Central Plain States and Upper Mississippi Valley

Ruth and Emmet Layton, who have practiced landscape architecture successfully in the St. Louis area for years, write of the conditions they encounter as follows: "In general our greatest difficulties arise from heavy clay soil combined with cold and frequently open winters, with little snow cover. Our hot summers also pose a problem, and the combination of all these things limits our evergreen population severely. All highly acid soil plants are avoided, with the exception of kal mia, rhododendron and azaleas, which thrive in shade or semishade, provided there is plenty of peatmoss mixed with the clay at planting time to lighten its texture; with annual applications of aluminum sulphate for feeding and acidifica tion; plus, most important of all, a deep and permanent cow manure mulch, which, if maintained from two to three inches in depth will not grow weeds.

"Certain pests and diseases limit our use of other material. Red spider, for instance, is a serious handicap to the culture of junipers, philadelphus, and horsechestnut in particular, the latter two being completely defoliated in a hot, dry mid summer. Scale is also a ruinous pest to cotoneasters, certain euonymus, and cydonia (chaenomeles), while lilac mildew is thoroughly disfiguring to all syringa and to certain privets should we have a particularly humid season, which we com monly do.

"Certain cherished perennials, regarded as major standbys elsewhere, are quite chancy with us, due to extreme summer temperatures for the most part, plus our stiff clay soil. Del phinium, campanulas, and lupines, in particular, will simply cook if we get a bad summer, and are best raised from new seedlings every second year to replace those that fail to sur vive.

"On the other hand, the clay is extremely well suited to all members of the rose family from flowering crabs, apples in variety, to roses of all but the tender varieties. It is necessary to treat the floriferous types with a bimonthly spray or dust containing fermate, to destroy blackspot and mildew, plus all other assorted rose ailments-but we do not enjoy the rose beetle and are relatively free from the Japanese beetle as well.

"Iris does magnificently here. Peonies do well most years, but it is best to omit late-flowering varieties which might be blasted by high temperatures in mid-May. Dictamnus, like peonies, will grow well if it is once established, and the soil texture well-lightened beforehand."

LIST OF PLANTS FOR CENTRAL PLAIN STATES CONIFEROUS EVERGREENS