In the prairie Northwest considerable attention has been paid to Siberian crab-apples because of their superior hardiness and value for culinary use. Botanically considered, Siberian crabs are of two types: Pyrus baccata and P. prunifolia. The true Siberian crab (Pyrus baccata), according to Russian writers, has deciduous calyx segments (i.e., the segments fall off as the fruit ripens); in P. prunifolia the segments persist in the ripe fruit. Prof. L. H. Bailey has recently considered the crabs of the latter type to be hybrids of P. baccata with the common apple, P. Malus. Thomas Andrew Knight, a century ago, in England, produced several hybrids between the common apple and the pure Siberian crab, which proved specially valuable for cider. Since the introduction of the Siberian crabs into America they have been grown in apple orchards containing many varieties and have hybridized very freely with the common apple. There are now literally thousands of these crab hybrids, especially in the Northwestern States. Owing to the limited demand the distribution of many, even of the better ones, appears to be largely local. The Minnesota State Horticultural Society's recommended list of crabs and hybrids at present includes: Best for general cultivation: Virginia, Martha, Whitney, Early Strawberry, Minnesota, Sweet Russet, Gideon's No. 6, Brier Sweet. Promising for trial: Dartt, Pride of Minneapolis, Crampton's No. 3, Lyman's Prolific, Faribault.
The Northwestern market demands mainly bright red-colored varieties; for preserves the size must not be too large. For profit the trees must not be too subject to blight.
In recent years, in Iowa, attention has been drawn to large-fruited forms of the native crab as found at the West. So far the list of cultivated varieties includes Soulard, Kentucky Mammoth, Mercer and Howard, with some local sorts not yet generally introduced.
True long-winter-keeping quality has not been secured as a result of hybridization of the common apple with the Siberian crabs, and it is to be hoped that it will be obtained from these native American crabs. These native crabs all easily keep " till apples come again," and were formerly cached or buried in the earth for winter preservation by the Indians. At the present stage of development they will serve only for culinary purposes as a substitute for the quince. It is possible that the future winter apples of the Northwest will contain an infusion of the native crab of the Mississippi valley.
From the ornamental standpoint both the Siberian and native crabs have considerable value. The Siberian crabs as a class are much hardier, and will live and bear fruit much farther Northwest than the native crabs.
Fruit slightly below medium, ovate; surface greenish white, with yellow blush on sunny side; flesh crisp, spicy, rich, acid, good to very good. November to January.