Cultivation tips for Nhu's Calochortus seeds

Michael Mace
Wed, 09 Nov 2011 23:12:29 PST
Following up on Nhu's very kind donation of Calochortus seeds, here is a bit
of cultural information on some of them, written by Hugh McDonald for the
old Calochortus Society newsletter.  McDonald gardened in the San Francisco
Bay Area (Hayward and Berkeley) and generally used a mix of 50-50 peat and
sand.  So you may want to tweak his instructions for your own conditions...



San Jose, CA




Species requiring stratification:

C. bruneaunis

C. elegans

C. leichtlinii

C. macrocarpus

C. nuttallii

C. palmeri


C. bruneaunis and C. macrocarpus are especially tricky because they grow in
the desert, so they need both stratification and limited watering in winter.
When growing them in Berkeley, McDonald typically watered weekly until the
leaves were about one inch tall, then reduced watering.


Notes on particular species:


Calochortus bruneaunis.  A cold-winter desert species.  Stratify the seeds.
After they sprout, water once a week until they are an inch high, and then
water once a month.


Calochortus eurycarpus.  Grows in high mountain meadows (4800 feet / 1500m)
in Oregon, in part shade or near low shrubs, among low grasses that help
shade the base.  Precipitation varies from 10 inches to 30 inches per year,
much of it in the form of snow.  Snowmelt probably triggers germination in
the spring.  The species gets some summer rain.  Hardy to -30F (-35C).
Blooms in late spring to early summer; it has a short growing season.
Prefers cold winters and mild summers.  In a cold climate, you could put
seeds outdoors in a large pot with snow on top of it.  In warmer climates,
you'll need to stratify the seeds for 6-10 weeks.


Calochortus macrocarpus.  Grows in full sun among sagebrush in the high
desert.  Can survive very tough conditions including -30F winters and 110F
(43C) summers and less than 15" (38 cm) of rain per year -- but will not
grow in mild conditions.  It wants dry cold: two months at near freezing
temperatures, and not too much moisture.  In a damp winter climate, grow it
in pure sand for extra drainage.  In coastal California, Hugh McDonald grew
it in a mix of 50-50 peat and sand, but under a plastic cover 18" wide and
six feet above the pot.  This deflected direct rainfall off the pot, but
allowed just enough to blow in from the side to keep the bulbs happy.  Cold
stratify the seeds.  After they sprout water once a week until one inch high
and then once every two weeks.  Bulbs need to be chilled dry at the start of
every winter; chill in the fall and then plant in January.


Calochortus nuttallii.  A wide range, growing from Nevada to the Dakotas.
Seeds from the coldest areas may need stratification, but McDonald reported
that it was relatively easy to grow in the San Francisco Bay area.
Tolerates some summer water, but is also OK with summer drought.  McDonald
grew it under the western eaves of his house and watered it once every three
weeks.  In lowland California, seeds germinate best if kept in a cold part
of the yard and gradually acclimated to the sun.


Calochortus palmeri.  Grows in seasonally wet meadows fed by snowmelt
streams, at high altitudes.  There are only about ten known stands, so take
good care of this one.  Although it grows in boggy meadows, in cultivation
it is reportedly easy with standard Calochortus conditions, and needs only
moderate water to thrive.  Germination of seeds may be enhanced by moderate
stratification.  Supposedly does very well in wet moderate climates like the


Calochortus plummerae.  Grows in rocky clay soil with the base partly shaded
but the flower in full sun.  Grows on 10-20 inches of rain a year.  Does not
need chilling.


Calochortus striatus.  McDonald didn't write cultivation tips on this one
(at least not any I could find), but I grew it myself, so I'll comment.
Although it is native to seasonally wet alkali flats in the southern
California desert, this one is surprisingly adaptable in cultivation.  I
tried it in a variety of soils, but found that it was happy in a pot in
either a mix of 50-50 vermiculite and sand, or 50-50 peat and sand.  Both
were supplemented with some complete bulb fertilizer.  It did not require
cold stratification, and grew reliably when watered once a week and (like
most Calochortus) left totally dry in summer.


Calochortus tolmiei.  McDonald had trouble with this one.  He said it likes
a lot of water in winter, plus shade, and the high-altitude varieties need
stratification.  He said they also appear to tolerate some summer water and
winter cold.


Calochortus venustus.  The high-altitude mountain forms may need cold
stratification.  Selection NS 04-82 is probably from the area in the central
Sierra where C. venustus is found in a huge variety of colors, ranging from
white to yellow to orange to red.  Stratify these, and take good care of
them.  It is a pain in the neck to get to that location, and you won't often
see seeds from there in the future.  In the wild, this selection is under
snow every winter and grows in spring, blooming around July 4 and then going
dormant.  Low-altitude selections will bloom about one to two months


Calochortus weedii.  Grows in southern California in areas that are close to
desert, among shrubs that shade the base of the plant.  Hardy to at least
10F (-12C).  Does not need stratification, and is fairly adaptable to
cultivation.  (I've found this to be one of my most reliable Calochorti,
tolerating a lot of neglect.)

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