Plant of the Month (November) : California wood mint – Stachys bullata

California wood mint (Stachys bullata) in foreground (pink flowers)
Mother Nature's Backyard garden.

The area around the rain garden in Mother Nature’s Backyard gets a little extra water – about every 2-3 weeks this summer and early fall.  That helps the groundcover plants establish – and keeps the whole area a little greener.  One of the plants that’s blooming right now is the California woodmint, Stachys bullata.  This isn’t its peak season, but the flowers keep our hummingbirds and the few remaining butterflies happy.

California wood mint is a member of the mint family (Lamiaceae), a large family that includes culinary mints and the Salvias.   Plants in this family often have aromatic foliage and are used for cooking and potpourri.  Within the Mint Family, the wood mints (hedge nettles), genus Stachys, make up one of the larger genera.  Stachys species can be found on most continents and many are used in traditional herbal medicine.

The Wood mints are also known by the common name ‘hedge nettles’, a name somewhat descriptive but also quite misleading.   Stachys species likely grow under hedges – the shady, somewhat moist conditions being much to their liking.  But Stachys resemble nettles in appearance only.  The leaf shape and emerging plants are somewhat nettle-like.  But the Stachys are mild mannered; they do not sting like the Stinging nettle (Urtica dioica), a plant from an entirely different plant family.  We suspect that gardeners have been dissuaded by the name ‘Hedge nettle’; we prefer the name ‘Wood mint’ for these delightful plants.

The California wood mint can be found in coastal California from the San Francisco Bay to Orange County.  Locally it still grows in the Santa Monica Mountains and in a few places on the Palos Verdes peninsula.  It most commonly establishes on summer-dry, north-facing slopes or moister canyons in the coastal sage scrub, chaparral, oak woodland or riparian woodland communities, at elevations less than about 4000 ft. 

California wood mint (Stachys bullata) as groundcover.
Home garden,  Redondo Beach CA

 

Like most wood mints, Stachys bullata grows as a groundcover or understory plant (mints are common groundcovers in nature).  At most 2-3 ft tall (including the flower stalks), it spreads via underground stems (rhizomes) to form patches 2 to as much as 6+ feet in diameter.  Given a little summer water, it fills an area with green mint-like foliage – our idea of a perfect groundcover plant.

California wood mint (Stachys bullata) : foliage

 

Unlike many mints, California wood mint is not markedly minty.  In our garden it has but a faint minty smell, with a slight hint of lemon, and only when crushed.  Some have described the aroma as objectionable; we find it rather neutral.    The leaves are medium green, softly fuzzy and oval- to triangular-shaped with scalloped edges.  The foliage is similar in appearance to many garden mints.  

In nature, plants usually die back during the dry season, reemerging again with the winter rains.  In the garden, they also die back – either when watering is tapered off in the fall or if there is a frost.   When plants die back – or just start looking raggedy in the fall – it’s time to cut them back to several inches.

California wood mint (Stachys bullata) - Mother Nature's Backyard.

 

In addition to its use as a groundcover, California wood mint is grown for its flowers.  The wood mints generally have larger and more colorful flowers than the culinary mints.   The flowers of Stachys bullata are arranged around the slender square stems in whorls (clusters of flowers encircle the stem).  This type of inflorescence (flower grouping) is typical for the mint family; you may have noticed it in garden mints.  Other good examples are the Salvias – also in the Mint family – which have a similar inflorescence.  

Umber Skipper butterfly approaches California wood mint flower (Stachys bullata)

 

In Stachys bullata, the flowering stems are taller and more erect than the rest of the foliage.   This is also typical of the Mints; the floral placement insures easy access for their pollinators, the hummingbirds and long-tongued butterflies and bees.  In Mother Nature’s Backyard, the Wood mint attracts butterflies as large as the Tiger Swallowtail, but the smaller Skippers are more routine visitors (see above).  For more on Tiger Swallowtails see: http://mother-natures-backyard.blogspot.com/2014/07/western-tiger-swallowtail-papilio.html

 

Close-up of flowers: California wood mint (Stachys bullata)

 

The flowers themselves are typical mint flowers.  The five petals are fused into two lips, with the lower lip significantly longer than the upper.  Flower color ranges from pale pink to lavender or lavender-red.  The upper lip, which shelters the stamens like a cowl, is a single color; the lower lip has stripes or blotches of darker color over a pale ground (see above).   

The flowers are lovely and long-lasting.  We like them in a spring/summer floral arrangement with ferns, alone or with other pink or purple flowers.

 

Simple flower arrangement with California wood mint (Stachys bullata)

 

California wood mint is easy to grow given the right conditions.  In most of S. California it does like some shade, making it a perfect plant to grow under trees, on the north or east side of walls - even in pots on a shady porch.  It will survive nicely in fairly deep shade, though the flowering may be limited. 

California wood mint is not particular about soil texture; we’ve grown it successfully in soils ranging from very sandy to compacted clay (it actually improves the soil texture in the latter).  And it doesn’t seem too fussy about growing in the slightly alkali soils typical of S. California.

While looking best with a little summer water, Stachys bullata is more drought tolerant than one might imagine.  It tolerates seasonal flooding – in fact may be better for it – and looks lovely with occasional to moderate summer water.  We let ours dry out a bit between waterings, in generally watering every 2-4 weeks (even during the past two years of drought).   We like to taper watering off in the fall, letting the plants die back before winter.

California wood mint requires little in the way of care.  Snip off the dead flower stalks after birds have eaten the seeds.  If the plants die back in fall, prune back to several inches to promote lush spring growth.   We use a thin (1-2 inch) organic mulch (wood chips; redwood bark chips) when getting plants started.  After that we let the plants provide their own leaf litter.   

 

New growth in spring - California wood mint (Stachys bullata)

 

If grown in a pot, give plants a dose of ½ strength fertilizer in spring.   And if the plants exceed their allotted space (see above), just pull up the new stems as they emerge (you’ll have to cut them off).  That’s really about it.

So why should you consider growing Stachys bullata?  Certainly it makes an easy-care groundcover, particularly in shady parts of the garden.  It does great on shady slopes, helping to stabilize the soil.    California wood mint might just solve a shady problem area in your yard.

 

Mixed groundcover featuring California wood mint (Stachys bullata), Hummingbird sage (Salvia spathacea; magenta flowers) and Catalina perfume/Evergreen currant (Ribes viburnifolium).

 

We suggest growing it with other native groundcover plants to create a natural woodsy ground cover.  Yarrow (Achillea millefolia), native strawberries (Fragaria species), Catalina perfume (Ribes viburnifolium), Hummingbird sage (Salvia spathacea), native Honeysuckles (Lonicera species) and even Mugwort (Artemisia douglasiana) combine well with the wood mint. The plants share light and water requirements, making them easy to care for.   A mixed groundcover can be a delight – providing interesting textures, fruits, medicinals and flowers over much of the year.

California wood mint is one of our favorite hummingbird plants.  Along with Hummingbird sage,  it keeps our Allen’s and Anna’s Hummingbirds coming back for more.  If you explain nicely, they may even permit you to sacrifice a few flowers for a bouquet!  For more on Hummingbird sage see: http://mother-natures-backyard.blogspot.com/2014/03/plant-of-month-march-hummingbird-sage.html

 

California wood mint (Stachys bullata) and Yerba Buena (Clinopodium douglasii) under a Kumquat tree. 
Home garden, Redondo Beach, CA

 

California wood mint is also an important medicinal plant.  Its most common use is as a topical (skin) disinfectant.  Leaves/stems are soaked or steeped in hot water to create an infusion; when cool, this can used to clean skin sores, wounds, cuts and boils.  Heated leaves and stems can also be pounded/ground to create a warm poultice applied to boils.

An infusion/tea from Stachys bullata  can be used as a gargle for sore throat; it was also traditionally drunk to treat stomach aches. As with any natural remedy (particularly those taken internally), be sure to start with a small dose; and don’t drink more than 1-2 cups of medicinal Wood mint tea per day.   If a wound, sore throat or stomach ache persists or worsens, be sure to seek qualified medical care.

 

For a gardening information sheet see: http://www.slideshare.net/cvadheim/gardening-sheet-stachys-bullata

 

For more pictures of this plant see:  http://www.slideshare.net/cvadheim/stachys-bullata-web-show

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