Perimeter plantings of crabapples would provide a large number of trees and should be designed so the trees can still be sprayed for pests and diseases. There are many creative options available to the innovative grower that can both increase productivity and beauty of the orchard with the use of crabapples. With the new concept of pollen transfer in the beehive a major component of pollen distribution in the orchard, the main idea with crabs, or with any pollenizer for that matter, is to have a sufficient number of them so there is a large volume of compatible pollen available when the cultivars to be pollinated are in bloom. There is no fixed figure on the appropriate number of pollenizers to have for any cultivar. The smaller the percentage of crab trees relative to apple trees, the more dependent the grower becomes on the satisfactory annual performance of each pollenizer tree.
Most crabapples exhibit some degree of bienniality in flowering.
This characteristic is one reason for using several crab cultivars in the pollenizer planting rather than relying on only one crab cultivar to do the entire job. The whole purpose of having crab trees is to obtain annual, heavy bloom. Mixing several crabapple cultivars reduces the likelihood of insufficient bloom. It is extremely important for growers to understand as much as possible about which crabs are biennial and which are more nearly annual. Experience is lacking in managing cropping in crabapples to overcome bienniality.