Will different species of elderberry get the same cross pollination benefits

Question

I recently planted a Lemon-Lace Elderberry (a Sambucus racemosa cultivar). Since I've read online that elderberries produce much more fruit if planted in multiples of different varieties, I'm looking for a mate for it. I'm planting in a very small yard though, and other varieties of S. racemosa grow very large - the other elderberry varieties that are described as small are all varieties of S. canadensis. I've only got room for a small bush. My question is, will S. racemosa cross-pollinate with small S. canadensis cultivars like "Ranch" or "Nova"? Or do I really need another red elderberry?

I'm planting the elderberries more for the birds than for myself, if that matters. And I'm in USDA hardiness zone 6b.

Answer 1

Well, it is a common refrain in the nursery business that you need two varieties to get fruit, and I am sure this increases sales but I'm not sure it is right. Many years ago I propagated one cutting into about 20 plants and every year the flowering heads are completely pollinated as the local birds can testify. Great for pies and wine and juice. Maybe I am just lucky with the variety I have, which is unknown to me, just that it has good fruit; or that I have a neighbour with a compatible variety which flowers at the same time.

I think really the advice might be better as "you need lots of flowers to attract lots of pollinators" since elderberry is at least partially self-fruitful and the more bees and other insects visiting the more the extensive heads can be covered. And of course the more bushes the more flowers. Fruit trees like pears produce small clusters of flowers producing large fruit, but elders produce large clusters with small fruit; it takes more time for a bee to cover the whole head.

The notion of "partially self fruitful" is an odd scientific statement. Either it is or it is not, one of the two.