HAVE several clumps of smallish vallota lily bulbs, also known as
cyrtanthus or Scarborough lily, but they never flower.
I have spread them around
the garden hoping a different spot might help, but no luck. As they're
from South Africa, I have been sparing with the fertiliser. They
are in sandy soil, so I don't think drainage is a problem. Can you
give me any tips?
first reaction was that perhaps you've been digging them up and
moving them so often they haven't had a chance to reach flowering
size, but that seems unlikely. I checked with bulb expert Lindsay
Hatch from Joy Plants and he suggests the problem could be bulb
fly larvae which can damage the bulb, weakening it so it doesn't
flower but is still capable of producing small bulbs.
The adult bulb fly lays
eggs at the base of leaves just before the bulbs go dormant or they
crawl into the neck of the bulb after the leaves have died off to
lay their eggs. The maggots eat into the bulb, destroying the tissue
Lindsay suggests digging
up the bulbs each year soon after the foliage has died down and
if you find any holes in them to poke a fine wire in to kill the
grub. Store the bulbs and replant the following season. Alternatively,
if you are sure bulb fly is the culprit, you could apply a soil
insecticide, like Diazinon granules, sprinkled around the bulbs
as the leaves begin to die down.
Lindsay recommends planting
vallotas in a sunny, well-drained spot, with the neck of the bulb
just below or even showing at the surface (which, unfortunately,
leaves it more exposed to bulb flies) and to feed with a high potassium
bulb fertiliser. Other suggestions are to cover the bulbs temporarily
over the dormant months with a mulch of good soil or finely ground
bark immediately after the leaves have died off, or to allow a fine-leafed
groundcover to grow over the bulbs, both of which make it harder
for the adult fly to lay its eggs in the bulb.
Gardener, Issue 197, 2006, Page 28
Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.