o 



26 



Garden and Forest. 



[September 5, 



interior portions of this continent, they largely increase 

 its value. As long as Congress permits the devastation 

 of our western mountain-forests to go on unchecked 

 and unpunished, efforts to secure a comprehensive and 

 permanent system of irrigation for the western States and 

 Territories can never succeed. Reservoirs are valuable 

 adjuncts to the forest in maintaining a water supply for 

 large irrigating enterprises ; but unless the forests are 

 preserved, as an initial step, permanent and valuable 

 results cannot be hoped for. 



A recent issue of the Revue Horticole calls attention to 

 the great value of the little known Iris pahularia, the 

 Krisiiam of Cashmere, as a forage plant. This plant, it 

 appears, will flourish in the driest and most arid soil, and 

 once established it cannot be exterminated. The leaves, 

 which attain a height of twelve to sixteen inches, are 

 eaten by cattle either green or dried, the same plant 

 producing two or three crops of leaves in a season. It 

 is recommended that the seeds should be shown in beds, 

 and then that the young plants should be set very early 

 the following spring where they are to remain. They 

 should be planted in rows ten inches each way if 

 the soil is very poor, and fifteen to twenty inches apart 

 in richer soil. A thorough watering will aid the plants to 

 make a good start, should it be dry when they are set. It 

 is doubtful if Iris pahularia will prove hardy in the Northern 

 States, but it should certainly be tested in California, and 

 ,in our dry south-western region, where, as well as in 

 Florida, it may be destined to play an important part in 

 the rural economy of all that part of the country. Seed 

 can be obtained from the Messrs. Vilmorin, of Paris. 



The Treatment of Slopes and Banks. - 



IT is a common mistake, where a road or a flat surface 

 of turf is to be formed at a different elevation from 

 that of the adjoining ground, to gi\'e the bordering banks 

 too nearly the form of inclined planes, and to make them 

 too steep, as at a 3 c in the diagram. Such slopes at the 

 outset, while all about them is raw, are comparatively 

 neat, and they can be formed cheaply by unskilled la- 

 borers, with little guidance or thought on the part of those 

 in direction. They are objectional)le, first, because it is 

 difficult and costly to keep them in good order. On such 

 steep slopes, the drainage is either too quick, in which case 

 the grass upon them suffers from drought, or, on the other 

 hand, subsoil water finds an outlet through the bank, mak- 

 ing its surface soft and easily washed. Such a bank, there- 

 fore, needs to be protected by the best possible turf. But if 

 the slope is in " kept " ground, it is difficult to form or main- 

 tain good turf upon it. Neither scythes, lawn-mowers nor 

 rollers can be used to ad\-antage, nor are manures apt to be 

 evenly distributed upon it. Consequently, the turf soon 

 falls into bad condition. If the ground is pastured, as is 

 often desirable in case of a park-like treatment, cattle go- 

 ing up or down the slope poach and gouge it. In either 

 case the grass soon grows in tufts, and the character of a 

 continuous web of turf is lost. Storms wash out the soil 

 between the tufts, and then freezing and thawing and 

 further washings soon bring the whole surface to a sorry 

 condition. 



By lessening the inclination of the surface, difficulties 

 of the class thus explained may be overcome. But there 

 will remain, however, another and a more important ob- 

 jection to banks in the form of regularly inclined planes 

 in most situations. They are stiff, formal and plainly ar- 

 tificial. Recognizing that they are so, it seems to be often 

 supposed that the only revision of them necessary to a 

 satisfactory result will be secured if a surface can be 

 formed of a single, uniform, convex curved cross-section 

 — like the front part of an upholstered, spring-seated sofa 

 — made to meet the road or grass-plot at an abrupt angle, 

 as one would trim down the edges of a pie before bakmg. 

 (Shown by the line (/e in the diagram.) Such a slope is 



really not less formal than an inclined plane. To make 

 it less so, the top of the slope may be thrown back from 

 its base further at some points than at others. But it will 

 yet have a very unnatural aspect. 



The reason of this is less difficult to understand than 

 might be supposed, judging from the frequency with 

 ■which such banks are seen in very costly works of land- 

 scape gardening, so-called. 



A continuous body of good turf implies a continuous 

 body of deep, friable soil. If the effect of a single rain- 

 storm upon a body of such soil thrown up in a pile of con- 

 vex section is carefully observed, it will be seen that a 

 portion of the soil is washed out upon the adjoining level 

 surface, obliterating the angle where the original slope 

 met it, and making the lower part of the slope concave. 

 (Shown by the lines ijk in the diagram.) The longer the 

 bank of soil remains bare and subject to the wash of rain, 

 the more it will spread at the bottom, and the less will 

 remain of the original convex section. 



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Fig. 51. — Good and Bad Slopes. 



Further than this : as a natural bank of loam rarely oc- 

 curs that is of uniform consistency throughout, the action 

 of the weather upon it will seldom produce a curved slope 

 of the same cross-section at all points,, and its outlines 

 will, consequently, become \'aried and informal. 



The lesson to be learned from observation of Nature in 

 this matter is that it is a safe general rule, in making a 

 sloping bank, to give it an "ogee" cross-section. (An 

 "ogee'' is an architectural term, meaning a moulding the 

 upper part of which curves outward and the lower inward, 

 or, more broadl)% any rcA'ersed cur\'e, such as "Hogarth's 

 line of beauty," used in school copy-books for the stems of 

 many of the capital letters. It may be illustrated, in a prac- 

 tical wa)'', by grasping a thin elastic rod with one hand at 

 each end, and then bending one up and the other down.) 

 The line f gh is a regular ogee curve, the concave portion 

 f g being equal in length and shape to the con\'ex portion 

 g h. As a rule, the proportions of the curve should be 

 varied from time to time, so as to produce an undulating 

 surface — graceful, if grace is a quality to be desired in the 

 locality, but in all cases informal and natural. A slope 

 may have at one place a cross section like / m n in the 

 diagram, in which the concave part of the slope / in is 

 shorter than the convex part 111 n, while a short distance 

 away the slope may resemble the line p q, in which the 

 relative importance of the concave and convex parts is 

 reversed. 



The diagram illustrates another principle in regard to 

 slopes. If abroad, grassy surface had to terminate at a steep 

 slope, falling to a road or fence, it would, presumabl}^, be 

 best to connect the broad surface with the steep one b)' 

 means of a long convex curve, as at m n, completing the 

 desired ogee slope by a short convex curve, as at I ni. On 

 the contrarjr, if the broad, grassy surface had to terminate 

 at a steep slope rising to a fence, terrace, shrub border, or 

 other marked boundary, the concave curve ought to pre- 

 dominate, as in the line o p q. In other words, the slope, 



