WILL YOUR TULIPS COME BLIND? 



A. B. STOUT 



Director of the New York Botanical Garden Laboratories 



Failure to Flower One Year May Be Overcome the Next — Summer 

 Growth a Critical Stage for Flower Foundation in the Bulb — Benefit of Early Summer Planting 



[OT infrequently Tulips "come blind" or fail to flower, 

 and when the number of such plants in a display plant- 

 ing is large, the color effect that was foreseen last fall 

 is greatly impaired, to the disappointment of the grower, 

 who perhaps indulges in some hard reflections on the bulbs and 

 their source. 



A blind Tulip, of the type very commonly seen, is one that 

 does not bloom, but whose bulb is of such size that a flower was 

 to be expected from it. It produces one or more green foliage 

 leaves, but the upper part of the stem ends in a mere blackened 

 stub. The flower is completely blasted and dead, and the plant 

 has the appearance shown in the accompanying illus- 

 tration. Such a blind plant is quite different from 

 a purely vegetative plant grown from bulbs of small 

 size and having only a green vegetative leaf directly 

 from a bulb scale. Such small-sized bulbs are not 

 sold by the bulb producers, but are grown for one or 

 more years in a vegetative condition until they 

 become of the size for blooming and producing large 

 flowers, and of course occur in the garden when the 

 flowering bulb "multiplies" into a number of younger 

 ones. 



The excessive blindness that occurred among large 

 display plantings of certain Tulips at the New York 

 Botanical Garden a few years ago gave opportunity 

 for a study of the conditions involved which led to 

 some definite conclusions as to the cause of blindness 

 and how it may, in some degree, be avoided. 



The possibility of fungous infection as a cause of 

 blindness has been carefully considered. A parasitic 

 fungus (Botytris parasitica) causes death and decay 

 of bulbs, stems, and leaves and is sometimes very 

 troublesome to Tulip growers, especially in Europe. 



little as one gram. All were sound and solid. They were 

 weighed, numbered, stored in a cool, dark basement during 

 summer, and properly planted out-of-doors in the autumn. 

 With very few exceptions, the first bulb and often also the second 

 in size obtained from these blind parents produced fine, vigorous 

 plants with excellent flowers. The plants ceased to be blind, 

 made robust growth, and showed no sign of being "run down" 

 and worthless. Such results show that, if properly handled, 

 blind plants of Tulips may bloom splendidly in a following 

 season. 



In these tests, bulbs of a surprisingly small size produced 



BULBS OUT OF SOIL AND STORAGE 



Bulb of La Reine (left) from soil in autumn; bulb of La Reine (centre) from 



storage at time of planting; a Darwin bulb (right) from soil on same date as La 



Reine and showing the later development of flower stalk in that group 



It is, however, evident that this fungus, although sometimes 

 present on blind plants, is not the cause of the blindness usually 

 seen in Tulips. 



Growers of Tulips sometimes believe that blindness is due to 

 a "weakened" or "run down" condition of bulbs. In order to 

 obtain evidence on this point, bulbs of blind plants of such 

 varieties as Rose Grisdelin, Cottage Maid, Chrysolora, and 

 Crimson King were dug at the end of their growing season. 

 The new daughter bulbs had formed as lateral buds to the 

 mother bulb (which had, of course, died after blooming) and 

 were of various sizes, the largest or first bulb of a set weighed 

 from ii to 40 grams while the smallest sometimes weighed as 



HOW "BLINDNESS" WORKS 



Above at left are two fine flowering plants from sister bulbs of a "blind" mother 



bulb of the previous year. Blind plants do not remain blind year after year but 



with proper handling come into bloom again. At right are two "blind" specimens 



showing completely blasted flower stalks 



flowers. In some cases an entire set of as many as six sister 

 bulbs bloomed, the smallest of which weighed only 2| grains 

 (which is less than 1-10 of an ounce) and was scarcely larger 

 than the end of one's little finger. Small bulbs lateral to a 

 large bulb and enclosed in its outer scales sometimes bloomed 

 as shown in accompanying photograph. When such small bulbs 

 form flowers instead of remaining vegetative for a year or two 

 and becoming larger, they are often unable to make new laterals 

 except of very small size, and often they make none at all. 

 The blooming of small bulbs is undoubtedly one of the condi- 

 tions that causes a planting of Tulips to "run out." 



IN THE further search for the conditions causing blindness, 

 special study was directed to the changes that occur in Tulip 

 bulbs during the summer. When a bulb is left in the earth 

 during the summer, roots are formed which make vigorous 

 growth and obviously take water into the bulb. Important 

 changes also take place within the bulb. If a large bulb be 

 taken from the ground late in summer or early in autumn and 

 cut open lengthwise the already formed flower is found. The 

 stem with its leaves and flower is all ready like a "Jack in the 

 Box" to push up through the earth. Summer is, hence, not a 



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