596 " IOWA DEPARTMENT OF AGRICULTURE 



location. In the northern part, however, there has been considerable 

 trouble from this cause. For this reason it is not advisable to plant 

 catalpas in extensive plantations in the extreme northern and especially 

 in the northwestern part of Iowa. 



North of the line drawn between Harrison and Monona counties, and 

 continued eastward across the state, catalpa plantations should be pro- 

 tected by a windbreak of hardier trees planted along the north and west 

 sides of the grove. Three or four rows of cottonwoods or willows afford 

 plenty of protection. 



FORM AND SIZE. 



When planted in groves the hardy catalpa reaches its best develop- 

 ment form in sixteen to twenty years. Trees in single rows require a 

 much longer time to reach their full development. Closely planted 

 catalpas develop a tall, slender trunk, with very few large branches. 

 The height of sixteen to twenty-year-old trees varies from 30 to 40 feet. 

 The diameter of 35-foot trees, measured one foot above the ground, is 

 about 7 or 8 inches. The trees hold their diameter well, and will usually 

 cut out three 6%-foot posts. As the catalpa continues to grow until late 

 in the fall, the top 6 inches or so does not mature and is frozen. The 

 next spring the growth starts from a bud below the injured portion, 

 causing a slight crook in the 'trunk. This makes the catalpa undesirable 

 for telegraph or telephone poles. Also, it is seldom that the trees reach 

 pole size without becoming affected by fungus. When used for posts, the 

 trees can be cut before they become affected with the fungus. The slight 

 crookedness does not detract seriously from the value of the posts. 



SELECTION OF SPECIES. 



The most common cause for failure with catalpas is a mistake in the 

 selection of the species to be grown. There are two native species of 

 catalpa in the United States, the hardy catalpa (Catalpa speciosa Warder) 

 and the common catalpa (Catalpa catalpa Karst). The common catalpa 

 is not hardy enough to be grown successfully in Iowa. Hardy catalpa 

 seeds are very wide, with a broad brush of hairs at each end and a fringe 

 of hairs along one side. Seeds of the common catalpa are much narrower, 

 with a narrow, pointed brush of hairs at each end. Hardy catalpa seed 

 pods are 7 to 20 inches long, with thick, strong walls. There are seldom 

 more than three in a cluster. Common catalpa seed pods are 6 to 18 

 inches long, with thin walls. From 5 to 15 pods gr.ow in a cluster. The 

 bark on old stems of hardy catalpa is deeply furrowed, but never peels 

 off in scales. That of common catalpa is thin and light, falling off in 

 light scales, but it is never deeply furrowed. The two species of catalpa 

 cross readily. Bees sometimes carry the pollen as much as two miles. 

 Thus it will be seen that great care is necessary in order to obtain pure 

 seed of the proper species. 



The seed pods ripen in October. They may be gathered as soon as 

 ripe or allowed to hang on the trees until January or February. When 

 gathered they should be sacked and stored in a dry room. Within a 

 few weeks the pods will split open upon the slightest disturbance and 



