Lachenalia question

don journet
Sat, 21 Sep 2002 07:07:46 PDT
Dear Mary Sue,
                        Through the genus Lachenalia there is quite a
considerable range in bulb sizes and in the bulbs propensity to produce
offspring. The L. aloides group have probably become popular due to the ease
with which most of them produce bulbils. They are thus good for commercial
trade allowing a rapid expansion of stock without the fuss of twin scaling or
tissue culture and the unreliability of the results coming from seed produced
plants. Some of my species are very shy at producing offset bulbs or dividing.
Whether they will divide once a certain size is reached I am not sure but they
do usually seem to reproduce well from seed with some producing copious seed.
     I certainly do not find 4 inch pots suitable or perhaps should I say ideal for Lachenalia. I would probably describe Lachenalia as gregarious plants liking to be in groups and certainly the display one achieves is enhanced by semi mass planting. In the Australian climate I find that the amount of soil in a small (4" pot) pot is insufficient to maintain moderate temperatures and moisture levels. If the pots were plunged in some medium such as gravel or course sand etc. the effect of small pot size might be minimised. I usually aim to have enough bulbs to comfortably fill a 6" pot but where numbers are low I will use smaller pots as I believe problems can occur from too greater a volume of unutilised mix in a pot.
     These bulbs can be remarkably tough and I have successfully grown bulbs in rectangular pots designed to fit in a standard tray. The pot are about 3.3" x 3.7" and around 3.4" deep. Packed in a tray they do seem to behave like a solid block maintaining moderate moisture and temperature levels. I stress that I do not consider this an ideal way of growing these bulbs but when only single bulbs of a given provenance are al that is available there is not a great amount of choice in choosing planting recepticals.
     Talking of multiplication by division one species that I have found to
quite definitely divide is L. unicolor. This species will divide when the
parent bulb reaches a certain size and seems to frequently divide into bulbs of approximately equal size numbering from two to a dozen or more.
     Some Lachenalia do grow in areas that become completely inundated with
water at certain times of the year and may survive in a peat based potting mix.

     Virus seems to be quite a problem in the genus particularly as it is not
always immediately visible. Crosby in The Plantsman Vol8(3) 1986 refers to the hyacinth mosaic virus and the ornithogalum mosaic virus. He also writes "I strongly suspect that there are other weaker viruses, showing no clear
symptoms, which are widespread in stock of Lachenalia and other bulbs." He
suggests that seedling bulbs are most vigorous but that the plants loose vigour over a few seasons until they are no better than the standard sort. Crosby suggests that we need to continually replenish stock by growing species from seed but how can we ensure genetic integrity without elaborate cages to stop inter species crossing.

Don Journet

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