32 MASS. EXPERIMENT STATION BULLETIN 382 



a solution of 1 ounce in 8 gallons water rooted 86 percent in 30 days, 

 which was much better than the rooting of untreated cuttings or of those 

 treated with some ordinary root-inducing substances (75). 



Pyracantha, firethorn. Cuttings are taken in summer (67) or fall (124). 

 Untreated cuttings of P. coccinea taken here in early August rooted 100 per- 

 in sand-peat and in sand. October (98, 125) and November (83) cuttings 

 have also rooted well. Rooting is better if thorns are removed (42) and if 

 the basal cut is at a node (14). Indolebutyric acid hastened rooting (125), 

 but indoleacetic acid (50 mg./l., 24 hr.) was more effective (83) and also 

 improved rooting of cuttings of P. atlantioides (72). September cuttings of 

 P. crenulata rooted, in 35 days, 6 percent without treatment, 75 to 100 percent 

 after treatment with indoleacetic acid (25 mg./l., 20 hr.), a treatment which 

 was of more benefit to cuttings of P. coccinea made of tips of shoots rather 

 than their basal parts (68). December cuttings of P. coccinea rooted 82 per- 

 cent without treatment, 100 percent with Hormodin No. 1 (102), 



Pyrus, pear. Hardwood cuttings of most varieties of common pear are not 

 easily rooted, but some can be propagated by treated softwood cuttings. 

 Untreated cuttings did not root but those treated with naphthaleneacetic 

 acid (40 mg./l., 12 hr.) rooted 100 percent if made of growing shoots in 

 spring, 75 percent if taken in early summer when growth had recently 

 ceased (82). There was also good rooting of cuttings taken in spring 

 or early summer and treated with indolebutyric acid (20 to 40 mg./l., 24 

 hr.) (81); and 2 mg./gm. talc improved the rooting of early June cut- 

 tings of sand pear (49). Cuttings of Hood, an oriental pear, rooted 100 

 percent in sand-peat in three weeks after treatment for 24 hours with 

 Hormodin A (40 B T I units), not at all without treatment (117). 



Quercus, oak. Cuttings from other than very young trees are not likely to 

 root much without treatment. Untreated July cuttings of English oak 

 did not root, but there was 56 percent rooting of cuttings from trees 6 to 

 8 years old which had been treated with indoleacetic acid (50 mg./l., 

 18 hr.), 34 percent rooting of cuttings from a tree 20 years old similarly 

 treated with 200 mg./l. (65). Cuttings of red oak from mature trees 

 failed to root, but there was 82 percent rooting of February cuttings made 

 from the basal parts (wood more than one year old) of 4-year-old trees 

 which had been treated with indoleacetic acid (400 mg./l., 24 hr.), 22 

 percent rooting of untreated cuttings (109). 



Rhododendron. As may be seen by reference to the table, early summer 

 cuttings of some species root well without treatment. That is true also 

 of cuttings of R. japonicum, R. racemosum (88), R. laetevirens (90), R. lap- 

 ponicum (105), R. yunnanense, and R. indicum (106). Cuttings of most 

 azaleas (9), R. maximum (5), and the common evergreen hybrids have been 

 more difficult to root although cuttings of some, e. g., the varieties Boule 

 de Neige, catawhiense album, and purpurcum clegans, rooted well without 

 treatment iy"^)- 



Cuttings of many species root better or more rapidly after treatment 

 with indolebutyric acid, some effective concentrations of which are listed 

 in the table. For broad-leaved evergreen species and hybrids, a relatively 

 high concentration of indolebutyric acid (40 to 80 mg./l., 24 hr., or 12 

 mg./gm. talc (61) or 10 to 20 mg./cc. by the concentrated solution-dip 

 method (49) ) is usually needed. Cuttings of the hybrid album grandiHorum 

 taken here in late August rooted 62 percent in 5 months without treat- 

 ment, 92 percent in 3 months after treatment with 50 mg./l., 20 hr. 



