Rembrandt Yellow trumpet 
Carlton Incomparabilis 
Helios Incomparabilis 
Early Perfection Poetaz 
La Fiancee Poetaz 
Hints for forcing bulbous Irises 
The best Iris, generally used for forcing, are Dutch Irises, including 
filifolia and tingitana hybrids. 
These Irises are supplied in different sizes. The largest size are the 
most suitable for forcing, especially for early forcing. 
1. What to do upon arrival of the bulbs? 
Unpack the Irises immediately upon arrival and, if you cannot plant 
those you need for early forcing at once spread them out on the 
trays. Put the trays in a dry, well ventilated place. 
Irises wanted for late forcing, don’t have to be planted immediately 
upon arrival, but can be planted later in the season, even as late as 
the 15th of December. These bulbs should be stored in trays in a fairly 
warm and dry place. 
2. The planting. 
The vest soil for Irises is a well-drained sandy loam and it should 
be fresh and real moist soil. 
New pots or pans should never be used, unless they are thoroughly 
soaked in a water tank for, if possible, four weeks to avoid burning 
of the roots. It is obvious that all receptables used, must have proper 
drainholes. Flats and boxes should be at least 6 in. deep. 
Irises are often planted directly in the greenhouse benches (after 
other crops are finished). If this is done, these houses should be kept 
at a temperature of about £0 °F. to start with. 
After the bulbs are planted, they should be well watered. 
Irises in flats should be planted at least 2 in. apart; this counts es- 
pecially for Wedgewood, other varieties can be planted slightly closer. 
3. What to do with Irises after planting? 
If your Irises are not planted in the full ground benches, it is best 
to place the boxes and pots in a cool greenhouse, where these Irises 
are to be forced (temperature about 50 °F.) 
Once you have placed your pots or flats, it is necessary to leave 
them in the same spot. Never remove your pots or flats to another 
place, as the roots generally grow into the soil of the bench. This way 
you ll prevent serious disturbance of the roots, which is believed to be the 
main cause of blindness. 
If you are forcing Wedgewood only, yau can raise the temperature 
after the middle of December up to about 60 °F (Other Irises will not 
stand such a high temperature at such an early date). They like plenty 
of water and, if possible, this water should have greenhouse temperature. 
Best results are generally obtained if your Irises get plenty of light. 
There should be, throughout the period of forcing, sufficient ventilation 
of the greenhouse. When the buds are showing, water very sparingly. 
If you cannot place your Irises directly on the place where they are 
to be forced, it is also possible to store them in a bulbcellar or a root- 
house. It is advisable to move them into a cool greenhouse as soon 
as you have space available. 
lf you have no other choice, they also can be buried outside but it 
is necessary to move them into a cool greenhouse not later than No- 
vember. This is especially so for Wedgewood. The reason for this is 
to avoid disturbance of the roots. 
When digging in your bulbs outside, follow same rules as mentioned 
for other bulbs. 
4. Varieties suitable tor forcing. 
Dutch Iris ,,.Wedgewood” (which is also suitable for precooling) is 
recommended for earliest forcing, to be followed by: 
Golden Emperor White Excelsior 
Golden Harvest White Superior 
H. C. van Vliet Yellow Queen 
Imperator 
5. Culture of Irises in glasshouses without heating. 
(in districts only where the climate is suitable!) 
Bulbous Irises form splended material for growing in glasshouses in 
the open ground without heating. 
Plant rightaway on receipt of the bulbs, rather well spaced with 
regard to foliage formation. Varieties with much and broad foliage 2 
inches apart (from heart to heart), Narrow leaved varieties may be 
planted a little closer. 
The soil should be well prepared and nutritious (not used for Irises 
before). 
Crocus 
Crocus offer a welcome material for pots, especially for retail florists. 
Do not bring Crocus into the greenhouse until the sprouts are about 
1!/, in. and grow them cool. They do not stand heat. 
Yellow Crocus are not recommended for this purpose. 
Muscari 
Muscari armeniacum can easily be forced and with their bright blue 
flowers, which keep well, they are ideal for corsagework. Also recom- 
mendable for pots and small pans. 
They can be precooled succesfully. 
