Delphiniums in Bloom
By L. H. Leonian
Sometime in June, Delphiniums begin to bloom in most parts of our country. This is an important period in the life of the plant. Where nights are cool and the atmosphere humid, the mildew will be at its worst. Dusting with sulfur or spraying with Bordeaux will control mildew. Although less harmful to plants, sulfur is also less effective against many fungous diseases than Bordeaux, the universal fungicide which, unfortunately, tends to burn the foliage under certain environmental conditions.
Mite also will make its presence more noticeable just before or during the blooming period. Spraying with rotenone should be kept up. If the month happens to be dry, artificial watering will give longer flowering spikes.
For better cut flowers. Those who grow Delphinium for cut flowers will get more satisfactory results by removing the buds of the main spike as soon as possible. This stimulates side shoots which will form in greater numbers and attain unusual lengths. Laterals fit much better into flower arrangements than very large, formal spikes.
Many persons save their own seeds. In Nature, cross pollination of Delphinium is much less frequent than is commonly believed; selfing is the usual rule. When hybrid plants like Delphinium are selfed, the seeds thus formed will carry the less desirable characters of their ancestors. This is why seeds from very fine parents usually give rise to poor or mediocre progenies.
How to cross Delphiniums. The experimental minded gardener should try his hand at crossing his Delphiniums and thus produce seeds far superior to selfed sorts. The process is very simple and anyone can cross Delphinium. As soon as the flowers open, grab the anthers between the index finger and thumb and pinch them all off with one motion. The petals or the "eye" may be included in this pinching operation in order to clear away the central portion of the flower. Within two to four days, depending upon weather, the female reproductive organs will push up three or more filaments the tips of which constitute the pollen receiving apparatus. This is the time to apply pollen.
One should select the pollen-furnishing flower early in the morning and examine the anther for mature pollen. It will be seen that some anthers have already shed their pollen which appears as a grayish, sticky mass of powder. Fold back the sepals of the flower in order to expose the matured anthers, and gently touch the pollen mass to the tip of the filaments of the emasculated flowers. That is all there is to it; the cross is made. As not all of the flowers on the spike open at the same time, it will be necessary to go over the spike every day and remove the anthers. In the meantime the spikes should be covered with cheesecloth bags to prevent any occasional pollination by bees.
If one needs but a limited supply of seeds, one need not pollinate more than a few of the lower flowers on the spike. In any case it is best to remove all side shoots in order to economize on the energy of the spike.