Producing Natural Effects in Conservatory Planting 



By W. W. Ohlweiler, Missouri 



The arrangement of the plants in large cunservato- 

 ries is influenced by a number of factors whose ulti- 

 mate influence, if we may judge from examples of large 

 conservatory plantings in this country, tends to bring 

 out the artificial character of the surroundings. To 

 these examples there are notable exceptions such as 

 the fern house at Garfield Park, Chicago, and parts of 

 a number of other conservatories throughout the coun- 

 try. In general we know that the dominance of the 

 greenhouse structure together with the ftirmality nl 

 "the walks, of the benches, and of other artificial fea- 

 tures, all tend to make the work of "'landscaping" a 

 greenhouse interior a rather ditfrcult proposition. Just 

 as the landscape designer is often called upon to plan 

 for the improvement of a poorly located building, so 

 the grower of greenhouse plants is often called upon to 

 do impossible things with impossible buildings. Of 

 course commercial ranges are exceptions as a rule : but 

 conservatories are, unfortunately, usually built first 

 and the planting arranged for afterward. The work on 

 greenhouse interiors is still more difficult because of 

 the nature of the plants tn l)e used. Palms and other 

 tropical plants are usually not available in the sizes 

 or in the quantities that outside plants are, and fur- 

 thermore their beauty only becomes apparent when 

 after decades of growth they begin to approach their 

 maturity. And then possibly their maturity is prevent- 

 ed because of the insufficient height of the house. The 

 greenhouse always places certain limitations on the 

 extent to which tropical specimens may be developed: 

 and for this reason the conservatory should be planted 

 primarily lor the few specimens which it is to contain 

 wdien th'ev have reached their maturity. Those who 

 are familiar with the large Phoenix at Washington 

 Park conservatories, or the large .\ttalya at Fairmount 

 Park, must have been impressed with the size to which 

 palms will grow under cnltivat-on and will take good 

 care that such palms as they are fortunate enough to 

 plant are fortunate enough t.. have room in which to 

 grow. There comes to my mind, as I write, a certain 

 small conservatory, perhaps thirty-five feet high, where 

 two Latanias are beginning to take the roof off. and 

 wdiere the owner is contemplating cutting them down 

 in the spring to save the houses! Less than a year 

 ago we were presented with a large Cocos Romanzof- 

 fiana and a large Arenga Saccharifera that were be- 

 coming too large for a forty-five foot house. The 

 former was growing in the n])en and has not apparently 

 recovered as yet ; the latter however was growing in a 

 tub and is now doing well. So before planting out our 

 conservatories it might be well to stop a moment and con- 

 sider a little of what the future may have in store for 

 the plants we use, so that when they reach their good 

 old age, and we too reach the years of plenty, we shall 

 not be forced to destroy them because we have not 

 been far sighted enough. So then let me repeat that 

 we must construct our conservatory for the plants 

 which it is to contain, or else we must use pretty good 

 judgment in our selection of the plants we put into it. 

 The' arrangement of the average conservatory is usual- 

 ly governed bv the amount of money at the disposal of 

 the^builder, and the design of the house, the arrange- 

 ment of the heating pipes, etc., are designed accordmg 

 to cost. False notions of economy of space, of heat 

 radiation, are responsible for many objectionable fea- 

 tures of modern conservatories. Certainly the arrange- 



ment of the walks, or the location of the heating sys- 

 tems, should not be such as to make for formality. 



The placing of the heating pipes in a conservatory 

 determines to a certain extent the location of the walks. 

 Usually the walks follow the outlines of the house with 

 the heating pipes at the outer edge of the walk or 

 directly under them. This means the location of the 

 plants in the central area. This system is usually ad- 

 \ised because the lowest part of the greenhouse is 

 usually at the sides and at the ends and by locating 

 walks at these points but very little headroom is lost 

 to the plants. Then again it is argued that walks in 

 the center of the house take up valuable planting room. 

 The correctness of this point of view is very much to 

 be doubted. \\^alks through the house certainly do not 

 prevent the development of plant roots under them, or 

 the develo])ment of foliage above them, and an over- 

 arched walk is one of the beauties of any greenhouse. 

 Radiation of heat directly from the pipes either uiuler 

 or at the sides of the boundary walks is neither com- 

 fortable for visitors or healthy for the plants. Another 

 objectionable feature of outside walks is the tendency 

 to mass the larger palms and tropical plants in the 

 center of the house where they are not easily seen. 

 certainh' nothing is more annoying to the plant lover 

 than to be forced to observe a good specimen at a dis- 

 tance when the walk might just as well have carried him 

 near it. 



In the new conservatories of the Missouri Botanical 

 Garden many of the objectionable features mentioned 

 above have been eliminated. This has been made pos- 

 sible largely because the particular type of construction 

 used gave a verv high arched roof which had the advan- 

 tage of permitting the planting of large specimens within 

 a very few feet of the outer edge of the conservatory. 

 Furthermore, tlie heating pipes were all located on the 

 boundarv wall and do not extend from the wall over 

 fifteen inches, and do not project above the foundation 

 sill, which is about three feet higher than the door sills 

 of the house. In order to prevent lateral radiation 

 directly from the pipes a concrete wall was built entirely 

 around the conservatory next to the pipes. This wall 

 extends from the floor level, which is that of the door 

 sills, to the height of the foundation sills, and is strong 

 enough ffour inches thick) to withstand the pressure of 

 the earth piled against it. The earth in the house was 

 graded from the floor level to the top of this protecting 

 wall in mo5t cases and gave a distinctly pleasing varia- 

 tion in the elevation of the surface and with the planting 

 helped to hide the side walls of the house from the in- 

 terior. Except at a very few points the heating pipes 

 cannot be seen, yet the\' are easily reached in case of 

 necessity. The walls are not reinforced. In a few 

 houses the grade of the surface is carried considerably 

 below that of the door sills but it is always carried up 

 to the top of the protecting wall near the heating pipes. 



The walks in all the houses with the exception of that 

 of the floral display house are four feet wide, and con- 

 nect one house witli the other by pleasing natural curves. 

 The walks are made of cinders about eight inches deep, 

 being finished at the surface with the same material 

 screened, and top dressed with yellow sand. The walks 

 are bordered with porous limestone and the soil at the 

 edges of the walk is always a little higher than the walk 

 itself. This walk, which now has been down a little over 



