I'm wondering if when the male does flower if you could clip a branch with flowers and take it to an area nursery to (1) get assistance from a nursery person to ID the male variety and (2) find suitable females that are also in flower at that time.

I have a couple of male plants and several females all within a one acre range. Some nurseries on the web tell you which male and female go together well, but I think ultimately it doesn't make much difference. I think they overlap in terms of pollen production. I hope this helps.

Thank you JohnFromPerryCoPA and GardenGranma for your replies. I noticed the first of the male's flowers today, the females are in bud.

JohnFromPerryCoPA- My experience has been that the nursery plants are not always flowering at the right time (unless the are local stock)or are too small to flower. I could try the local arboretum, though.

GardenGranma- I have never paid attention to the flowering times of my winterberries before since the female always produced fruit for the birds. But last year, the female did not have berries and I was interested in adding more females - so got interested in the flowering times. If this year's flowering times are typical (male is earlier than the female), then as you have observed for your plants, , there is enough overlap for my plants and I should be free to choose any female cultivar I want. I am interested in Red Sprite because of the size.