1. Effect of K level on frost hardiness of stems of Forsythia × intermedia Zab. “Lynwood”;Beattie;J. Am. Soc. Hortic. Sci.,1973
2. Nutrient-element composition of leaves from selected species of woody ornamental plants;Davidson,1960
3. A method for determining hardiness in plants;Dexter;Science,1930
4. Plant nutrition and woody ornamental growth and quality;Dirr;HortScience,1975
5. Geographic variation in Eastern Redbud;Donselman,1976