QBARS - v2n4 Fertilizing


George C. Grace, Secretary
American Rhododendron Society, Box 8828, Portland, Oregon

Dear Mr. Grace: in talking to a number of parties who have only a small number of rhododendrons I find there is a great deal of confusion as to fertilizing and watering the plants. One party who has about ten plants, some of which are good, newer varieties, used the following chemical formula last year:

1 lb. ammonium sulphate
3½ lbs. super phosphate
2 lbs. sulphate of potash
2 lbs. cotton seed meal
1 lb. aluminum sulphate

The new leaves soon turned brown on the ends and sides and dried up. The plants set only a few buds, some of which opened to good flowers this year, others into deformed flowers, and others dried up. One commercial grower told him that he had either used too much fertilizer or had given the plants too much water, and that rhododendrons do not need fertilizer. Another commercial grower told him that this trouble was caused by chemical fertilizer-that he should use weak liquid cow manure immediately after blooming to stimulate new growth, and that only if the plants seemed to need stimulating, to give them lots of water, but never use chemicals. Still another told him to use cow manure as a mulch in the fall when the rains start. Others recommended chemical fertilizers only. You can readily understand that this man is badly confused and somewhat discouraged, and there are others just like him, and complains that he cannot find any article on the use of fertilizers which a rank amateur can really understand. He probably used too much fertilizer and not enough water.

Having this in mind it has occurred to me that an article on fertilizers for rhododendrons and their use in a Society Bulletin would be very valuable and much appreciated by many members. This article should contain a formula for a chemical fertilizer and give specific directions for its use, that is when and how much per plant and not how much per 100 square feet should be used, as amateurs are inclined to use too much. Also when and how cow manure should be used. It might also contain some instructions on watering.

Yours truly,
Jas. M. McConahey