Why Plant Only Native Milkweeds

Photo: Derell Licht https://www.flickr.com/photos/derelllicht/6102171230

Gordon Pratt, High Country Conservancy

For years I have heard that the perennial Mexican milkweed (Asclepias currassavica) is bad for monarch butterflies, but that seemed to be like an old wives’ tale since no one could explain why. Recently I found out from a friend that a protozoan parasite (Ophryocystis electroscirrha) hangs out in milkweeds (perhaps in the sap) and at high concentrations the protozoan kills monarch caterpillars. This interaction is natural and has probably been going on for some time. It seems that the caterpillars pick up the parasite from eating the infected milkweed leaves.

Those plants with high concentrations of the protozoan are more likely to kill monarch caterpillars or chrysalises. Since the non-native Mexican milkweed is perennial and does not die back like most of our native milkweeds, it builds up high concentrations of the protozoan. So, for this reason native milkweeds have lower concentrations of the deadly protozoan and are less likely to kill monarch caterpillars. It seems that you can reduce the protozoan population in the Mexican milkweed by cutting them back in the fall and not allowing them to store high concentrations of the protozoans over the winter. It is best to plant milkweeds that are native to our area, like narrowleaf milkweed (Asclepias fascicularis).

You can find more information at these websites:

https://monarchjointventure.org

http://www.monarchparasites.org

Conservation News for the Fall

By Frank Landis, Conservation Committee Chair

The next eight months are going to be a bit of a rocky ride for everyone, as the political din of the 2020 election season drowns everything else out. Here’s a round-up of major events from the last two months and what to, erm, look forward to. And more importantly, what to act on.

First off, CNPS has joined Endangered Habitats League, Sierra Club, Center for Biological Diversity, Chaparral Institute, and Preserve Wild Santee in suing to decertify the County’s 3-2 approval of the Otay Ranch Village 14 development, now renamed Adara. We’re specifically partnering with EHL on a suit. Along with Newland Sierra, that makes two cases our society is involved in.

Second: on August 5, the San Diego City Council voted 6-3 to approve The Preserve at Torrey Highlands, a 450,000 square foot office building on the eastern edge of Del Mar Mesa. I and two other CNPSers were there, along with 52 other environmentalist speakers. We are deeply disappointed with the result. Kudos to Councilmembers Gomez, Bry, and Montgomery for voting against it, and brickbats to Ward, Campbell, and Moreno for voting for it. Protect Our Preserves (protectourpreserves.org) spearheaded the fight against The Preserve, and if you want to help them, go to their websiteand donate. I’ve been actively involved helping them. Since The Preserve property didn’t have any listed plant species onit, CNPS won’t litigate. That doesn’t mean the project won’t further trash Del Mar Mesa, which is why I’m personally fighting it, but state CNPS, the organization which actually sues, has fairly strong guidelines for when we do and do not get involved in cases. In any case, Protect Our Preserves needs your help.

Black Mountain Rare Plant Survey

By Tom Oberbauer, Botanist and Past President, CNPS-San Diego

Time was drifting by and the summer of rare plant surveys was getting close to the end. The season for surveys and the project financing were almost past in 2015. Margie Mulligan and I were originally supposed to visit the top of Black Mountain, northeast of Sutherland Reservoir, but other commitments prevented her doing it. So, Jim Rocks was interested and Margie made arrangements for us to contact each other. The result was that Jim was going to be able to drive and I would meet him at his office in the Clairmont/Mission Bay area.

I drove there quite early one morning, arriving by 7:30 am. We loaded into his Honda Ridgeline 4X4 and drove out through Ramona and up Magnolia Avenue and then down into Pamo Valley. The vegetation was not completely toasted because of one interesting July rainstorm, the remnants of a tropical storm. It dropped quite a bit of rain in a number of places in San Diego County including 4 inches in Ramona where it flooded some streets.

The plant that appeared to benefit the most from the July rain was Salsola kali (Russian thistle). It was green and growing profusely in all of the open fields. However, the rain would have also assisted the native chaparral shrubs and oak trees during a very dry time of year. The road climbed gently up into the hills north east of Ramona and then dropped down into an oak and sycamore lined canyon, shaded by the larger trees but providing a view of a narrow valley as it lay before us.

Birdscaping Your Garden Using Native Plants: A Q&A with Teresa Everett

Teresa Everett.jpeg

Teresa Everett, California Native Gardening Specialty Presenter and Featured Gardener on the CNPS-SD Garden Tour 2018, will present “Gardening is for the Birds: Birdscaping Your Garden Using Native Plants” at 9:00am on September 14 at the full-day workshop:

The Resilient California Native Garden


Teresa, why should we plant native plants for birds?

Our California native flora have been coexisting and evolving with our native fauna for tens of thousands of years. Native vegetation provides the right food in the right packaging at the right time for our local birds. The food provided by plants can be in the form of tender flower petals and leaves, seeds, fruit, and nectar. Since these plants have co-evolved with our birds, they provide the most appropriate nutrition and a much greater selection and for the birds in your garden than non-native plants. Native plants are always better than bird feeders as bird feeders tend to be filled with “cheep” seed that is more equivalent to a meal at a fast food restaurant.  Insects and spiders that are attracted to our native plants provide protein for our insectivorous feathered friends. 

Native plants support a much greater array of insects than non-natives. This is particularly true of caterpillars which are a main source of food for baby birds. These foods are packaged for the birds in ways that have evolved to benefit both the plants and the birds. Nectar is stored in tubular flowers for hummingbirds and orioles. Insects can be found under bark for woodpeckers and nuthatches, in leaf galls for insect eating song birds, or simply crawling about snacking on leaves waiting for a hungry bird to snatch it up. Native plant based food can be found throughout the year with the largest quantity and quality available in the spring when breeding birds’ needs are the greatest. By maintaining a native landscape in your yard you can provide a “farm to table” supply chain at it’s best!

Can you give us an example of a relationship between a particular bird and a particular California native plant?

California fuchsia (Epilobium canum) are dependent on hummingbirds for pollination. Epilobium withholds spring blooming to reduce competition for the birds’ attention during the floriferous days of spring. Fuchsia flowers are very narrow and provide a perfect fit for the hummingbirds’ thin bills. Honeybees, carpenter bees and other larger pollinators are too large to fit into the deep flower tubes, leaving the nectar on the table for the hummers. However, as always in nature, there are some cheaters. There are several large pollinating insect species that will actually perch on the base of the floral tubes, pierce the flowers with their mouthparts and steal out the nectar without helping to pollinate the blossom. You can look for tiny holes at the base of your fuchsia blossoms to see evidence of these little sneaks.

Photo: Michael Evans

Do you have a favorite California plant that you enjoy watching its relationship with birds in your garden or elsewhere?

I would have to say that our Coast Live Oaks (Quercus agrifolia) provide the best bird watching opportunities. We have sharp-shinned hawks using our oaks as ambush sites to sweep down on smaller birds in the garden. I particularly enjoy when the acorns are mature and the scrub jays make their boisterous visits to our yard. Their noisy acorn foraging reminds me of my childhood home in the Santa Monica Mountains. A more melodious visitor is the bushtit. Large flocks of bushtits will sweep into our oaks and glean insects and spiders while filling the tree with their constant twittering calls. Some years the bushtits will build their sock-like hanging nests and join the hummingbirds in raising their young in our oaks. Large or small, the live oaks attract them all!

Teresa Everett’s interest in California native plants developed while growing up in the canyons of the Santa Monica Mountains amid black walnut trees, live oaks, grey foxes, and scrub jays. She majored in Ecology, Behavior, and Evolution at UCSD and has worked as a National Park Ranger, a zookeeper at the San Diego Zoo and the Safari Park and in the Horticulture Department at the Park. Teresa spent several years as a sales rep and Native Plant Gardening Specialist at Moosa Creek Nursery. In her spare time, Teresa enjoys hiking, kayaking, photography, knitting, and of course, gardening!

Superbloom 2019

Text and photos by Juergen Schrenk

This year's "superbloom" continued through the end of June in our local mountains. We have never seen the Lagunas this floriferous in late June. The chaparral along Sunrise Highway was in full bloom, dominated by Chamise (Adenostoma fasciculatum) and California Buckwheat (Eriogonum fasciculatum var. polifolium), interspersed with quite a few Weed’s Mariposa Lilies (Calochortus weedii var. weedii), and Shiny-leaf Yerba Santa (Eriodictyon trichocalyx var. trichocalyx) by the roadside. The short Kwaaymii Trail had plenty of the usually less common Golden Bowl Mariposa Lilies (Calochortus concolor), with Mojave Prickly Pear (Opuntia phaeacantha) competing for attention. One of my favorites, Summer Snow (Leptosiphon floribundus ssp. glaber), was at its prime, while Western Choke Cherry (Prunus virginiana var. demissa) was already beyond. The equally short Kwaaymii Point Trail was outright lush, and even the slopes towards the desert were still green. Further up the road, along Lake Cuyamaca, the numbers of Cuyamaca Larkspur (Delphinium hesperium ssp. cuyamacae) were stunning in many places; its blue rivaled by that of Dwarf Brodiaea (Brodiaea terrestris ssp.kernensis). For the way back down to I-8 we chose Viejas Grade with a spectacular display of Cleveland Sage (Salvia clevelandii), lots of Weed Mariposa lilies, and pink added by Canchalagua (Zeltnera venusta) accompanied by Fringed Spineflower (Chorizanthe fimbriata var. fimbriata).

A Few Thoughts on Preparing for Fire Season

By Frank Landis, Chair Conservation Committee

I’m supposed to be working on a fire recovery and preparedness guide for San Diego, but my CNPS energy is going into conservation work for fairly obvious reasons.

That said, the weather has predictably turned hot and dry, and all that lovely vegetation that grew this spring is drying out and becoming flammable. Since Cal Fire is telling everyone to prepare and create an evacuation guide, but not really telling how to do it or what should be in it, I figured I’d put some ideas out.

Note that I *am not* a fire expert, and this is merely an opinion that I offer in the hopes that it might help you figure out how to make your own fire plan. The only reason I suggest it is that the putative experts aren’t being very helpful either.

Native Garden Wins Helix’s 2019 Landscape Contest

Helix Water District has named Matt and Lauren Kirkpatrick of La Mesa as this year’s winner of its WaterSmart Landscape Contest, an annual competition that recognizes outstanding water-wise residential landscapes based on overall attractiveness, design, efficient irrigation and appropriate plant selection and maintenance.

Compared to the Kirkpatricks’ previous lawn, this growing, colorful and entirely native landscape requires very little water and creates a place of inspiration and peace for these outdoor enthusiasts. Over the two-month billing period ending this April, this home used just 13 units of water, which is almost 40 percent less than the average water use of other Helix customers.  One unit is 748 gallons.

The Kirkpatricks purchased the home in 2014 with a front yard full of grass that required frequent watering and mowing just to maintain a modest appearance. In the end, the lawn’s appearance was lackluster and proved to be too costly and time consuming for the couple. Taking advantage of SoCal WaterSmart’s grass removal rebate program, the Kirkpatricks tossed their turf for a landscape that requires less maintenance, less water and offers more beauty.

The Struggle to Save the MSCP

By Frank Landis, Chair Conservation Committee

As is becoming normal for these columns, I’m writing it on a Friday in early May to meet a deadline. Then 4:30 comes around, County Planning sends out their email alert, and things change. Friday at 4:30 is when the County has taken to issuing their new EIRs, their announcements of meetings, and in this case, their announcements of schedule changes. Now I’m writing past deadline again, but this is important.

There were two portentous announcements this month. The first was that Otay Ranch Village 14 development project would be heard by the Board of Supervisors on May 22. This set the clock rolling for CNPS and every group that is planning on opposing it. Then on May 10 came the announcement that, no, it will now be heard on June 26. So now I get an opportunity to talk about the Multiple Species Conservation Program (MSCP) and how Village 14 and other issues threaten to break it.

Hummingbird Plants of the Southwest by Marcy Scott

Click picture to preview book

Click picture to preview book

Book review by Cindy Burrascano, Chair Book Sales

Last year I received a beautiful book Hummingbird Plants of the Southwest by Marcy Scott from the publisher for review. The book contains 5 chapters: “Hummingbirds and Their Flowers - A Short Primer,” “Hummingbirds of the Southwest, Creating a Hummingbird Habitat,” “Gardening with Native Plants - Southwestern Style,” and “Hummingbird Plants of the Southwestern United States and Northern Mexico.” The book is informative and photographs are gorgeous for both the hummingbirds and plant species but my glancing through the plant species made me hesitant to carry the book for CNPSSD. The author is trying to describe plant species over a large territory from California to Texas and Northern Mexico to lower Utah and Colorado. My concern is that people look at the lovely photographs and will choose a species that does not occur in San Diego or Imperial County based on the pretty picture of the plant. The book displays 21 species of penstemon but doesn’t include Penstemon heterophylla (foothill penstemon) or Penstemon spectabilis (showy penstemon), the common species for most of our membership and people likely to buy the book from our CNPS chapter. Salvias in the book include 9 species but the most common ones for our area are lumped together in the text with no photographs. I understand that is due to the extent of the area the author is trying to cover but it makes one work a little harder to make sure they choose local species that support hummingbirds. I don’t like to encourage use of non-local species in gardening.

Back to species - I don’t know about your experience with Salvia clevelandii (Cleveland Sage) but when I had a yard in Chula Vista, the Salvia clevelandii  in my backyard and the Epilobium canum (California Fuchsia) in my front yard were regular draws for hummingbirds. Both bloomed for extensive times given a little supplemental water. Cleveland Sage is a beautiful plant but of highly limited distribution over the range of Southwestern hummingbirds and while it is mentioned, it doesn’t have its own photograph in the book. I put the California Fuchsia in my front parking strip, and once it started blooming I was suddenly seeing hummingbirds regularly in the front yard when I used to only see them in the back by the Salvias. I mostly put the California Fuschia there as they are hardy, require little water, and have lovely blooms for extended time if given a little water. I don’t believe I thought about hummingbirds when I planted but I was pleased to see the species is included in the book with a photograph. I enjoyed creating a water spray that the hummingbirds would dive through when I was watering the yard and they were visiting. The “Creating a Hummingbird Habitat” section of the book discusses water features that are attractive to hummingbirds for your garden.

Marcy Scott recently contacted the chapter about her book. She explained to me that she had originally not planned on including California. She lives in New Mexico along the Rio Grande and operates a nursery specializing in Southwestern native plants, plants for wildlife habitat and other resource efficient landscape plants. The migratory nature of the different hummingbird species made it critical to include the information extending to California. The author is trying to encourage gardeners to help overcome some of the loss of food sources for the birds that occurred with extensive development, especially in the coastal part of the state, through inclusion of nectar plants in their gardens. I had picked up two copies of the book prior to her contact and they sold the same night I put them out for sale at the chapter meeting.

Other pertinent information shared by the author when I mentioned my concerns about carrying a book with such broadly based information was that out of 135 plant species mentioned in the book, 41 (or about 30%) are native to one or both counties included in the chapter, including 14 out of 15 California/Baja California endemics. Ipomopsis tenuifolia is only found in San Diego and Imperial counties. The several penstemons, especially P. centranthifolius and P. labrosus; the Keckiellas; the Diplacus species; Salvia spathacea; the two Ribes; and Monardella macrantha -- all are of tremendous importance to resident and migrating hummingbirds, and the plants depend substantially upon them for pollination.

She didn't start out thinking that she needed to include California plants in the book, but as she delved more deeply into the migratory patterns of our western hummingbird species and the corresponding evolution of flowering plants adapting to those movements, it became apparent what a critical role those plants play in the big picture. Hummingbirds depend heavily upon the plants and they in turn rely significantly on the birds - - and with so many threats that both face these days, she wanted to share the information as widely as possible.

Chapter 2 includes six species of hummingbirds listed as regular in California (Black-chinned, Anna’s, Costa’s, Calliope, Rufous, and Allen’s), two species being occasionally reported (Broad-billed (sporadic over large areas) and Broad-tailed (nesting in the eastern part of the state in single leaf pinyon (Pinus monophyla), California Juniper (Juniperus californica), and Salix species), and very rare reports of Violet-crowned, Magnificent, and Blue-throated being seen. The migratory behavior of species is discussed for these species and the others not occurring in California but in the Southwest and Northern Mexico.

In the plant section, the author includes a photograph and information about the size of plants, the bloom period, water use, cold hardiness and USDA zone as well as a page of discussion about the species. I was thrilled to see her advice for planting Indian warrior (Pedicularis densiflora) in her description of the species. It was also interesting to see that the birds will use plants that are not red colored although the bulk of the species included are red blooming. I knew this from seeing them visit purple blooming penstemons in nature. I was never able to keep a Penstemon spectabilis alive in my garden but we planted one at Black Mountain Open Space Park last year and it bloomed and bloomed, and I saw it visited by hummingbirds. The book has at least eight different plant genera with species that are not red blooming so you don’t have to forgo hummingbirds in your yard if you don’t like red flowers.

After reading more of the book instead of just looking at the pretty pictures of species that don’t naturally occur in San Diego and Imperial County, I decided the chapter should carry the book for sale. My concerns remain about people bringing in species not native to this area because of their beauty, and the hybridization with related species that can occur with plants. Since we carry other gardening books that showcase species notnative to the area it didn’t seem right to leave this one out.Please don’t bring the “beautiful but not native to here” species into your garden when you see the beautiful photographs of the different species. Ms. Scott was correct to impress upon me the migratory nature of most of the hummingbird species and their need to travel through California and feed along the way. Ihadn’t thought about the co-evolution occurring between the species and will need to read the book more thoroughly to see what information it contains about that topic or in the extensive bibliography section. I had to wince when I read her statement about eucalyptus and tree tobacco supporting hummingbird species in Southern California due to their prevalence and the loss of their native nectar sources to development. Perhaps if we can get enough nectar species in our gardens, the hummingbirds won’t need the weedy invasives.

Willowy Mint Population Expansion Project

By Lee Gordon, CNPS-San Diego Garden Committee

This report summarizes progress on a project begun in 2016 to find and implement inexpensive methods to expand populations of San Diego Willowy Mint, Monardella viminea. Willowy Mint is a federally listed endangered species, partly because its natural range and habitat are so limited, and because some of its known populations have been in decline.

The purpose of this project is to study and develop methods, encompassing low cost and minimal labor, to expand existing populations and to establish new populations of willowy mint. Our intent is to maximize the number of mature new plants that survive at least 3 years, while minimizing the expenditure of resources.

I began work in November 2016, planting 5 plants grown in pots. We watered the plants when we first put them into the ground, but they got no water after that. One of these plants still survives.

Al Field has since joined me, and in January 2018, we planted 25 small seedlings, all grown in one small, rectangular container. We backpacked water to three, which survived until 2019. We did this because 2018 was a dry year. One of these three was washed away by high flow in a February, 2019 storm. The remaining two appear to be established now and should survive and grow.

On the basis of what we have learned thus far, we will grow and plant as many small seedlings as we can each year, with the expectation that there will be reasonable survival only in good years.

Figure 1. Willowy Mint sites. We get to the three Spring Canyon sites through Mission Trails Regional Park, and the San Clemente Canyon (MCAS) site through the military base. My home (Appendix) is below the T in "Fairbrook Estates".

Figure 1. Willowy Mint sites. We get to the three Spring Canyon sites through Mission Trails Regional Park, and the San Clemente Canyon (MCAS) site through the military base. My home (Appendix) is below the T in "Fairbrook Estates".

Project sites

Figure 1 shows the locations of four sites, three in Spring Canyon and one in San Clemente Canyon, on San Diego City Property that is accessible through the Miramar Marine Corps Air Station.

The three Spring Canyon sites are on property owned by the Sycamore Landfill (Republic Services). Two of these sites (Spring South, Spring North D) have nearby mature Willowy Mints. Spring North A is about 500’ from Spring North D.

The San Clemente Canyon site is about 200' upstream from a population of a dozen or so mature Willowy Mint plants.

Figure 2. Willowy mint planted in 2017 has survived two years without irrigation. This photo and the next two were taken May 8, 2019.

Figure 2. Willowy mint planted in 2017 has survived two years without irrigation. This photo and the next two were taken May 8, 2019.

Spring Canyon

In December, 2016, I planted five Willowy Mints at Spring South. These plants were grown in 4"x4"x9" pots, and their foliage was 4"-6" high. I watered them enough to get them to the rains, and they were on their own after that. One plant survived and is still alive after two summers (Figure 2). Three desiccated and did not recover. One plant placed in the creek bed was washed away in a torrential flow during heavy rains in winter 2017. The flow was unusually heavy, and it also washed away a mature plant that was a few feet from the seedling that disappeared.

In January 2018, Al and I planted 24 small seedlings and one in a pot. The small seedlings were all grown in one 5"x6"x4" plastic container. When planted, they were an inch or so tall and each had one or two pairs of true leaves. We planted them in 8 groups of 3 each, distributed among the Spring Canyon sites. The potted plant died quickly.

Figure 3. Willowy mint planted in 2018 and irrigated during the dry season.

Figure 3. Willowy mint planted in 2018 and irrigated during the dry season.

Figure 4. Willowy mint planted in 2018 and irrigated during the 2018 dry season.

Figure 4. Willowy mint planted in 2018 and irrigated during the 2018 dry season.

Because 2018 was a dry year, we backpacked water to the small seedlings during the dry season. We watered only the most vigorous plants, and the end result was that three survived to the rainy season at the end of 2018. All three were growing vigorously by February 2019, but one was then washed away during a heavy storm. The remaining two are still growing vigorously (Figures 3 and 4).

We planted no seedlings in Spring Canyon for the 2019 season because none of my Spring Canyon seedlings survived to be planted. Given the great rainy season, this was a missed opportunity.

San Clemente Canyon

In January 2019, we planted 25 small seedlings at San Clemente Creek. As before, each seedling had just a few true leaves. The seedlings were planted on the creek bed, at the side of the creek, and on the adjacent bench.

Figure 5. San Clemente Creek flooded by heavy rain (2/14/2019). All of the Willowy Mints planted at this site were under water at this time.

Figure 5. San Clemente Creek flooded by heavy rain (2/14/2019). All of the Willowy Mints planted at this site were under water at this time.

Figure 6. Willowy Mint planted in late December, 2018 and photographed February 27, 2019. This mint had been under water for about a week.

Figure 6. Willowy Mint planted in late December, 2018 and photographed February 27, 2019. This mint had been under water for about a week.

Figure 7 left. Willowy Mint that survived a month under water. Figure 7 right. Willowy Mint that survived three weeks under water. Photos taken May 17, 2019.

Figure 7 left. Willowy Mint that survived a month under water. Figure 7 right. Willowy Mint that survived three weeks under water. Photos taken May 17, 2019.

The creek was flooded by heavy rains starting in mid February (Figure 5). All of the seedlings were inundated, some for a few days, and others as long as a month. Figure 6 shows one seedling a month after planting. This seedling had been under water for about a week, and it had no signs of harm. Figure 7 shows two seedlings that survived inundation for three or four weeks.

Figure 8. Three seedlings that were under water for a few days or a week. Photos taken May 17, 2019.

Figure 8. Three seedlings that were under water for a few days or a week. Photos taken May 17, 2019.

As of May 17, twelve plants still survived, and most of those have grown several times larger than when they were planted. Figure 8 shows three of the largest, all of which were under water only a few days.

Causes of mortality

The largest cause of mortality was desiccation.

The second cause was inundation of the creek. The creek flooded over its banks during a mid-February storm, and water continued to flow for about a month. Seedlings were under water for durations ranging from around a week to a month. Survival was better for seedlings that were immersed less, but a few survived the long immersion. Some were killed by the immersion, and some were eroded away.

A deer browsed a mature plant and several small seedlings in Spring Canyon. One or two small seedlings succumbed, but others sprouted new leaves and survived. The mature plant has also recovered.

Propagation and planting

Willowy Mint flowers in May, and seeds can be collected in July or August. 2018 was so dry that the plants produced few seeds. We only plant willowy mints at each site grown from seeds collected near the site.

Seeds are relatively easy to germinate and to grow into young plants. However, my propagation results have been mixed, which has limited what we have been able to do. I intend to put more attention to improving propagation prior to next fall.

Our preferred method for planting now is to grow as many plants as possible in containers and to plant them soon after they grow their first true leaves. Our containers are for food storage, with drainage holes punched using a hot metal rod. Teasing seedlings apart for planting leaves most of the seedlings bare root, but that seems not to affect their growth. The time from seed to seedling is about two months, so the process begins in August or September.

This approach has some advantages. It is easy to carry a lot of seedlings in a backpack. Planting seedlings bare root means they immediately establish themselves in their native soil. Planting is quick. We make a small slice in the soil with a putty knife, drop the plants in, then gently push the soil back around the roots. These small holes are less disruptive to the soil than digging in pots. It is not clear to us that potted plants have a better rate of success than these small seedlings.

Looking forward

The plan for the future is to plant as many seedlings as we can as soon as the soil gets wet. It may help to plant seedlings multiple times during the rainy season. Seedlings several months old should have considerable advantages compared with seeds that germinate naturally in the rain.

Once planted, we will not irrigate them. I expect all seedlings to succumb in dry years, but enough to survive wet years to produce satisfactory results overall. Plants that survive one dry season without supplemental irrigation should generally be considered established.

Our big challenge now is to improve our propagation methods.

Appendix - Tests behind my house

Behind my house, there is a habitat that approximates a natural willowy mint habitat. It is a small stream fed by runoff from about 14 houses in the neighborhood above me at the top of a hill. The stream often runs when it rains. The soil is cobbles and sand, and it gets no supplemental irrigation. This site is about 3/4 mile west of the San Clemente Canyon site.

Figure 9. Four year old Willowy Mint behind my house (April 2019). This plant has grown to a diameter of 3.5'.

Figure 9. Four year old Willowy Mint behind my house (April 2019). This plant has grown to a diameter of 3.5'.

I began planting mints at this site four years ago, and eight plants have survived at least three years with no mortality (Figure 9). Every summer, the plants turn crispy brown, and fresh green then leaves appear with the rains.

Figure 10. This Willowy Mint was flattened by stream flow during a January 2017 storm. It recovered and it now extends 2.5' along the stream bed, elongated by the action of the water.

Figure 10. This Willowy Mint was flattened by stream flow during a January 2017 storm. It recovered and it now extends 2.5' along the stream bed, elongated by the action of the water.

An interesting observation is that the plants withstand abuse from running water. Figure 10 shows a plant that was flattened by the stream in 2017. Another plant was completely covered by sand. Within a few weeks, leaves began to appear, pushing up through the sand. Both of these plants are doing well now.

Another observation is that the mints are perfectly capable of procreating, but they are not very good at it in their natural habitat. I have never observed immature seedlings in either the mint's natural habitat or near the small stream behind my house. However, about 30' from this stream, I planted one plant in an organic clay topsoil that I irrigate monthly with 1" of water. The plant is partially shaded by a tree. This plant has at least six offspring.

Photo Gallery: CNPS-San Diego Garden Tour 2019

Photographer: Edmond Piffard

Photographer: Ged Bulat

Photographer: Vincent Bellino

Photographer: Edmond Piffard

Photographer: Judie Lincer

Photographer: Ged Bulat

Photographer: Vincent Bellino

Photographer: Ged Bulat

Photographer: Cindy Hazuka

Photographer: Cindy Hazuka

Photographer: Vincent Bellino

Photographer: Vincent Bellino

Photographer: Cindy Hazuka

Photographer: Vincent Bellino

Photographer: Gjon Hazard

Photographer: Vincent Bellino

Photographer: Vincent Bellino

Photographer: Vincent Bellino

Photographer: Cindy Hazuka

Photographer: Judie Lincer

Photographer: Ged Bulat

Photographer: Gjon Hazard

Photographer: Cindy Hazuka

Photographer: Vincent Bellino