This Subcordata plum is one of the standard food products of the aborigines in the region in which it grows, being eaten either raw or cooked; and it is sometimes dried in considerable quantities at the harvesting places and carried considerable distances to the Indian villages.[126] The trappers, the first men to enter the habitat of this plum, followed by the gold-seekers and ranchers, all knew and esteemed the fruit. The early settlers regarded it as the most useful of all the wild fruits of the Coast and attempts were made at an early date to domesticate it. Of these Wickson says:[127]
“In 1856 there was, on the Middle Yuba River, not far from Forest City, in Sierra County, a wayside establishment known as ‘Plum Valley Ranch,’ so-called from the great quantity of wild plums growing on and about the place. The plum by cultivation gave a more vigorous growth and larger fruit. Transplanted from the mountains into the valley they are found to ripen earlier. Transplanted from the mountains to a farm near the coast, in Del Norte County, they did not thrive. One variety, moved from the hills near Petaluma in 1858, was grown as an orchard tree for fifteen years, and improved both in growth and quality of fruit by cultivation.... Recently excellent results have been reported from the domestication of the native plum in Nevada County, and fruit shown at the State Fair of 1888 gave assurance that by cultivation and by selecting seedlings valuable varieties can be obtained. It is stated that in Sierra County the wild plum is the only plum which finds a market at good prices, and that cultivated gages, blue and egg plums scarcely pay for gathering. The wild plum makes delicious preserves.”
In its typical form Prunus subcordata is a shrub and is often only a low bush but under the most favorable conditions it attains the dimension and shape of a small tree. In its roundish, roughish leaves it so closely resembles the Old World types of plums that it becomes the nearest approach to them to be found among our American species. But in the globular, red or purple subacid fruit it betrays its affinity to the American plums, as it does also in the flat, sometimes turgid, smooth stone to which the flesh tenaciously clings. The flowers are white, fading to rose and borne abundantly, making the plant an attractive ornamental in blooming time as it is also in the autumn when the foliage turns to brilliant red, scarlet or crimson with touches of yellow. The fruit is sometimes so poor in quality as to be inedible but on the other hand is sometimes quite equal to some of the cultivated plums, especially in its botanical variety, Kelloggii.
That the fruit is capable of improvement by the selection of seedling varieties and useful in hybridizing with other species can hardly be doubted. Luther Burbank, under date of December 6, 1909, writes in this regard as follows:
“The Prunus subcordata, as it grows wild, bears very heavily even on bushes two and three feet in height, bending the bushes flat on the ground when the fruit is ripe. This is a very beautiful sight. The wild ones, although almost invariably bright red and spherical, are sometimes, though rarely found, yellow. When the seed of the yellow fruit is planted a certain portion of red ones are produced, but all, practically, of the same size and quality as the original. The trees of Subcordata in the wild state are greatly variable in growth, generally much more so than in the fruit. The fruit, however, varies much in quality, but it is promiscuously gathered by those living in the vicinity of the plum grounds and considered most excellent for cooking. I commenced working on this species about twenty-two years ago and have not carried it on as extensively as with the Maritima, as I found it subject to plum-pockets, but by very careful selection I have produced most magnificent plums, oval in form or round, sweet as honey or sweet as the French Prune, greatly enlarged in size, tree improved in growth and enormously productive, the different varieties ripening through a long season. Most of these are light and dark red. Some of them, when cooked, are far superior to cranberries, having the exact delicious flavor so much liked in this fruit, and the same color.
“From the crosses of Subcordata with the Americana, Nigra, Triflora and other species, some of the most beautiful and highest flavored fruits which I have ever seen have been produced. These vary in color from almost pure white to light yellow, transparent flesh color, pink, light crimson, scarlet, dark crimson and purple; in form round, egg-shaped or elongated-oval; trees both upright and weeping, enormously productive, and in one or two cases the fruit, by hundreds of experts, has been pronounced the best plum in flavor of any in existence. Most of these selections are extremely productive.”
Wickson[128] reports that the roots of Subcordata have been used more or less as stocks for other plums but show no marked advantages over the species commonly used for this purpose. Most of those who have experimented with it condemn it as a stock because it dwarfs the cion and suckers badly.
Prunus oregana Greene[129] is from its description an interesting plum of which, however, it has been impossible to secure a glimpse even of herbarium material and of which we can therefore, only publish Greene’s description as follows:
“Evidently allied to P. subcordata, but leaves little more than an inch long, subcoriaceous, pubescent on both faces, in outline oval or broadly elliptic, never subcordate, commonly acutish at both ends, serrulate; flowers unknown; fruits in pairs or threes, on pedicels one-half inch long or more, densely tomentose when very young, more thinly so, yet distinctly tomentulose when half-grown.
“Known only from specimens collected on the Yanex Indian reservation in southeastern Oregon, by Mrs. Austin, in 1893; and a most remarkable species, as connecting true Prunus with Amygdalus. But that it is a plum and not an almond is evident.”