Tropicals & Tender Perennials: Hoya macgillivrayi, F. M. Bailey -In Habitat and Cultivation, 0 by mattadeus

mattadeus wrote:
5. PROBLEMS

• The new bronze growth of Hoya macgillivrayi is very soft, easily damaged and bruised and particularly sensitive are the developing peduncles. If the plant suffers a check such as getting too dry, too cold or too exposed to strong winds, the peduncles will most likely abort even though the leaves may remain quite healthy. During the growing period, it is therefore very important to maintain adequate moisture and temperatures, as well as exercising care in the handling and positioning of the plant, so that the loss of any developing peduncles is minimised

• Burning of the leaves, characterised by brown or white scald marks is caused by continuous strong sunlight coupled with little or no air movement around the plant. Fungal infections are also caused by lack of air movement and high humidity that together allow the spores to settle on the leaf and germinate.

• When the leaves become soft and wilted and the cause does not seem to be overly dry soil, it is most likely that the roots have rotted. Cuttings can be taken from the plant in order to save it while the plant is still in relatively good condition. If left until the leaves have yellowed or dropped, it is much more difficult, if not impossible, to rescue the plant. So quick action is important!

• Although Hoya macgillivrayi experiences occasional night time lows of around 55F during the dry season; these are only for a few hours at a time and keeping the plant continuously at this temperature for days and nights on end will weaken it and risk causing it damage.

• In enclosed places, Hoya macgillivrayi is extremely susceptible to mealy bug. Methylated spirits and water (2 parts water to 1 part methylated spirits) sprayed or dabbed around the leaves, nodes or wherever the infestation is concentrated is the easiest method of control. Failing that a systemic insecticide such as one containing ‘Imidacloprid’ is very effective. Either treatment, however, may need to be repeated until all traces of the pests have gone. Mealy bugs are generally not a problem in the open garden where they are eaten by predators.

• Cuttings attempted from soft, immature stems are unlikely to root and survive. Undesirable too, are those cuttings taken from very old woody stems that lack vigour and take a long time (if at all) to root and grow away.



ACKNOWLEDGEMENTS

To David Liddle, who very kindly provided images of habitat and of the named clones, as well as providing valuable insights on Hoya macgillivrayi; and to Carol Noel who kindly helped with editing.
January 2006

Image is of H. macgillivrayi ‘Massey River Qld.' IML0017