Who wouldn’t be excited to see multiple types of swallowtails and hummingbird moths, monarchs, butterflies and dozens of types of bees on a single shrub? Some plants tend to be specialists, but the bottlebrush buckeye, aesculus parviflora, is a real generalist showstopper, beginning in July. I am not aware of another plant that has such a wide variety of appeal to pollinators.
We live on a property large enough to host several Bottlebrush Buckeye. They can get quite large, around 12’ x 12’ (but can be pruned), and are a native to the USA, particularly in the southeast. They are tolerant of different soil types and prefer to be watered in periods of drought. They can be planted in full sun or part shade. We have some planted in heavy shade and they perform just as well, however, they are not as large as those in the sun. We use them mostly as an understory shrub but they could easily be used as a specimen shrub because of the pollinators they attract.
Right now, our bottlebrushes are roughly 6 feet wide, deep and tall. They are called bottlebrush buckeyes because the flowers resemble a very large brush, around 12 inches long, that would be used to clean out a wine bottle. Each bottlebrush has hundreds of small flowers on it to form a single bottlebrush. So there are plenty of flower heads to go around for all the various feeders…even hummingbirds.
The tiny green metallic bees may be one of my favorites to come to this shrub to feed. They are very small, about a third of an M and M (Covid snack food in this household!) with an entirely shiny head, thorax and abdomen. When not flying, their wings cover much of their metallic green bodies. These small bees are huge compared to some of the other even smaller varieties of bees that also pollinate this shrub. Remember, Wisconsin has over 400 different bee species. Having a shrub that attracts so many different pollinators is a great addition to any yard.
As beekeepers, we are thrilled to see our honeybees throughout all our bottlebrush buckeye. Knowing what makes the honeybees happy helps us to be more successful with honey harvesting. But seeing the wide range of insects is even more thrilling. We have seen hummingbirds in the shrubs, two variety of the clearwing sphinx moth or hummingbird moth, 6 different swallowtails, monarchs, silver spotted skippers, a variety of large bumblebees, honeybees, green metallic bees, black bees and bees I could not begin to name.
We have an area where we have three of these shrubs in a row. We are out investigating them at different times of the day just to see if the variety changes. So far we are thrilled with what this shrub adds to our overall garden. With bottlebrushes still forming, we have a long time to enjoy them. I cannot imagine not having this prize in our yard. If you plant one, I’m sure you will be impressed and thrilled with it as well. Be prepared to pull up a lawn chair to watch the non-social distancing pollinators!
To keep pollinators happy, consider planting shrubs and small trees that flower at different times so pollinators are kept busy on your property. It can only help your crops if you are also growing food. For early spring, some of my favorites are red buckeye, autumn splendor buckeye (both of these beloved by hummingbirds!), serviceberry (which also has tasty small fruit) and chokeberry (which has small fruit to feed the birds).
Late spring and early summer, I am a big fan of St. John's Wort 'Ames', a reliable well performing shrub that blooms July and August about the same time as the bottlebrush buckeye. I love it too for its small flowers that resemble buttercups. Kodiak Red honeysuckle (non invasive) is also a beloved pollinator shrub at this time of year.
Yet to bloom would be another favorite of mine and the pollinators, the seven sons tree. I can not say enough wonderful things about this shrub. It is just as popular as the bottlebrush buckeye but is at that all important time of the year when the days are getting shorter and pollen is in shorter supply. It is fragrant and such a joy to watch as all types of butterflies, bees and hummingbirds migrate to it in numbers.
The shrubs listed above in bold are still available at BGC at this writing. Also, we have all of these except the autumn splendor buckeye (but we have the similar Fort McNair) planted on our property and have been observing them for several years now. There are other shrubs that could be placed into this article but I am only writing about what I observe on my own property. Shrubs I know can take some abuse and still bloom prolifically!
One last clarification. On multiple occasions this spring, people asked me why something is called a tree yet it is multi stem, like the crabapple and seven sons tree by the pond at BGC. Many trees like crabapple and magnolias can be pruned to be trees but their natural habit is to be multi stem. Growers keep them single stem so they take up less room in the greenhouses. Makes sense. So if you do not want it to become more shrub in habit, you need to prune suckers. As for what makes something a tree vs a shrub in technical terms, a tree is over 20 feet and a shrub is under. But a tree can look like a shrub! There you have it.
Coming up in the next addition, perennials and annuals to support your pollinators.
Beth Martin is a BGC employee, Master Gardener, Master Composter, and Naturalist. All photos are taken by her.