Page 25a. Ipomoea macherbii or holubii?

 


Ipomoea macherbii?J G Baker?
The succulent 'MORNING GLORY' member of the CONVOLVULACEAE family.
This plant was purchased as a seedling, many, many years ago under the above name.

In 'SUCCULENTS II The New Illustrated Dictionary' (Sajeva and Costtanzo), Ipomoea holubii with one flower, looks almost identical to my plant.
Gordon Rowley's book 'Caudiciform & Pachycaul Succulents' shows Merremia holubii with a caudex identical to mine however, unfortunately not in flower, but this genus is said to have white or yellow blooms ¶¶. His picture of I. bolubii is difficult to use to make a positive identification of my plant.
5 August 04: I have now come across info. which seems to confirm 90% that it is I. holubii.
¶¶ Errata 2000/02 by Stephen Jankalalski "8.21 Merremia holubii hort. is Ipomoea holubii Baker".

 

 

 

 

 

 

 

 

In the winter (Northern hemisphere) the plant is really dormant and must not be given any water at all. In spring the grass- like leaves will appear then watering can begin. Slowly a little once a week, increasing to twice a week.
Flowers will appear, at first one a day working up to ten a day, each flower opening just after dawn then fading in late afternoon.
Flowering begins in mid June thru to mid July. If a day remains overcast then the furled petals do not open. By mid July the daily numbers reduce to one or two daily.
These two photos were taken at the end of June.
In early Autumn the leaves dry up and watering should be tapered off. By mid September stop watering and let the compost get dry ready for the winter.

CULTIVATION: is difficult using an extremely well drained, high potash compost top dressed with grit to prevent the caudex rotting. Position the plant in an open position avoiding shade and drips.
In the growing season a little water when the roots are almost dry, none in the winter in a dry atmosphere in good light at 5șC minimum.
Re pot every 4/5 years using a high potash, well draining compost with slow release fertiliser.

 

 

 

 

 

PROPAGATION: is difficult from seed; use a heated propagator maintained at 15șC. Sow in early Summer keep the seedlings moist for the first 5/6 months, then transfer the plantlets to a cooler environment at 10șC for the next year. Move them to normal glasshouse conditions when they are 3 years old in the warm part of the year.
This year I am trying to root some of the annual green stems in "4-Indol-3-ylbutyric acid (gel2rooy).

 

 

 

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