Rooting Ability Of Native Cottonwoods 

/ 

Depends On The Clone, Used 

Vegetative propagation of eastern cottonwood (POPU~US 

deltoides) from dormant cuttings has generally been considered rather easy. Yet test plantings of unrooted cuttings 

of this species on the Hopkins Memorial Experimental Forest 

at Williamstown, Mass., showed considerable variation in 

rooting ability of the clones used. 

In the spring of 1953, dormant unrooted cuttings of 

30 cottonwood clones were planted in a test plantation to 

compare their performance with that of 30 hybrid poplar 

clones. Cuttings for 15 of the cottomood clones were collected from young trees growing along the banks of the 

Hoosac River in Pownal, Vt. Cuttings representing 15 other 

cottonwood clones were supplied by the Maria Moores Cabot 

Foundation; these clones were originally from several widely 

scattered sources in the United States. The hybrid poplar 

clones were from the original hybrid poplar plantations in 

Maine. l 

All cuttings were taken from wood that had formed in 

1952. They were cut to a' uniform 12-inch length and were 

graded roughkg from a 3/16-inch to a 1/2-inch middle diameter. The hybrid stock, and presumably the Cabot stock, 

were taken from stool plantations that are cut back annually. 

The Pomal stock mas from trees that ranged in age from 3 to 

10 years. They had not been cut back. 

All cuttings wereplanted at 4 by 4-foot spacing on 

prepared ground. They were kept cultivated to contra1 weeds. 

Plantings were made on two sites and were replicated twice 

at each site. The arrangement of the clones in each replicate was random, 

1 Schreiner, Ernst J. Poplars can be bred to order. 

U. S. Dept. Agr. Yearbook 1949: 153-157. 1949. 
No , Percent Percent Percent 

P. deltoides from-- 

' !i 

Table la-- 

Pownal, Vermont 15 55 3 19 

Cabot Foundation 15 100 38 70 

Hybrid poplars 30 100 92 98 

C %, Species and source 

'~vera~e of four replicates. 

Approximately one month after planting, the plantations were examined for survival. The hybrid poplar clones 

rooted best (97.5 percent), then the Cabot stock (70.3 percent), and the Pownal stock (18.9 ~ercent) . 

The 15 Pownal clones showed the widest range in rooti 

Clones 

tested 

ing, from an average low of 3 percent for all four replications to an average high of 55 percent. The Cabot stock 

ranged from 38 percent to 100 percent. The 30 hybrid poplar 

clones showed the greatest uniformity in rooting: all replications averaged better than 92 percent. 

Cuttings rooted1 

The poor rooting and the variation in rooting ability 

of the Pownal clones may be due to some extent to the fact 

that the cuttings were taken from trees that had not been 

cut back as the source trees of the other clones had. Since 

this test, the P~wnal trees have been cut back and stool 

cuttings will be available for planting next spring. Then 

we can detedne if stool cuttings root more readily than 

stem cuttings, 

Maximum 

The uniform and high percentage of rooting of the hybrid poplar clones can be attributed to the careful selections made for rooting ability among the thousands of hybrid 

clones that were established in the original hybrid poplar 

plantations in Maine. 

--FRANK E. CUNNINGHAM 

Minimum I Average 

2 

Agriculture-Forest Service-Upper Darby