Keystone Species

June 2025 Plant Availability

June 2025 Plant Availability

Greetings Watershed,

Happy June!


As we enter the longest days of the year, we here at the nursery are celebrating all that makes our gardens feel a-buzz this time of year.


We’ve admired Western Bumblebees (right) bumbling around our Clarkias, Evening Primrose, and Large-flowered Collomia. Skippers are resting on the leaves of Beach Saltbush, and hoverflies are hovering over Snow White Meadowfoam (below). Our first few Anise Swallowtail butterflies have been on wing, nectaring on Coast Angelica and Water Parsley, and hopefully laying eggs on our Dutchman’s Pipevine.


We’ve also had a wild turkey peruse our offerings, a possum, raccoon, and have discovered a few questionably-placed bird nest attempts (right). Seriously–if anyone has tips for convincing birds that the in-ground plants are more attractive than our on-irrigation plants, we’re open to them!


If you’re looking to invite more wildlife into your garden, we encourage the planting of keystone species! We’ve listed some that are in stock below, as well as some wonderful resources at the end of the newsletter to get you started with learning more about keystone species. Be sure to check out the wonderful signs Here’s a wonderful description of keystones from the National Wildlife Federation:


Keystone plant genera are unique to local food webs within ecoregions. Remove keystone plants and the diversity and abundance of many essential insect species, which 96% of terrestrial birds rely on for food sources, will be diminished. The ecosystem collapses in a similar way that the removal of the “key” stone in ancient Roman arch will trigger its demise. The research of entomologist, Dr. Doug Tallamy, and his team at the University of Delaware have identified 14% of native plants (the keystones) support 90% of butterfly and moth lepidoptera species. The research of horticulturist Jarrod Fowler has shown that 15% to 60% of North American native bee species are pollen specialists who only eat pollen from 40% of native plants.

If you’ve signed up to receive our newsletter, you’ve probably already aware of the benefits of planting native plants–consider a keystone species the “most bang for your buck” in terms of providing ecosystem services.


What defines a keystone plant species?

  • Host plants that feed the young caterpillars of approximately 90% of butterflies and moths (Lepidoptera).
  • Plants that feed specialist bees who only eat pollen from specific plants. Keystone plants for native bees feed both specialist and generalist bees.
  • Species that are native to your area, grown from seed to maintain genetic diversity (and ecosystem resilience) and are straight species (not a cultivar).
  • Fun face – 96% of our terrestrial birds rely on insects supported by keystone plants!

Ceanothus – Wild Lilac

Blueblossom Ceanothus

Ceanothus thyrsiflorus


Available in D-40 pots for $11.45 each!


  • Blueblossom ceanothus is a hardy, large evergreen shrub 15′ to 25′ and is Endemic (limited) to California alone.
  • Blueblossom is an attractive plant with glossy green 2” leaves and a fragrant sky-blue blossom flower show in spring.
  • Attracts insects for food for tanagers, shrikes, and others.
  • Nectar source for hummingbirds and seed for bushtits, finches.
  • Larval food for Spring Azure, Pale Swallowtail, Lorquin’s Admiral.
  • 117 species of butterflies and moths lay eggs on Ceanothus species!

Buckbrush

Ceanothus cuneatus


Available in D-40 pots for $11.45 each!


  • This spreading, evergreen shrub is a perfect choice for that hot, dry location, where nothing else seems to grow
  • It is also super in habitat gardens as the flowers attract birds, pollinators, and butterflies.
  • Ceanothus are easy to care for. They are beautiful, drought tolerant, deer resistant, and water wise.
  • Buckbrush is medium sized and usually reaches to 5 ft. tall and equally as wide. Flowers range from a creamy white to a soft pastel purple.
  • Larval host plant for 9 species of butterflies and moths, likely host for many more!

Quercus – Oaks

Coast Live Oak

Quercus agrifolia


Available in D-40 pots for $11.45 apiece!


  • This stately drought resistant evergreen tree grows from 40 to 100 feet tall and has more wildlife associated with it that any other tree in California! Space 35’0″ apart.
  • Several deep main roots tap groundwater if present to a depth of 36 feet and develops an extensive horizontal root branches and surface-feeding root system. Great for stabilizing a slope.
  • This tree has beautiful gray, fissured bark, and is a good choice for a shade tree. Remember, it is important not to water established oaks in the summer.
  • Several cavity-nesting birds use coast live oak for nesting, and Coast Live Oaks host over 270 species of butterflies & moths!

Valley Oak

Quercus lobata


Available in D-40 pots for $11.45, TP-4 pots for $16.50, and 4-gallon TP for $44.50 apiece!


  • A deciduous tree that grows to 70′. Space 40′ apart. Native to the interior valleys and foothills of California.
  • Grows into the largest of North American oaks. It is also the fastest growing of our California Oaks, it can grow to 20′ in 5 years.
  • Valley oaks are tolerant of weeds or lawn under them. Deer will browse so protect when young.
  • A variety of mammals and birds eat their acorns, including the Acorn Woodpecker, Western Scrub Jay, Yellow-billed Magpie, and California ground squirrel. Likely host to close to 200 species of butterflies and moths.

Salix – Willows

Narrowleaf Willow

Salix exigua


Available in D-16 pots for $2.13 and TP4 for $3.93-11.78 each!


  • A deciduous shrub to tree reaching 4-16′ in height, spreading by basal shoots to form dense clonal colonies.
  • Narrowleaf willow has an upright form with slender greyish green branches, silky silver leaves and small pale yellow catkins in spring.
  • Provides streamside erosion control by trapping sediment and nutrients from surface runoff, and preventing them from entering the aquatic system.
  • It is host to a wide variety of pollinators, including butterflies, moths, and some gall-forming wasps. Some birds, such as the Least Bell’s Vireo and Southwestern Willow Flycatcher, prefer to nest in large, dense willow thickets.

Arroyo Willow

Salix lasiolepis


Available in D-16 pots for $2.13, and TP4 for $3.93 each!


  • Arroyo willow grows to about 10-20′. It is a fast growing deciduous tree. Space 15’0″ apart.
  • Usually a multi-stemmed, thicket forming shrub.
  • Many types of songbirds may build their nests in the crooks of willow branches.
  • Arroyo willow has many uses including stream bank stabilization, rehabilitation of riparian zones, improvement of freshwater fisheries, field windbreak and natural area landscaping on moist sites, wetland creation or enhancement, and soil bioengineering.
  • 224 species of butterflies and moths lay their eggs on Arroyo willows!

Salvia – Sages

White Sage

Salvia apiana


Available in D-40 pots for $11.45 apiece!


  • White sage is a 2′ to 5′ evergreen perennial shrub.
  • It makes a very large white to lavender flower spike (5′) with 100+ 1″ flowers.
  • A great bee plant especially prized for honey production.
  • The flowers emerge in summer, but pucker-back, giving the bees fits because they can’t get in and out very well.
  • Beautiful for mass planting on dry slopes. Likes summer drought & good drainage, full sun, and no extra water.
  • Considered sacred by many Native Americans who use this plant in may ways.
  • 65 species of butterflies and moths lay eggs on this plant, including the stunningly beautiful Wavy Lined Emerald Moth

Cleveland Sage

Salvia clevelandii


Available in D-40 pots for $11.45 apiece!


  • A semi-evergreen rounded shrub that grows 3′ tall and 4′ wide.
  • Cleveland sage provides rich violet blue flowers from spring to summer. On warm days Cleveland’s sage will fill the air with the sweetest scent.
  • Leaves can be used as a substitute for culinary sage.
  • To keep a dense and more attractive plant, cut back in the winter by about a third or more when young – once mature with woody stems, only tip prune. Needs good draining soil if giving supplemental summer water.
  • Host plant to the California Pyrausta and Volupial Pyrausta moth, and likely dozens more!

Eriogonum – Buckwheats

Coast Buckwheat

Eriogonum latifolium


Available in D16 pots for $7.70 and D40 pots for $10.20 each!


  • Coast Buckwheat is a small evergreen sub-shrub, usually on coastal bluffs. It grows quickly to a nice mound about 2′ tall and wide. Space 2-3′ apart.
  • The round clusters of cream-colored flowers bloom April – September, turning rusty pink as they dry. A favorite of butterflies and honeybees!
  • Its form, foliage, and flowers are attractive additions to rock gardens and mixed borders. This also is an excellent plant for erosion control and is tolerant of poor soils.
  • Partners well with seaside daisy, sandhill sagebrush, quail bush, and reedgrass.
  • Host to 56 species of butterflies and moths, including several Metalmarks, the Orange Tortrix, Coastal Green Hairstreak, Dotted Blue, and Buckwheat Borer Moth

Naked Buckwheat

Eriogonum nudum


Available in D-16 pots for $7.70 each!


  • This small, flowering, perennial shrub grows 6″-1′ high with cotton ball-like flowers on taller (up to 3 feet tall) naked stalks in late spring/early summer.
  • Their blooms are pale pink to white, and float like snowflakes above the main foliage.
  • An excellent choice for rock gardens. The basal rosette of flat green leaves gives rise to tall leafless stems topped with rounded clusters of white or pale pink or yellow flowers.
  • Plant needs excellent drainage, is drought and heat tolerant, and full or nearly full sun (even tolerates summer afternoon sun).
  • Host for Metalmark butterfly, Bramble Hairstreak, Square-spotted Blue, and many others.

Red Flowered Buckwheat

Eriogonum grande var. rubescens


Available in D-16 pots for $7.70, and 1-gallon pots for $15.25 apiece!


  • An attractive low sub-shrub that rows in low mounds to approx. 2′ tall x 10″ wide.
  • The buckwheats are very important butterfly plants and one of the pillars of their plant communities, but deer like to browse on them so keep them protected.
  • Red-flowered buckwheat is one of the showiest of the buckwheats. It has pale red or pink flowers that bloom from June-October.
  • Superb in borders and containers; excellent for rock gardens or used liberally as a filler. Suitable companions include saffron buckwheat, purple sage, golden yarrow, seaside daisy, clarkias and dudleyas

St. Catherine’s Lace

Eriogonum giganteum


Available in D-16 containers for $8.95 apiece!


  • St. Catherine’s Lace grows to 4’ tall x 5’ wide with attractive wooly, gray, oval leaves. It is the largest of the Buckwheats.
  • It’s also one of the most popular nectar sources for many butterflies, especially the California Blues & Hairstreaks.
  • The profuse clusters of small white flowers start blooming in April and continue until Fall, when the flowers age to a rusty color.
  • St. Catherine’s Lace requires no summer water once established & tolerates clay, though it thrives best in well-drained soil.
  • Provides nectar and pollen for both bees and butterflies, and is host to 56 species of butterflies and moths!

Helianthus – Sunflowers

Common Sunflower

Helianthus annuus


Available in D-40 containers for $6.71 apiece!


  • Common sunflower is fast-growing annual herb that can grow up to 9 feet tall.
  • Harvest the seeds in late fall or let it self-sow to start a new crop for next year.
  • The large, yellow, sunny flowers rotate to face the sun.
  • Its showy ray petals attract hummingbirds and butterflies, which are rewarded with a high probability of finding nectar in the numerous disc flowers.
  • These sunflowers also attract beneficial insects as a larval host plant, and provides fabulous habitat and a bounty of seeds that provide nutritious food for nesting birds!
  • Host to 60 species of butterflies and moths, including the Ambrosia Plume Moth, Ipsilon Dart, and Bordered Patch!

Serpentine Sunflower

Helianthus bolanderi


Available in D-40 containers for $10.20 apiece!


  • This lovely annual/perennial sunflower grows 3-4 feet tall.
  • It grows easily in average Bay Area soils, loves full sun and will delight you with cheery black centered blooms circled by bright yellow petals.
  • The long sunny flowered topped stems are just right to attract a crazy amount of pollinators. This includes Monarchs that drink the nectar.
  • Make sure to save a few stalks for yourself in a flower arrangement–they’re rather long lasting
  • The flowering period from June- October is one of our longest blooming native annuals and will re-seed to provide you with flowers in years to come.
  • Likely host of 31 species of butterflies and moths.

California Sunflower

Helianthus californicus



Available in D-40 containers for $10.20 each!


  • This herbaceous perennial spreads to 10 ft wide and up to 5 ft tall.
  • The birds and bees love this native sunflower is found along stream banks, meadows, and freshwater-marshes.
  • Its sunflower style yellow blooms are visible from mid spring to early fall; producing dozens of 3-5 in. wide golden daisy like flowers.
  • The best technique for watering, to enhance flower producing, is occasionally flooding the ground.
  • The long straight stems make great cut flowers. Likely host plant to 31 species of butterflies and moths!

Powerhouse Perennials

Dutchman’s Pipe

Aristolochia californica



Available in D-16 containers for $7.70 each!


  • This robust, durable, rhizomatous vine will serve to knit your garden’s shrubs and trees together into loose thickets or attractively cover a trellis or fence with rope-like stems to 12 ft. in length.
  • But it’s most noteworthy feature is its odd, bulbous, 1-1/2 inch flowers that appear in winter and spring, dangling from naked stems, and resembling a fanciful Dutchman’s pipe.
  • Nice as a small-scale groundcover under oaks or with coffeeberry, spicebush, and pink-flowering currant. In California habitat gardens, this vine provides color, and is the larval food source of the pipevine swallowtail butterfly!

Common Aster

Symphyotrichum chilense


Available in D-16 for $3.85-7.70, and 1-gallon containers for $15.25 each!

 

  • This perennial grows to 1-3 ft tall and makes a flower bed come alive in late summer through fall, when planted with California fuchsia and California goldenrod.
  • It spreads by rhizomes, likes moist soil but can also go without summer water, and is common on coastal grasslands and marshes.
  • In the garden, prune plant to the ground after flowering in the fall and it will reappear late winter.
  • A good habitat plant, native moths and butterflies use this plant as a nectar source and birds eat the seeds.

Yarrow 

Achillea millefolium


Available in D-16 containers for $5.78 apiece! 


  • Likely host to 10 species of butterflies and moths, supports bats and birds, attracts insects that eat pest insects, and is of special value to native bees!
  • This Semi-evergreen herbaceous perennial grows 1-3 ft tall and is a perfect choice for growing in a meadow garden.
  • The ferny foliage will stay green all year with some summer water and the white umbels make good cut flowers. Cut back after blooming which takes place from March through June.
  • Yarrow spreads by rhizomes, a characteristic of a good slope stabilizer. Also, Checkerspot butterflies are attracted to this plant.

Narrowleaf Milkweed

Asclepias fascicularis


Available in D-16 containers for $7.70 each!


  • This hardy perennial herb grows to 3′ tall and 1′ wide.
  • Narrow leaf milkweed is the most favored larval Monarch butterfly host in California. 
  • Great for a bird garden and a butterfly garden.
  • Can tolerate clay soils sopping wet in winter and rock hard during the summer drought. Keep eyes out for aphids once plants are in the ground, and be gentle during transplanting–milkweeds have sensitive roots!
  • Antique pink flower clusters abound in the summer.
  • Also host to Queen butterflies, and excellent nectar resources for numerous native bees.

Resources:

And, in case you missed it–we’ll be at the Bay Area Butterfly Festival Sunday, June 1st! Hope to see y’all there (or at the nursery, where we’re open 10-4)!

‘Bee’ Well and Happy Planting from all of us at

The Watershed Nursery Cooperative!

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