Re: Yucca question from rec.gardens
The 'decorator' Yucca which is now ubiquitous throughout Europe in
indoor planting schemes and on window sills, is Yucca elephantiphes.
This central American native is less hardy than its tougher cousins
from the south eastern US states such as Y. gloriosa, filamentosa
etc., but in my experience it can certainly take short exposures of
several degrees of frost without suffering damage.
As Yuccas go, it is remarkably shade tolerant, very fast growing and
quickly develops into a tall specimen, invariably with long, lax, deep
glossy green leaves as a result of low light levels. Grown out of
doors in full sun, the leaves are much tougher, to 60 cms. long and 8
cms. broad and are held semi-erect They are also much brighter being
almost apple green with a slightly glaucous tinge. Flowering rarely
takes place indoors unless light levels are extremely high and
usually, the plant needs to be between 2.5 and 3 metres high before
the first spikes are borne. On the plants I've seen in flower, the
raceme is stout, between 0.7 - 1m long overall and densely packed with
large, creamy white flowers shaded almost indiscernibly with green.
Here in South Devon, this species can be considered to be fully hardy
in coastal areas and easily withstands the light, very short lived
frosts we occasionally experience. My own plant was a tiny 'slip'
barely 20 cms. high, with no roots 4 years ago. It is now 2.5 metres
high with a thick trunk that is well over 25 cms. in diameter and
should flower within the next year or so. It is growing in thin,
gravelly soil and receives full sun for much of the day. The parent
which is in a neighbour's front garden, flowered at just over 2.5m.
during 1998. Based upon plants growing out of doors both here and
further north in 'the Midlands' where they have 'proper' winters, I
suspect that frost tolerance is to minus 5C ., provided day
temperatures rise above freezing. Prolonged and continuous freezes
over several days will often cause stem splitting and death, but new
growth should resume from the roots provided they haven't been frozen
solid.
By UK standards, Germany is an extremely cold place in winter and I
would suspect Yucca elephantiphes to fail as a result of prolonged,
sub-zero temperatures. However, I would be delighted to be proven
wrong on this point. The best bet would be to cut the existing plant
back to 1 metre high. Regrowth will occur very quickly and the plant
will be a more manageable size for several years to come. The
'prunings can be used as cuttings and quickly develop into nice
plants. 30cms.sections of bare stem are allowed to dry off for
several days and then inserted into small pots containing a very
gritty compost or even pure sand. Rooting can occur with 4 weeks if
given base heat, but even without this luxury, the vast majority of
cuttings will have rooted and commenced into growth in 3 months.
These can either be 'tested' out of doors, or retained for indoor use
with the parent being planted out in a sheltered, sunny spot. With
spring just around the corner (its already here in S. Devon), now is
the perfect time to start work on the main plant.
Hope that helps.
Dave Poole
