Extracts from
the ABA Forum
The following is taken from a discussion on the effects of setting
seed on bulbs:
Thank you for your message, interesting point you made, i.e. if under stress seed might be set...What happens if it decides to set seed and then conditions change for the better? Do you know of any controlled experiments that have been undertaken to determine if any changes do or do not take place if flowers are removed, or if seed set or not set, or how much larger bulbs become if flowers are removed or not removed? I am certain we have all read about this, saving the strength of the bulb etc., but have there been controlled tests to prove this?
Dutch
bulb growers regularly remove flowers from their bulb crops grown for sale as
dormant bulbs.
John C. Mather writing in " The
Commercial Production of Tulips and Daffodils" states: - Commercial
experience over many years and the results of repeated experimental work have
shown the importance of heading - that is , removing the flower heads -
especially of stocks required for bulb production. Inflorescence removal
is also appropriate with some short lived perennials in their first year as
they otherwise behave as annuals and die after flowering.
Thanks
for your comments on conducting experiments to find out the effect of seed set
on bulbs. The information gained from such an experiment would, without a
doubt; help to ascertain exactly what is going on inside a bulb, over it's
various stages of a life cycle.
Some genera may not fit into this schematic as well, as say Lilium
or Tulips and Daffodils. These particular plants are selected for their vigor,
disease resistance, production capability, etc., and as such, may not show up
any minor discrepancies that other, less horticultural desirable species could.
Take Moraea for example. This genus is renowned for some of it's species
staying dormant for a period of time, more than a season. This means that some
year they just do not come up. Why is this so? Is this accentuated by the
plants setting seed, or is it more of a result of edaphic and cultural
conditions, or is this just what they do to stay alive over the Millennium. An
experiment with all these factors in tow would yield some interesting results
to throw on the pile of "Knowledge", along with all the other pieces
of information we manage to correlate over the time.
We, as ABA members, could collect this information from plants
that we grow ourselves. We could conduct our own experiments and tabulate the
results for future gardeners/hort-heads to access, and take with them into the
next experiment. I know it will take years to find any results, and even more
years to conclusively say what is going on, but I'm sure this will help. With
such a diverse range of genera that we grow, we may find out even more than we
bargained for.
The following are some links to web
sites for Aussie plants:
Hello again Alex,
here are some web sites that you might like to start with. The Australian
National Botanic Gardens has a large site at http://www.anbg.gov.au/,
which has much information about Australia's flora and also several links
to other useful sites. One of these is the Society for Growing Australian
Plants, also called the Australian Plants Society. This society consists
of gardeners throughout Australia who cultivate native flora. http://farrer.riv.csu.edu.au/ASGAP/ There
are links to seed suppliers here.
In central Australia there
are two botanic gardens at Alice Springs. The Desert Park is
government-operated http://www.alicespringsdesertpark.com.au and the Olive
Pink Botanic Garden is privately run http://www.gardens@opbg.com.au>. In
South Australia there is the Arid Lands Botanic Garden at Port Augusta http://www.australian-aridlands-botanic-garden.org/
I am sure that there are
members of this forum who will be able to help you with your questions about
the Australian bulb flora. Other members will have their favourite sources of
information.
Interesting to hear how
you grow these Haemanthus. A few more points of interest: H. montanus (from all
over the summer rainfall areas of SA), in the most south-easterly part of its
habitat, which is near us, is found in small areas of poorly drained shallow
soil over rock slabs. They grow in dense stands, the large cream flowers
appearing in midsummer, rapidly followed by two or three upright leaves. The
seeds ripen in February and germinate within a month around the parent plants.
The
leaves dry off and blow away by the end of May when all signs of the bulb
population then vanish - the necks are just below the soil. Cattle graze there,
and often trample the bulbs, but they keep going! They have a long dormancy
from late autumn to midsummer. We grow them outdoors in raised (15 cm) beds,
where they get plenty of spring rain, but stay dormant until January! So Jim,
it seems a tricky business to get them to change their growing cycle.
H. humilis humilis
(H. humilis hirsutus is further north, as you said) has fairly round flat leaves
and occurs in isolated colonies on steep slopes between protective rocks. It is
extremely variable with regard to size, the degree of hairiness and the colour
of leaves and flowers. A colony in the Kei River valley growing under acacia
trees in semi shade, has small gray hairy leaves and cream flowers, while
another colony, growing in full shade on a south facing cliff less than 10km
away, has massive dark green leaves up to 50cm in diameter, almost hairless,
and gorgeous large deep pink flowers.
A
leaf that we put in a plant press surprised us after a month or two with a few
(flattish!) bulbils that developed in the press, having some space created by
the thickness of the leaf. Another particularly dark pink form occurs in the
Central Karoo in a region with a rainfall of less than 300mm per annum and
night temperatures that can drop to -10°C in the winter - growing under the
shelter of rocks which seemed to also provide some moisture (near New Bethesda
between Graaff Reinet and Middleburg).
The H. carneus are on
a mountain slope, grasslands with rocky soil, annual rainfall about 600 mm,
mainly in summer. They grow from (late) midsummer to late spring. H. carneus is
very closely related to H. humilis, the main difference being stamens included
well within the perianth. They do seem to need more moisture, even just a
sprinkling, to stay plump. There was an article in Veld & Flora a while ago
about Massonia leaves (also flattish on the ground) utilizing the dew as a
source of moisture, absorbing it through the leaves. Perhaps the flat-leafed
Haemanthus have the same activity! So they get 'watered' throughout the year.
Rhoda
Stutterheim
E.
Cape