240 STATE HORTICULTURAL SOCIETY. 



§ 2. Cultivation of the Native Plums. 



1. Impotent varieties. Planting. — It is not strange that difficulties 

 should beset the cultivation of fruits which are yet scarcely rescued from 

 a wild state. The chief difficulty in the growing of the native plums is 

 the fact that some varieties do not fertilize themselves. This peculiarity 

 appears to be due not to any imperfection in the flowers but to the com- 

 pai'ative impotency of pollen upon flowers of the same variety. Imperfect 

 flowers are occasionally observed, but they are apparently peculiarities of 

 individual trees or particular seasons. Thus in our Newmans this year 

 only about every twelfth flower has a perfect pistil. I have observed a 

 similar defect in wild plums. I know a wild tree of Primus Americana 

 which bears flowers without pislils. The impotency of pollen appears to 

 be characteristic of certain varieties, as, for example, Wild Goose, Miner, 

 Wazata, Minnetonka, Itaska. Other varieties of the same species are fer- 

 tile with themselves, as Moreman, Newman, Wayland, Golden Beauty, 

 Marianna, Deep Creek, Purple Yosemite. In order to insure fertilization, 

 mixed planting is practiced when the impotent varieties are grown; and it 

 is an important study to determine what varieties are the best poUinizers 

 for a given kind. Evidently, the two varieties in any case must bloom at 

 the same time and the poUinizer must produce an abundance of pollen. 

 Thus the Newman is a good pollinizer for the Wild Goose, but it blooms 

 too early for the Americana varieties. In some of the western states, 

 Forest Garden is considered to be a good pollinizer for Miner. It is a 

 common opinion among plum-growers that the common or Domestica 

 plums, the peach, and even the cherries will fertilize the Wild Goose. 

 There is certainly much general evidence in support of this opinion, but it 

 remains to be proved. A case within my own experience lends color to 

 this opinion. A half dozen large trees of Wild Goose were barren until 

 trees of plums and cherries about them bloomed profusely, when the Wild 

 Goose bore a heavy crop. 



There is much difference of opinion concerning the methods of planting 

 in order to secure fertilization. Many growers advise planting in thick 

 hedge-like rows, the trees standing not more than four or eight feet apart 

 in the row, every fourth or fifth tree, or every alternate row, being a self- 

 fertile and very polliniferous variety. Others practice setting the trees 

 from nine to twelve feet apart each way, with the impotent varieties in 

 alternate rows. In this way, for example, Forest Garden is made to 

 fertilize both Miner and Wild Goose. This treatment is commonly known 

 as "close planting," and it has many able advocates. It is said, also, that 

 this close planting shades the ground so completely as to make it too cool 

 for the rapid development of the curculio. Such plantings, unless the trees 

 are heroically trimmed, soon result in an unmanagable tangle. I have seen 

 a Wild Goose tree 86 feet across and still growing and bearing, and Miner, 

 Leptune, and Langedcn scarcely less. Mr. Kerr, who is a very successful 

 grower, sets his trees from twenty to thirty feet apart, and others have 

 good success with equally thin planting. It is probable that different 

 varieties or combinations demand different treatment in this respect; but 

 it is plain that while the majority of native plums appear to be self -fertile, 

 some of the most important varieties are impotent. 



2. Propagation. — Another important difficulty is that relating to the 

 selection of stocks. The native species work well upon each other, but 

 the permanency and strength of the different unions are still moot points. 



