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Wednesday, May 11, 2016

Plant of the Month (May): Wooly bluecurls – Trichostema lanatum

Wooly bluecurls (Trichostema lanatum) - Mother Nature's Garden of Health


Many garden plants are surprising us these days, despite the drought and blustery winds.  Even some of the ‘gamble’ plants – species we planted despite their questionable suitability – are doing remarkably well.  One such plant is the Wooly bluecurls (Trichostema lanatum, pronounced tri-KOS-te-ma la-NAY-tum), which is looking lovely in Mother Nature’s Garden of Health.

Wooly bluecurls belongs to the Mint family (Lamiaceae), along with the sages (Salvia species), the Pitchersages (Lepechinia species), the Woodmints (Stachys species) and other mints (Mentha; Monardella; Clinopodium/Satureja). Most Trichostemas are aromatic and have distinctive blue or purple flowers. Trichostema  is limited to N. America; and of the 18 species, 11 occur in California, most of them annual wildflowers.

Several Trichostemas grow in Los Angeles County. The annual Trichostema lanceolatum (Vinegar weed) has been recorded from the Santa Monica Mountains, Catalina Island and the Palos Verdes peninsula.   Trichostema austromontanum (also an annual) grows in the San Gabriel Mountains.  The perennial (sub-shrub) Parish's bluecurls (Trichostema parishii), similar in appearance to Wooly bluecurls, can still be seen in the San Gabriels. 

Wooly bluecurls (Trichostema lanatum) in natural setting.
Rancho Santa Ana Botanic Garden, Claremont CA.
Wooly bluecurls ranges from the Santa Lucia and Gabilan ranges of Monterey and San Benito Counties, to northern Baja California, Mexico, in the south.  In Los Angeles County, it grows on Santa Catalina Island and in the Santa Monica and San Gabriel mountain ranges.  It was formerly common on dry slopes below about 3000-4500' in coastal scrub and chaparral communities.  Some very good Trichostema habitat has been lost to human expansion.  There is evidence that this species once grew at lower elevations – places now covered by cities and suburbs.

The first recorded (written) sighting of Trichostema lanatum was by the Spanish explorer Fray Juan Crespi, in 1769. [1] The type specimen was collected by David Douglas, a noted plant collector in the western U.S.  And the species was named and described in 1835 by George Bentham (1800-1884), eminent English taxonomist and long-time president of the Linnaean Society of London. [2] Trichostema lanatum was introduced into the horticultural trade by Theodore Payne.

Young Wooly bluecurls (Trichostema lanatum)
Wooly bluecurls is an evergreen, perennial sub-shrub, growing 3-5 ft. (1-1.5 m.) tall and 4-6 ft. wide.  The plants resemble the Mediterranean herb Rosemary.  In fact, the common names for Trichostema lanatum include Romero (Spanish name for Rosemary), California rosemary and American wild rosemary.

When young (above), plants have several, fairly upright stems, and an overall vase-like form. The younger branches are a dark purple-red, providing a lovely contrast with the foliage.  As a plant matures, it adds upright stems and becomes more branched; mature plants look more like mature native Salvias, with a mounded form.  As plants age, the woody, older parts of the branches lose their foliage, exposing the flaky, gray-brown bark of mature stems.  

Wooly bluecurls (Trichostema lanatum) - maturing plant
To our eyes, Wooly bluecurls is a lovely plant at all ages.  Unfortunately, it often grows quickly for about 3-5 years, then expires in local gardens.   We’ll discuss the reasons why – and things you can do to insure a healthy life – below.  But know that a mature Trichostema is a welcome sight – a rustic old-timer that adds character and a Mediterranean flair to any garden.

The new spring foliage is bright green; it darkens to a medium to dark green by summer.  The leaves are narrow – even linear – 1 ½ to 3 inches (3.5 to 7.5 cm.) long and about ¼ inch wide.  Leaves are shiny above and hairy-white below; and the leaf margins curl under.  This becomes more pronounced in summer/fall – an adaptation to the dry season. 

Wooly bluecurls (Trichostema lanatum): spring foliage

Wooly bluecurls (Trichostema lanatum): close-up of
 spring foliage
Wooly bluecurls (Trichostema lanatum): summer

The most notable aspect of the foliage is its aroma.  It is truly a fragrance of Old California; a bit of pine, a hint of lavender, a fresh sweet scent that is unique to Wooly bluecurls.   Like many other aromatic plants, Trichostema lanatum has a long history of culinary and medicinal use.

Wooly bluecurls (Trichostema lanatum): mature plant in bloom

Wooly bluecurls (Trichostema lanatum): flowering stalk
The flowers of this plant are nothing short of spectacular!  They grow along spike-like inflorescences at the end of branches and in axils along the stems.  The flowering stalks provide striking vertical interest in a late spring garden.  Mature plants can produce 50 or more purple spikes, beginning in April-May in the lowlands – into summer at higher elevations.   The flowers are long-lived and make wonderful cut flowers.  The spikes and flowers are covered with short, wooly hairs – hence the common name Wooly bluecurls.  The flowering stalks are soft to the touch, an aspect that enchants children of all ages.

The flowers themselves are marvels of Mother Nature’s engineering.  The petals are usually a bright royal blue, but range from white or pink to dark purple.  Some cultivars (see below) have unique floral colors.   As seen in the photo below, the entire flower is covered in short hairs, which may be white, pink or purple.
Wooly bluecurls (Trichostema lanatum): close-up of flowers

The calyx (fused sepals) of a typical flower is magenta, which contrasts nicely with the blue-purple of the petals.  Like many hummingbird flowers – and the mints in general - the petals are fused to form a slender tube. Nectar at the bottom of the tube is accessible only to long-tongued pollinators like hummingbirds, large bees and the long-tongued larger butterflies. 

The five petals are modified into two lips, the upper being deeply lobed (see photo).  The sexual parts are exserted (extend out beyond the floral tube) in dramatic fashion, making the flowers quite showy and distinctive.  This is yet another adaptation to hummingbird pollination: the pollen adheres to the heads and backs of nectaring hummingbirds. Pollen is transferred from flower to flower as a by-product of hummingbird feeding.

The seeds (four wrinkled nutlets per flower) are contained in a dry capsule.  Trichostema lanatum is ‘fire-follower’; seeds require stimulus from chemicals in the smoke of burning Coastal Sage Scrub or Chaparral to germinate. If you want to grow it from seed, you’ll need to smoke-treat the seeds.  Some propagators spread twigs of chaparral shrubs over prepared seed flats, burn the twigs, then water and plant the seeds.  An easier method is to purchase smoke-infused filter paper (sometimes called ‘liquid smoke’) which is available on-line; the filter paper is soaked in water, which is then used to soak the seeds prior to planting. 

You can also try using commercial ‘liquid smoke’ or ‘hickory seasoning’ (the stuff used to give meats a hickory-smoked flavor), which is available in grocery stores.  Look for a simple, natural concoction that lists only smoke and water as ingredients.  Hudson Seeds recommends ‘Wrights’ brand; they dilute the liquid as a 1:9 dilution (1 part ‘liquid smoke’: 9 parts water).  Seeds can then be soaked in the liquid overnight or the solution used to water the seeds in (right after planting). [4]

Wooly bluecurls (Trichostema lanatum) in garden.
Rancho Santa Ana Botanic Garden, Claremont CA
In most gardens, Wooly bluecurls does best in full sun.  If you have a hot, inland location, you might have more success with light shade.  Plants like a well-drained soil with a low nutrient content.  So don’t amend your soil with compost before planting – and resist the urge to fertilize this plant.  This is an easy species to kill with kindness!

The other tricky management aspect involves water – or the lack thereof.  Trichostema lanatum takes about 2 years to establish (at least in our garden).  It needs occasional summer water during those first few years.  Thereafter it really needs to be summer dry.  Plant it with other plants that need little/no summer water: Toyon, Fremontia, the local bush Salvias (Black, Purple and White Sage), California sagebrush, California buckwheat and the penstemons.   Standing water, particularly in the warm season (late spring through fall), will kill this plant.  Even a very wet winter can do it in!

If you have clay soil, try placing Wooly bluecurls atop a low berm to improve drainage.   You might also place it in an area that naturally dries out quickly; perhaps along a pathway, next to a large rock or in an area with excellent air circulation.   Then resist the urge to water in summer.  Don’t worry: this is a born survivor that can take a long dry period, as long as it gets adequate winter water.  Wooly bluecurls needs at least 15 inches of water per year, so supplement winter/spring rains in a droughty winter.

Also refrain from piling organic mulch in deep layers around Trichostema lanatum.  A gravel mulch, no mulch at all (except that produced by the plants), or a thin (1 inch) organic mulch are what’s needed.  Another good idea is to tip prune plants after blooming and seed set (late summer).  This will produce a bushier plant, and is particularly important during the first few years.  Be sure to tip-prune only – leave at least 6 inches of foliage per branch and never cut back into old, bare wood.

That’s really about all the management that’s needed.  Placement and watering are the keys.  Other than that, Wooly bluecurls thrives on neglect.  That being said, this plant is a natural choice for difficult-to-water areas like hillsides.  It does well in an herb garden with Mediterranean herbs.  You can use the dried flowers and foliage to make a tasty tea.  They would also make a nice addition to home-made soaps and lotions.

Wooly bluecurls (Trichostema lanatum) in garden.
Madrona Marsh native plant garden, Torrance CA.
Of course Trichostema lanatum is lovely planted with its natural associates like the native Salvias, wildflowers, cool-season grasses and bulbs.    Place in front of a backdrop of evergreen native shrubs to showcase the flowers and foliage.  Flowering plants are truly spectacular when massed.  Be sure to cut a few flowering stalks to use in May bouquets.   The edible flowers can also be used as a garnish on cakes, desserts, etc.

You may be able to find several cultivars at local native plant nurseries and on-line.  ‘Cuesta Ridge’ has pink-purple flowers, is a bit smaller and tolerates occasional summer water.  ‘Susanna Bixby Bryant’ Trichostema lanatum, which has white flowers, is sometimes available from Rancho Santa Ana Botanic Garden’s Grow Native Nursery.

Wooly bluecurls (Trichostema lanatum) against darker foliage.
Rancho Santa Ana Botanic Garden, Claremont CA.
You might also want to include Wooly bluecurls in a medicinal plants garden.  The blooming stalks are collected, bundled and hung upside-down to dry.  The dried flowers and leaves are stripped off and used to make a tea for stomach upset and menstrual cramps.   A tincture made from fresh flowers/leaves can be used as a linament for bruises (for more on making tinctures see: http://mother-natures-backyard.blogspot.com/2015/10/garden-of-health-making-tincture-for.html).  We've tried this tincture on some nasty bruises; it really does numb the pain and reduce swelling and bruising.  In the past, flowers and leaves were fried in oil to make a salve for pain.  Powdered dried leaves were also inhaled as a snuff in treating coughs.  

Limited modern scientific studies suggest that Trichostema lanatum does indeed have anti-inflammatory effects, at least in the test-tube.  There is current interest in determining the relevant plant chemicals, and testing these for their medicinal properties.  This is yet another example of an old medicinal attracting current interest.  We may someday take cold preparations inspired by wooly bluecurls.

Enchanting Wooly bluecurls (Trichostema lanatum)
In summary, Wooly bluecurls is a remarkably attractive evergreen native shrub.  Its flowers and foliage are striking, and the flowers attract some of our favorite pollinators.  In addition, the plant has both culinary and medicinal uses.  While Trichostema lanatum can be challenging – and short-lived – it is well worth including in your water-wise garden.  This is truly an enchanting plant.  Once seen you’ll be hooked - believe us on that!


For plant information sheets on other native plants see: http://nativeplantscsudh.blogspot.com/p/gallery-of-native-plants_17.html





We welcome your comments (below).  You can also send your questions to: mothernaturesbackyard10@gmail.com



  1. I absolutely love your blog. I am getting all jazzed up to start some native seeds this year. I purchased a bunch of different edible native seeds for my garden and landscape. Thank you for sharing your knowledge and wisdom.

  2. Thanks for this comprehensive post on one of my favorite California plants.