Narcissus and Daffodil

Production of Narcissus bulbs 99
of Narcissus tazetta ‘Ziva’ to freezing stress. Acclimatisation of bulbs by hardening at
2 °C was unsuccessful, but a single soil drench with paclobutrazol or uniconazole
produced daughter bulbs that were not injured by freezing at –2 °C for 12 hours.
Transport
For shipping bulbs, well-ventilated refrigerated containers (reefers) should be
used, preventing losses due to ‘heating in transit’ observed in earlier years. On
receipt, bulbs should be stored in well-ventilated, ethylene-free stores at 13–17 °C
(De Hertogh, 1989). De Hertogh et al. (1978) investigated hypobaric storage as an
aid to shipping. Bulbs were stored for 2 weeks at 76 mm Hg and 17 °C prior to
cooling: low pressure storage retarded bud growth, but eventual flowering was not
affected, compared with control bulbs stored under ambient conditions.
SPECIALIST TYPES OF NARCISSUS BULB PRODUCTION
As well as the ‘standard’ narcissus and daffodil cultivars, other types of narcissus
may be required, needing different growing techniques. These include Tazetta
narcissus, dwarf and small-bulbed cultivars and Narcissus species. Integrated crop
management and organic systems of growing are also considered.
Production of Tazetta Narcissus
Tazetta narcissus require a frost-free climate for natural-season growing. The
main producing country for Tazetta bulbs is Israel (Yahel and Sandler, 1986; van
der Weijden, 1988). Here, bulbs are planted in October, lifted in June and stored
at ambient temperatures (25–30 °C), which retard the bulbs naturally until temperatures
fall low enough to allow growth. Floral initiation takes place after lifting,
in July/August, and anthesis occurs before winter if other conditions are favourable.
The bulbs can be retarded by storage at 30 °C, producing late flowers in April or
May (Yahel and Sandler, 1986). In northern Europe, a suitable climate exists in
the Isles of Scilly, where the Tazetta cultivar ‘Grand Soleil d’Or’ (‘Sols’) is an
important crop, although bulb production here is secondary to the production of
the early, fragrant flowers (Veldt, 1988; Schaap, 1989). Cultural methods are
usually adapted from standard practices for the region (ADAS, 1970), but are
largely influenced by the local requirement to extend the flower cropping season
and to maximize flower, rather than bulb, yields. These procedures include leaving
crops down for several years (Tompsett, 1980b), early lifting and heat treatment
(Rees and Goodway, 1970), burning-over using a tractor-mounted propane
burner, and covering the crop with polythene film (Tompsett, 1980b, 1985).
Similar responses have been reported for other Tazetta cultivars, including
‘Paperwhites’ (Imanishi, 1983; Tompsett, 1985). Although bulb production from
Israeli bulbs in the Isles of Scilly is satisfactory in the first year, growth in the
second year is poor, because higher temperatures are needed (Vreeburg and
Korsuize, 1989). In unsuitable climates, or to enhance growth, Tazetta narcissus
can be grown under protection (Kim and Lee, 1982). As well as being unusual in
not having a cold requirement, narcissus of the Tazetta group characteristically