This section is from the book "A Dictionary Of Modern Gardening", by George William Johnson, David Landreth. Also available from Amazon: The Winter Harvest Handbook: Year Round Vegetable Production Using Deep Organic Techniques and Unheated Greenhouses.
Allium fistulosum. This is a perennial, never forming any bulb, but is sown annually, to be drawn young for salads, etc. On account of its strong taste, it is greatly inferior to the common onion for this purpose; but from its extreme hardness in withstanding the severest frost, it may be cultivated with advantage as a winter-standing crop for spring use.
Two varieties are in cultivation, the white and the red; the first of which is in general use.
As it may be sown at all times with the onion, and is similarly cultivated, except that it may be sown thicker, and only thinned as wanted, the direction given for that vegetable will suffice. The blade usually dies away completely in winter, but fresh ones are thrown out again in February or March.
To obtain seed some of the roots must be planted out in March, six or eight inches asunder. The first autumn they will produce but little seed; in the second and third, however, it will be produced abundantly- If care is taken to part and transplant the roots every two or three years, they may be multiplied, and will remain productive for many years, and afford much better seed than that from one-year-old roots.
There is pood reason for concluding that by a confusion of names, arising from similarity of appearance, this vegetable is the true scallion, whilst the hollow leek of Wales is the true Welsh onion; for the description of scallion, as given by Miller, accords exactly with that of the Welsh onion. At present all onions that have refused to bulb, and formed lengthened necks and strong blades in spring and summer, are called scallions.
 
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