Plant of the Month (April) : Fendler’s meadow-rue – Thalictrum fendleri ~ Tk-123456

Fendler's meadow-rue (Thalictrum fendleri): in Mother Nature's Garden of Health

We
love the California spring, when local perennials complement the
spring-blooming shrubs. In fact, we wish
more gardeners included herbaceous natives in their garden plans. One of the more interesting, Fendler’s meadow-rue,
is blooming right now in Mother Nature’s Garden of Health. The scientific name for this species is
pronounced thal-ICK-trum FEND-ler-eye.

Fendler’s
meadowrue is an herbaceous perennial in the family Ranunculaceae (the Buttercup family). This family, which includes genera like Ranunculus, Delphinium, Clematis, Aquilegia, Anemone, Hellebore and Aconitum,
contains mostly herbaceous perennials and annuals. Many have lovely flowers and are well-known
garden plants. Many also produce
chemicals toxic to humans and animals, some of which are used in small doses as
medicinals.

The
genus Thalictrum includes
plants from temperate regions on every continent except Australia. The Meadow-rues (also called Meadow rues or
Meadowrues) usually grow in damp, shady places.
Species and cultivars are widely used in gardens, both for their leafy
foliage and their interesting flowers.

Four Thalictrum
species are native to California; two (Thalictrum
sparsiflorum and T. fendleri) are
native to S. California. Thalictrum sparsiflorum, the
Sparse-flowered meadow-rue, is endemic the Sierras and the San Bernardino
Mountains. Thalictrum fendleri is more widespread, growing primarily in Yellow
Pine, Red Fir, Lodgepole Pine and Subalpine Forests throughout the state.

Fendler's meadow-rue (Thalictrum fendleri): young plant

The two varieties, Thalictrum fendleri var. fendleri
and Thalictrum fendleri var. polycarpum, both grow in Los Angeles
County. T. fendleri var. fendleri
can still be found in the San Gabriel Mountains, while var. polycarpum grows in both the San
Gabriels and the Santa Monica Mountains.
You may have seen them on hikes, growing on shady slopes or along
streams in riparian woodlands. Variety fendleri, the more widespread variety,
grows throughout the western U.S. from Montana and Wyoming to Texas and
northern Mexico; var. polycarpum can
also be found in Nevada, Oregon, Utah and Baja California, Mexico.

Some taxonomists argue that T. fendleri var. polycarpum
is better considered a separate species (Thalictrum polycarpum) [1, 2].
The specimen in our Garden of Health would then be that species; and
some nurseries sell the plant under this name.
Whichever is correct, T. fendleri var. polycarpum tends to
grow in slightly sunnier, drier locations, in Mixed Evergreen Forest and Oak
Woodland communities.[3] This variety
can further be distinguished by its lack of foliage hairs and pink female
flowers (those of var. fendleri are greenish white).

Fendler's meadow-rue (Thalictrum fendleri): plant

Fendler’s meadow-rue is an herbaceous perennial,
with foliage mostly growing in a mounded clump 1-2 feet (30-60 cm) tall and 1-3
feet wide. The flowering stalks are
taller – 4 or 5 feet (1 meter or more) and have sparse foliage. The entire
plant dies back (to the ground) in the dry days of late summer and fall, emerging
again with the winter rains.

Meadow-rue’s foliage is one of its strong points,
at least from a gardener’s perspective. The foliage is quite similar to that of its
close cousin, the Western columbine (Aquilegia
Formosa; see above). The leaves are medium-green
to blue-green and have long, slender petioles (leaf stems). The leaves are several-times compound, with
rounded, irregularly dissected, terminal leaflets (see below). The foliage is reminiscent of Maidenhair fern
(but larger) or a delicate rendering of the Columbine.

Fendler's meadow-rue (Thalictrum fendleri): foliage

Fendler's meadow-rue (Thalictrum fendleri): young foliage

The young foliage is utterly enchanting to
observe. The young leaves, which are a
bright yellow-green, emerge in spring fully formed but compacted. As the petioles lengthen, the leaves unfurl
to their final size. The petioles often
have a red-purple tinge, adding to the foliage spectacle. Preformed leaves are found
in some plants growing in cold climates. This trait protects delicate leaves
but allows plants to leaf out quickly, once the weather warms up. We wonder whether pre-formed leaves developed
as a similar adaptation in our mountain-growing Meadow-rues.

Fendler's meadow-rue (Thalictrum fendleri): male flowers

Fendler’s meadow-rue is usually dioecious, with male
and female flowers on separate plants.
Plants with some bisexual flowers sometimes also occur in this species. The
flowers of both sexes grow on tall (3-6 feet; 1-2 meters), slender flowering
stalks above the foliage. The only way to tell the plants apart is when they’re
flowering.

Male flowers are the showier (above). Neither male nor female flowers have petals
(they do have small, green-white sepals).
But the male flowers have cascading yellow or purple stamens with prominent
anthers (producing the yellow pollen). The
resulting flower cluster is unique and attractive. When most gardeners describe Thalictrum fendleri’s unusual flowers,
they are thinking of the male flowers.

Fendler's meadow-rue (Thalictrum fendleri): female flowers

Female
flowers (above) also grow in clusters of 10-20 along a flowering stalk. The female flowers are simple affairs, with a
single, immature (green) fruit beneath the styles (female sex organs). Each
fruit contains a single seed – an unusual situation in the plant world. In T.
fendleri var. polycarpum, the styles
are medium to bright pink; in var. fendleri,
they are green-white.

Given
the dangling anthers and simple flowers, it’s not surprising to learn that Thalictrum fendleri is a wind pollinated
species [4]. The Meadow-rues are an
interesting genus, with some members being insect pollinated and others
wind-pollinated.

Why
might separate male and female flowers – and wind pollination – have developed
from the more common bisexual, animal pollinated condition of the Angiosperms
(flowering plants)? Those are questions that
plant biologists are just beginning to seriously tackle. And it’s genera like Thalictrum that can shed light on the genetic and environmental factors
associated with the development of sexual differentiation and wind pollination. For more on this exciting story see
references 5-7, below.

Fendler's meadow-rue (Thalictrum fendleri): with other

shade-loving perennials. Mother Nature's Garden of Health.

Being
a woodland species, Fendler’s meadow-rue prefers part-shade to quite shady conditions. It does well with morning sun or in the
dappled shade under trees. It’s not
particular about soil texture; we’ve grown it in very sandy as well as clay
soils. It has a wide range of acceptable
soil pH (5.0-8.0) and is fine with organic mulches. As a woodland/riparian woodland species, it
can also be grown in soils with higher organic content than many of our local
natives prefer.

Fendler’s
meadow-rue is actually quite drought tolerant, but will remain green well into
summer with occasional to near-regular water.
Dress with a modest amount of organic mulch and plants will remain happy
and disease-free. The only problem we’ve
had in our Garden of Health is wind damage to the delicate flowering
stalks. If you live in a windy area, you
might want to consider a protected part of the garden.

Fendler's meadow-rue (Thalictrum fendleri):

with Heuchera and native strawberries

Introduced
into the horticultural trade by Theodore Payne [8], Fendler’s meadow-rue adds
woodland charm to any shady garden. It
works well with the native ferns and other shade-adapted perennials like
Western columbine, Solanum xanti, Douglas’ iris, wild strawberries and the Heucheras. It’s often used under oaks, Blue elderberry
and other trees. Other gardeners use it in moist places like rain gardens or
shady swales.

This
species makes a number of interesting chemicals, some of which are toxic to humans
and animals. No part of the
plant should be ingested. Native
Californians made an infusion of the leaves that was wiped on the forehead for
headaches. A poultice of the foliage was
applied for sprains. In all areas where
this plant grows, people were aware of its toxicity, and used it only sparingly
– and always externally.

Fendler's meadow-rue (Thalictrum fendleri):

home garden, Redondo Beach CA.

In
summary, Thalictrum fendleri is an
interesting plant in an interesting genus.
While it produces toxic chemicals, so do many plants routinely included
in gardens, including Delphiniums, Angel’s trumpet, Azaleas, Coral trees,
Autumn crocus, Flowering tobacco and Hydrangea. Used with respect, this plant
adds seasonal charm to local gardens. If
you’ve got a shady spot, it might be just the plant you need.