Christmasbush senna is an attractive asset to the
fall butterfly garden.
about the time you least expect it the Christmasbush
erupts into a yellow explosion of bloom with such
staggering beauty it stuns all who see it. After all
this is a color in the spring or summer and surely not
expected from mid-October through November and December.
such is the case for this large shrub known botanically
as Senna bicapsularis. In addition to the official
Christmasbush it also goes by names such as winter
cassia, butterfly cassia and Christmas senna. In our
area the bloom period lasts 6 to 8 weeks or until a
frost causes its retreat. It is considered a zone 9-10
plant and a zone 8 perennial. At the Coastal Georgia
Botanical Gardens in Savannah ours was simply stunning
through December and then the 30-year freeze hit in
January. If I lived in zone 7 and had access to seeds, I
would try it on the protected side of my home or try it
as an annual.
was expected it did die to the ground but has rebounded
robustly and is pushing 8 feet in height. It is native
to South America and has escaped in southern Florida and
some parts of the Caribbean causing it to get
established in disturbed areas. In areas with frost it
will be held in check.
you have ever wondered what plants host the sulphur
butterflies, this is one of the best. They will feed the
orange-barred sulphur, the sleepy sulphur and the
cloudless sulphur. In our garden during this time we
typically have an abundance of sulphurs that seem to be
getting nectar from every plant with a bloom.
senna will tolerate partial shade, but it is a fertile
bed in full sun where it reaches it true potential. It
should go without saying, but please apply a good layer
of mulch after planting. Itís not a high-maintenance
plant at all. A couple of times during the growing
season pinch or prune a little to develop a bushy mound.
In our gardens we are growing it adjacent to one of our
historical pillars in the Mediterranean Garden.
its glorious bloom of shocking yellow it will be in
close proximity to the ultimate companions of Purple on
Purple Mexican Bush sage. In other areas of the garden
they are growing in beds geared toward butterflies and
hummingbirds. Here they tower over Mystic Spires Blue
salvia, Blue Fortune agastache, bog sage and a layer of
brown pods reaching 4 to 6 inches long usually follow
bloom, allowing equally opportunity for everyone to have
their own propagation material. The seed coats are hard
and can be lightly scratched or scarified with
sandpaper, so that water can penetrate for germination.
Some suggest pouring boiling water over seeds that have
been placed in a tea strainer.
senna is still not a staple at every garden center, but
we have been fortunate and found them rather easily. You
can also count on finding some great Internet sources.
If your neighbor has Christmas senna, you should be in
luck. Once you get yours youíll be celebrating this
time next year.