The plant labelled F. pottsi var. alamosensis we observed
in cultivation are easily tell apart from the similarly named
Ferocactus pottsii alamosanus, may be the name "alamosensis"
is merely a misspelling of "alamosanus",
in spite of this error of orthography
the two plant are really different and both worth of cultivation.
"alamosesis" has few wide ribs which are a dull blue-grey in
colour. The areoles are round big woolly largely spaced with few
but strong creamy-white to pale-brownies spines. The stem is only
partially covered by spines and similar to that of F. pottsii.
"alamosanus" has numerous pale green to green-bluish ribs, the
areole are elongated with thin needle-like spines than cover almost
completely the stem.
They are summer-growing
and pretty easy plants thought slow to start.
They are suited for any rich, well drained soil such us clay,
pumice, lava grit, and only a little peat or leaf-mould. If potted,
repot them preferably in the spring, if their roots become cramped.
Generally, they should be repotted every other year in order to provide
fresh soil. However, this doesn't necessarily mean they'll need larger
containers. Fill about a quarter of the pot with broken crocks, gravel,
etc. to promote good drainage. After repotting, do not water for a week
or more. Water regularly during the aestival growth cycle (this plant
need plenty of water, but do not overwater and let their soil dry out
between waterings), and also needs to be
avoided wetting the body of this plant while it is in sunlight. A wet
cactus in the sun light can cause sun burning which can lead to scares
or even fungal infections and death, keep rather dry in winter. No water
should ever be allowed to stand around the roots. Feed with a high
potassium fertilizer in summer.
Exposure: Outside they need a bright exposure, full sun
or half shade in summer if the location is exceedingly hot or bright,
inside needs bright light, and some direct
sun. It can tolerate moderate shade, and a
plant that has been growing in shade should be slowly hardened off
before placing it in full sun as the plant will be severely scorched if
moved too suddenly from shade into sun.
Frost Tolerance: Light frost protection required for safe
cultivation, but can tolerate sporadic light frost. This plants
need a period of cool rest in winter to produce flowers abundantly.
Diseases and pests: Watch for infestations of
mealybug, scale insects and spider mite.
Plant in good conditions will start to bloom when reach the
diameter of only 15-18 cm.
conspecific taxa, varieties, forms and cultivars of plants belonging to
the Ferocactus pottsii
Taxon has lots of synonyms ( like
many other cacti) whit controversial varieties and subspecies: