Plant of the Month (October) : Shrubby Butterweed (Bush Senecio) – Senecio flaccidus var. douglasii ~ Tk-123456

Very young Shrubby butterweed (Senecio flaccidus var. douglasii)

Mother Nature's Garden of Health

It’s
early fall and - fortunately for the pollinators - some of the fall-blooming
sunflowers are still in full glory. We’ve
already featured several of them. But
one of the more unusual garden species, the Shrubby butterweed, can still be
viewed in our Garden of Health. The
scientific name is pronounced sen-EE-see-oh
FLASS-i-dus DUG-las-ee-eye. This plant goes by many common names
including Douglas’ groundsel, Threadleaf senecio, Threadleaf groundsel, Creek groundsel,
Threadleaf ragwort, Douglas’ ragwort, Douglas' shrubby ragwort and Bush senecio.

The
Senecios, commonly called Ragworts or Groundsels are a mixed bag of plants in
the Sunflower family (Asteraceae). The genus Senecio
is currently under revision, based on increasing DNA evidence. It currently contains over a thousand species
worldwide. Some are succulent; others are drought tolerant, but not
succulent. Some produce chemicals that
are toxic and/or medicinal. And all have
yellow ‘sunflower’ type flowers.

In
California, there are currently 19 native Senecio
species, as well as a number of non-native, invasive species. [1] Of the natives, the vast majority grow in the
Sierra Nevada Range. But six species are
native to Los Angeles County, with three native to western Los Angeles
County. Of the local species, California
butterweed (Senecio californica),
Island senecio (S. lyonii) and
especially Senecio flaccidus are the
most common.

In
fact, Senecio flaccidus has an
interestingly wide geographic range. The
species is native to Southwestern U.S. and Northwestern Mexico, including Baja
California. It currently has three named
varieties. Senecio flaccidus var. flaccidus
is native to the Southwest, including the Four Corners states, TX, OK and KS. Variety monoensis
is native to the drier mountains and desert washes of Southern and Central
California, including the north side of the San Gabriels. And Senecio
flaccidus var. douglasii
(sometimes still known as Senecio douglasii),
which is widespread from the Northern California coast and western Sierra
foothills to the Los Angeles basin and foothills. The southern extent of its range is Northern
Baja CA, Mexico.

In S.
California, Senecio flaccidus var. douglasii usually grows along creeks and
in seasonal stream beds in Foothill Woodland, Coastal Sage Scrub, Chaparral,
Valley Grassland, Creosote Bush Scrub and Pinyon-Juniper Woodland plant
communities. The soil is well-drained and often rocky. Plants often get some summer moisture in the
wilds.

Senecio flaccidus var. douglasii: young plants

Shrubby
butterweed is a short-lived (4-6 years) part-woody sub-shrub that loses its
leaves after blooming (or when drought stressed). It rarely
grows to more than about 2-4 ft. (less than 1.5 m.) tall and wide. It creates additional branches each year, ultimately,
becoming a mounded, rather open, shrub. Our plants, raised from seed, are young and
have only a few branches (photo above).
For a better idea of mature plants, see references 2 and 3, below.

Senecio flaccidus var. douglasii: foliage

Senecio flaccidus var. douglasii has blue-green to medium green foliage. The color becomes almost gray in full sun in
hot locations. The branches are slender
and wand-like. The leaves are deeply divided into narrow, linear lobes, so the
foliage is very open, giving plants a lacey appearance. This is the most open of the native bush
sunflowers we grow. The foliage has
little to no aroma. Ranchers dislike
this plant because the foliage is toxic, particularly for cows and horses. The foliage and
seeds are also toxic for humans and pets if eaten – a consideration
for planting this species.

Senecio flaccidus var. douglasii: flowers at different stages

Shrubby
butterweed is a summer/fall bloomer. It
can bloom off and on, with available water, from June through October (or even
all year long). We tend to think of it
as a September-October bloomer in our gardens.
The flowers are a bright golden yellow, arranged in typical sunflower
heads. Both the ray and the disk flowers
are yellow in this species. Like many
Senecios, the number of ray flowers is relatively few (8-14) and there is
usually space between them (see below).
The flowers are showy and cheery – a welcome sight among the oranges and
browns of the fall buckwheats.

Senecio flaccidus var. douglasii: close-up of flowers

The
flowers attract a wide range of insects including butterflies, native bees and
other pollinators. We’ve also seen Praying mantis and other carnivorous insects
on this plant. The seeds are small and
dry, with a fluffy tail. Seed eating
birds, most notably the finches, eat them in the fall.

Senecio flaccidus var. douglasii: seed heads

Senecio flaccidus var. douglasii: seeds

Senecio flaccidus var. douglasii grows in full sun or afternoon shade. It commonly grows in well-drained soils
(sandy or rocky) but ours is doing fine in clay. This is a very drought tolerant plant, but we
like to give it occasional water, particularly in August and early September, mimicking
the summer monsoons. We suspect it would
do fine with more water than we give it – and likely flower over a longer
season. This plant is tough, but it
needs a little water in summer, at least in the dry areas of western L.A.
County. And it’s easy to grow from seed
(see below). Plant fresh seed in
fall/early winter, keep well-watered – that’s all there is to it.

Senecio flaccidus var. douglasii: seedlings

This
species was occasionally used as a medicinal plant. It is most safely used externally, as a
poultice for achy muscles or for pimples, boils and skin infections. Do not take this plant internally, and use
externally only occasionally. All
parts of the plant can be toxic to the liver, particularly with
prolonged use. For more on the
medical precautions associated with this plant see references 4 and 5, below.

Shrubby
butterweed is little used in conventional gardens, even the water-wise
ones. The toxicity of the foliage is an
issue; and there are alternative, more benign native sunflowers available. But the Senecios have a certain look –
somewhat like a golden Coreopsis – that is just what’s needed in some fall
gardens. The flowers make great cut
flowers and can also be used to make a yellow dye (wash hands after
handling). In short, we like this native Senecio.

For a
gardening information sheet see: http://www.slideshare.net/cvadheim/gardening-sheet-senecio-flaccidus

For more
pictures of this plant see: https://www.slideshare.net/cvadheim/senecio-douglasii-web-show

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

______________________________