One of the most desirable of the trailing Evening Primroses is the one called the Genothera missouriensis or macrocarpa, which has the advantage of being cushion like.
Pretty either by day or in the evening, although it opens better at night than through the day. It is best known by the names given above, but some of the American botanists are inclined to remove it from the Cenotheras, and to call it by the weird name of Megapterium missouriensis, one not likely to gain favor here. It is a wonderful trailing plant, with stems occasionally only 6 inches long, but generally their about a foot in length.
It has thick narrow leaves and good flowers, which vary in some plants from 3 inches to 6 inches in width. These are of a clear yellow, and when a good plant is seen trailing over rock work, they look bright, particularly in the evening. Like others of its class, this Evening Primrose doesn’t like a cold and wet soil, and in such it is not generally long lived. In light soils in the south it will live longer than in the north, but it is advisable to raise a few seedlings occasionally to replace any plants which may be lost. I have generally found it a good idea to sow these seeds under glass, pricking out the resulting seedlings into boxes when large enough to handle, and finally planting them out where they’re to bloom. If sown in March under glass, the seedlings should be fit to plant out by June. This flower naturally grows in a dry soil in its native locations like Missouri and Nebraska and all the way down in Texas.