Nerine matters

Hamish Sloan hamish.sloan@virgin.net
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


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