at Fort Mason Center in San Francisco (free but registration is required).

If your CNPS Chapter needs assistance to implement Best Management Practices in your nursery, contact Steven Goetz at sgoet@sbcglobal.net.

Landscaping for Southern California Gardens

Summer-dry, drought tolerant, naturalistic, Mediterranean garden with California native Acer circinatum (Vine Maple). Photo by Saxon Holt.

Summer-dry, drought tolerant, naturalistic, Mediterranean garden with California native Acer circinatum (Vine Maple). Photo by Saxon Holt.

By CNPS and Modernize

The unique environment of Southern California, while often a source of great appeal for its residents, poses distinctive challenges for anyone wishing to develop and maintain the aesthetics of their yard. The dry climate, paired with an increasingly limited water supply, means a lush green space is no longer ecologically viable. However, there are many other possibilities for creating a beautiful outdoor space.   The folks at Modernize, a website devoted to home remodeling inspirations, like to view this landscape challenge as an opportunity to create a uniquely Californian place for outdoor living.  Here, they share two approaches to this challenge- xeriscaping and hardscaping- including along the way some of their favorite California native plants for the garden. Continue reading