White flowers on red buckeye

Question: My young (7 years?) red buckeye has had red flowers in past years. This year I’ve been waiting for it to bloom and thought I’d just missed it but maybe the long things that looked like stems of white buds were the spent red blooms about to become seed heads (because I certainly was not looking for a late-July white flower). Suddenly on return from vacation I find white inflorescences. What happened? How did it go from red flowers in past years to these white flowers this year? Thank you for any help.

responder: Answered by theHome and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied July 22, 2024, 11:41 AM EDT
response: Hmmm. That's unusual. The bloom time matches and the flowers look like those of Bottlebrush Buckeye (Aesculus parviflora), which you can see here:  https://plants.ces.ncsu.edu/plants/aesculus-parviflora/#:~:text=The%20shrub%20will%20grow%208,flowers%20with%20extruded%20red%20stamens. It is native to areas further south but does well here. We can only think that it either was seeded or had runner roots (this plant suckers with time) within your pot when you got the plant and has only now matured, or that maybe your red buckeye was grafted onto the roots of a bottlebrush buckeye. Can you trace the stems back to separate shoots rising from the soil around the base of the plant? With some researching it looks like red buckeye grow easily from seed so it's not likely that it was grown on bottlebrush rootstock.  It would be nice to have both, but the bottlebrush is a broad, suckering shrub that can form colonies over time which might not match what you have in mind for that area.   Christine

responder: The Question Asker Replied August 15, 2024, 12:32 PM EDT
response: Hi Christine and Ask Extension: Thank you for your thoughtful response. The other clue I had was that this year it seemed to me that the leafing out was a few inches in front of where I expected to find the small tree - and why are there multiple stalks instead of the one trunk that I protected from deer for many years. I think the answer, unlikely as it may seem, is that the red buckeye was a graft. At some point in the last year, probably in the fall,  something - either a limb from the overhanging black walnut, or my own fumbling - resulted in the trunk of the red buckeye breaking midway. There were no leaves left. I assumed that it would send out a new leader or branches from the single trunk this spring. Now I have this white buckeye and can find absolutely no trace of the original tree. Perhaps the remaining trunk was knocked over when I had the black walnut pruned of deadwood in late spring, and then cleaned up by the tree crew. In fact, as I write I recall that I had put pink tape on the remaining trunk as well as on other desirable plants...I didn't notice that it was gone after the tree work, I think it was still there...but it is gone now. Probably the tree company saw the broken trunk with no leaves, the pink tape, and thought that meant to remove it.(Sorry I did not recall all that prior to sending my initial question!)  So I am going with the graft idea, although there could have been seeds in the pot, dormant for these several years? (seems less likely to me.) Either way, I think I will remove the Bottlebrush Buckeye because such a space filler is going to be very awkward right there.    Thank you so much! Sorry it took me so long to acknowledge you. Now I'm going to go out one more time and hunt for any signs of the red buckeye having ever been there.       Just did that - no trace of it! Thanks again!   Susan

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied August 15, 2024, 1:32 PM EDT
response: You're welcome. Seeds of most plants can remain dormant for several years if conditions (like their depth in the soil) don't spur germination, but it's hard to guess if that's what happened here. As you noted, we can't rule-out that it was grafted either, though it might not matter much at this point.  Miri