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There are many forms of succulent senecios. Amongst the most beautiful
is Senecio haworthii known from a few localities in the Little
Karoo. The beautiful silver-white, cylindrical, succulent leaves
are its crowning glory. The plant is considered threatened in its
native habitat.
No one knows exactly when the plant was first discovered but it
made its appearance in ornamental horticulture in 1795. The plant
was originally described by esteemed plantsman-botanist, Adrian
Haworth in 1803 as Cacalia tomentosa, the specific epithet
tomentosa referring to the hairy, fleshy, cylindrical leaves.
The name was later changed to Senecio haworthii in honour
of Haworth.
The
plants attain heights of nearly 250 mm in cultivation, but are likely
to be somewhat smaller in their natural environment. Flowers are
bright yellow to butter yellow. The inflorescence (flower) is terminal,
unbranched and 80-11 mm long.
The plants occur on rocky slopes near mountains in the Little Karoo.
They are able to withstand extreme drought and tolerate a fair degree
of cold (- 6ºC). Heat is not a problem either, the plants can
comfortably tolerate temperatures of (+ 40ºC)
Growing Senecio haworthii
Senecio haworthii hardly ever produces viable seed, thus
propagation by cuttings is the answer. In actual fact it is advisable
to prune the plants back as they become very leggy and unsightly.
Plants are very easy to propagate by asexual means (cuttings). Plump,
healthy tip cuttings are the ideal material to use. The cuttings
can be struck in coarse, sharp, river sand. Take cuttings at the
onset of spring. The plants will root under ideal conditions in
a matter of weeks. S. haworthii is opportunistic and will
survive in a variety of soils, but does best in sandy loams.
Senecio haworthii is an ideal container plant. Use natural
terra cotta (clay) pots to really show this plant off to its full
beauty. It is a water wise plant and can be planted in the garden
or a rockery.
Reference
ROWLEY, G.D. 1994. Succulent Compositae. Strawberry Press, California.
Ian B. Oliver
Karoo Desert National Botanical Garden
August, 2002
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