Downtown tree in bloom an unexpected pleasure


Dr. Bob Gilbert – Columnist

Dr. Bob Gilbert

It amazing what you can find driving through our town.  The other day I spotted a fabulous blooming tree in front of a United Community Bank here in Franklin.  It is curious that I noticed it blooming this year as I have probably driven by it repeatedly over the 10 years that I have been here. I wonder if that is because we did not have a late frost this year so the blooms were not damaged?  This is an entirely new variety for me.  It was clear it is a Horse Chestnut evidenced but the shape of the bloom clusters called panicles or candles and by its palmate compound leaf arrangement with 5-7 leaflike structures or fingers.   I have seen horse chestnuts with white flower clusters but never pink to red.   Not too long ago I would have had to pore through numerous books and catalogs in order to identify it but a google search found it within a minute by simply matching blooms.  Not very scientific but it worked. 

 This tree is Aesculus x carnea or Red Horse Chestnut.  The x means it is a cross between two species.  In this case the species are Aesculus pavia-Red Buckeye and Aesculus hippocastanum-Common or European Horsechestnut.   The fact that carnea does not have single quotes means it is a hybrid as opposed to a “cultivar.” Hybrids can be produced repeatedly by hand pollination. A cultivar happens only once; the next time you cross pollinate you get something different.  Carnea means flesh like or pink referring to the bloom color.

Horse Chestnuts produce seeds or fruits similar to buckeyes.  The English call them conkers. The seeds are surrounded by a thick hull.  One falling on your head may, in fact, conk you out.   They really are not chestnuts and do not relate to our now almost extinct native chestnuts which belong to the genus Castanea.  They got their name by the misguided notion that horses when eating the fruit would get chest pain.  They are harmful to some animals when eaten.

It is not clear who made the first cross and introduced the Red Horse Chestnut.  It is speculated it was done by the Germans about 1880.   It did not take long before this tree became popular.  It grows to 30-40 feet and is spherical in shape.  It needs no special soil or care.  One report suggests that it does not thrive in very warm climates.    

There are some cultivars of the Red Chestnut.  A popular one is “Briotii.” It is a little smaller, more rounded in shape and has darker green leaves and also has similar blooms in late spring.  There are two other selections “O’Neil”  which tends to have double blooms and “Fort McNair’that has pink flowers with yellow throats.  These might be difficult to find.

It is not clear whether this tree is the hybrid Red Horse Chestnut of one of three cultivars.  Whichever selection we have here in Franklin we are lucky to have it.  Whoever the landscape designer was, he or she certainly had good taste. Keep a watch out for others.  I hope this tree is still in bloom when you read this.

Dr. Bob Gilbert, now living in Franklin is co-founder of Smith Gilbert Gardens in Kennesaw, Ga.

Karen Lawrence is a professional horticultural and wildlife photographer from Franklin.