HAVE two yucca plants that are both suffering from some sort of
ailment. The leaves started going brown at the tips, then they started
turning yellow and shrivelling, eventually collapsing. One yucca
produced a slight smell, so I sprayed it with a fungal spray, which
cleared up the smell but the leaves continued to yellow. I thought
they might be suffering from root rot, so I repotted them in a freedraining
mix. The leaves continued to yellow. A lady at my local garden centre
said they were probably suffering from mites. I sprayed with a miticide,
but still the leaves continue to yellow. Do you have any ideas?
blackish-brown damage on the leaf tips in your photo suggests the
problem is more likely one of too much water and/or fertiliser than
mites or fungal disease. As an indoor pot plant, yuccas thrive on
neglect. Allow them to get quite dry between waterings, especially
in winter. And when you do water in winter, only give them a small
amount - don't soak the whole mix.
The rather soft look
of the foliage also implies they need more light. Expose them to
as much sun as possible, even to the point of putting them outside
to sunbathe every now and then, but be careful to acclimatise them
to sun gradually so they don't get sunburned. And don't fertilise
them at all unless they look extremely starved - that is, the whole
leaf has an overall yellow appearance.
If all this sounds too
hard, you could always move them outdoors or plant them in a sunny
well-drained spot in the garden, they grow well outdoors in most
warm northern parts of the country with a minimum of attention.
Gardener, Issue 153, 2004, Page 27
Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.