Calochortus -- TOW

Jane McGary
Sat, 06 Nov 2004 08:48:06 PST
Although I live outside the native range of most Calochortus species, I 
have found most of them unproblematic to grow in large, deep pots plunged 
in sand, in unheated bulb frames. The only one I grow in the open garden is 
C. uniflorus, which is native near this region. The other species found 
near my home is C. subalpinus, but it is difficult to grow because it's 
adapted to long winter dormancy under unthawing snow cover. C. tolmiei is 
also reported to grow in the Coast Range across the valley from where I 
live; it is easy to grow in the frame.

As Diana mentioned, much Calochortus seed germinates readily, especially 
when obtained from Northwest Native Seeds (Ron Ratko). The seed retains its 
viability for some years in dry storage. The only species I have failed to 
obtain germination from is C. macrocarpus, a plant of the northern Great 
Basin and semiarid steppe; others report the same trouble with it. Seeds 
typically germinate in cool, moist conditions, and here that means bringing 
them into a frost-free situation as soon as germination occurs. 
Difficulties ensue, since the seedlings are vulnerable to damping off 
(treated with a fungicide) and to aphids (treated with systemic granular 
insecticide). If the seedlings can be kept growing into summer, some but 
not all of them will form bulbs; in some species a certain proportion fails 
to do this and is lost. Crowding may be the reason -- some plant species 
release substances that kill off conspecific competitors within a certain 
area. This and the damping off have taught me to plant the seeds sparsely 
in large pots.

Many growers prefer to leave the seedling bulbs in the original pots for 2 
years, since the bulbs are very small and some germination may be delayed 
until the second year. If this is done, attention should be paid to 
fertilizing the plants when in growth. Once potted on or planted out, they 
should have a dry dormancy. Even those from "monsoon" rain areas of the 
desert seem able to adapt to "Mediterranean" cycles, in my experience. I 
repot them every other year and grow them in deep clay or plastic mesh 
pots, plunged in sand in full sun. All the species I grow have survived 
temperatures to at least 20 degrees F (minus 7 C).

Following are the species that have matured and flowered under this 
treatment here: Cc. albus, amabilis, amoenus, apiculatus, argillosus, 
barbatus, bruneaunis, catalinae, clavatus, coeruleus, concolor, coxii, 
elegans, eurycarpus, excavatus, greenei, gunnisonii, howellii, invenustus, 
leichtlinii, longebarbatus, luteus, lyallii, monophyllus, nudus, nuttallii, 
obispoensis, palmeri, plummerae, pulchellus, simulans, splendens, superbus, 
syntrophus, tolmiei, umpquaensis, uniflorus, venustus, vestae, weedii. I'm 
also growing some others that have not yet flowered -- it can take 6 or 7 
years from seed.

Many Calochortus species increase by bulbils formed on the stem near or 
just below the surface. These start making root growth about now and 
gradually pull themselves down in the soil as they mature. So when you're 
cleaning up dried stems in summer, be sure not to throw away these little, 
hard bulbils.

Some Calochortus species hybridize readily, particularly the Mariposa 
section to which C. venustus belongs. I have a population of hybrids 
between C. leichtlinii and, I think, C. superbus, for instance. Natural 
hybrid swarms also occur.

The commercially available species include C. venustus in various colors 
(being grown in Holland as cutflowers), C. luteus (offered as 'Golden 
Orb'), C. superbus, C. splendens ('Violet Queen' or some such boring Dutch 
bulb name), and C. uniflorus ('Cupido'). The Dutch method of growing this 
genus is to store the bulbs at controlled temperature and humidity until 
late fall, then plant them out very late so they won't break dormancy when 
the weather is still too cold for them. SInce the fields are essentially 
pure sand, planting can be done after frost.

Pests of mature plants include deer and rabbits, and rodents are known to 
eat the bulbs. I haven't seen any Botrytis on the plants in the frame, but 
for some reason there is little Botrytis there anyway. Bulbs that are in 
moist soil during dormancy are likely to rot.

In the garden, it is best to place Calochortus among plants such as 
clumping grasses and leafy low perennials and shrubs (e.g., Helianthemum) 
that will support their tall, bare stems and give them some winter 
protection. Short species such as C. uniflorus and C. tolmiei are suitable 
for the rock garden. Some of the really tall species with big flowers, such 
as C. plummerae and C. clavatus, are best appreciated if supported with a 
natural stake such as a forked branch. However, C. macrocarpus, the tallest 
of all, has a stout stem -- now if I could only get it growing!

Jane McGary
Northwestern Oregon, USA

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