Nerine matters
Hamish Sloan (Fri, 16 May 2003 04:21:37 PDT)

Diane wrote:
"It is early summer here in the Northern Hemisphere. Every day the
leaves of my indoor sarniensis hybrid nerines look more bedraggled.
Some are still green, but drooping down the outside of their pots.
They are starting to dry. Two, however, have leaves lushly green and
standing bolt upright. I've just checked the labels and they are
both Eos, that I bought last fall (autumn). They are right in the
middle of my small collection, and have not been treated differently
to the rest.

Does Eos remain green year round? Or will it die down later in the
summer?"

It may die down or it may be one that is evergreen. A clue will lie in when
it flowers and as you have but recently obtained this cultivar, your
(possible) flowering this past season may not be its true period. I don't
know this particular cultivar but it sounds very much as though N.
sarniensis is not a major contributor to its ancestry. Most of the
sarniensis hybrids will flower in early autumn, leaf growth occurs till
spring. Keep them going for as long as possible - regular light watering
and feeding maintains the foliage into late spring. Mine are showing some
browning of the foliage but some of the sarniensis hybrids are still
showing strong green leaf and there is still some leaf growth occurring. It
is a difficult judgment to know when to stop watering and finally let the
sarniensis based hybrids die down. Too much water late in the season may
lead to the rotting of the roots. In the dormant period, give a light
sprinkle occasionally. The object is to maintain the root system of the
bulb - too dry and the roots shrivel and you are likely to lose the flower
buds within the bulb, if not for the following season then for the season
after that, too wet and the roots will rot. There does appear to be a very
definite two year sequence for the bud initiation, development and
flowering for many of these nerines. This may be a contributing factor to
the non-flowering immediately following re-potting.

Hybrids that are mainly N. bowdenii based will maintain their foliage for a
longer period. They will also start their foliage into growth later with
often a very definite space between their flowering and leafing, just as
bowdenii tends to do outside. Some of these hybrids derived largely from
bowdenii are almost evergreen and if they are kept inside and watered and
fed they will keep their leaves or possibly show a very short dormant
period. I don't know whether the dormant period is necessary for flowering
to occur regularly but I suspect not. I just haven't observed any clues to
answer this question. Some of the sarniensis/bowdenii hybrids show this
tendency to evergreen strongly, e.g. Oberon, Kingship and Goya. (The long
growth period that results often leads to rapid offset production and
growth. :-) Just the sort of bonus we desire.) The bolt upright form of Eos
at this time of season suggests this group. Mark Wilcox mentions his "N.
sarniensis 'Eos' " as surviving the Washington DC winter outside. This
hardiness doesn't fit with an essentially sarniensis hybrid to me.

Some nerine species are naturally evergreen or will be so given suitable
conditions. These particularly include N. undulata (syn. N. flexuosa) and
these evergreen species have been used in hybrid development. these are the
ones which stretch the flowering period into December e.g. Elspeth,
Glensavage Spider, Kymina, Pink Triumph, Baghdad, Gloaming, Lochaber. The
leaf width and length in this group of hybrids varies considerably,
indicative of the use of a range of the species. Elspeth is notably narrow
shorter leaves; she bulks up quickly and the bulbs reach flowering
(relatively small) size rapidly. A hybrid like Oberon is still now showing
very vigorously upright foliage. clearly still in active growth. The
dryness faced by species in the open ground may be overcome by the roots
going deep.

You need to treat these other two group separately from the mainly
sarniensis group and I take care to keep the sets of pots apart, though in
the same greenhouse. I have found it handy to use a differently coloured
label for these three groups and for the species.

There are two frustrations for me with nerines. Firstly many of the records
of hybridization have been lost or, more rarely, I don't know where to look
for them. Secondly, the regulations on sending bulbs between countries
limit my acquisitive tendency!

There were a number of comments on seed sowing for nerine and other
amaryllids. Nerine seedlings can be kept growing without a dormant period
for their frost two or three years. Keep moist and they don't die down. I
don't know if this applies to the other amaryllids with fleshy seeds, but
Doug's comment on Brunsvigia shows it applies to some at least. When sowing
seed of this group, I use Alberto's technique of 'half bury'. I often find
some assistance in helping the radicle into a slit in the compost is
useful.

Mary Sue dug out some of Sir Peter Smithers comments for us on the question
of feeding. I have used a balanced feed often with these plants and I don't
have problems with it. I do get rapid offset growth. but the feeding cannot
be the cause of the virus. It may make bulbs more prone to softer growth
and hence more susceptible to insect attack which carry the virus. Mealy
bug can be such a source but regular preventive spraying holds this fairly
easily. Certainly, nerine are not easily taken by mealybug - unlike clivia
for example - but I have found insects at the base of the old flower stems
when re-potting. It is common to cut off the old flower stem when it has
died down and leave it in the bulb. However this appears to keep a channel
open for mealybugs to get to the base of the bulb where they are well
protected from contact insecticides. I suspect this may be one reason for
the suggestion of immersing the whole pots in an insecticide such as
Malathion that I have come across. I have practiced pulling out the old
stem fully when it has completely died down. It comes out very easily (if
it doesn't, it's too soon to pull!) and the growth of the bulb closes the
gap where the stem came up.

"Nerines flower better if pot-bound" is a comment that comes up. I think
this is in part a reflection of the good drainage that results from all
those penetrating roots! Its not just a matter of being undisturbed though
this plays a major part.

Mary Sue also commented earlier on the richness of my mix. One of the
factors that I think particularly important is the presence of the trace
elements. Geologically, the SA soils are strong on iron and other mineral
content and the ability of the nerine roots to go deep would enable the
bulbs to tap the deep-lying sources for trace elements.

Regards to all
Hamish
Wettish Zone 9
Middle South UK