Consulting the Horse Chestnut Oracle

[Nanohedron]

Got a wee volunteer horse chestnut sprouting in my back yard. They're handsome shade trees and I'd like to keep and cultivate this one, but my main concerns are two: First, the seeds, also called conkers. Do these pose much of a nuisance in yard cleanup? Second, disease vulnerability. It would appear that the horse chestnut can be prone to certain diseases, and I'm concerned about that.

Any information would be most welcome from those of you who have this tree and are familiar with it.

[chas]

I've never had any problems with diseases, but then I'm quite a distance from you.

As for the seeds, it all depends on what you consider a nuisance. The best part about them is their intermediate size. They're not so big that I mind hitting them with a lawnmower (or rake them up if you don't want to hit them). But they're also big enough that if you don't want them sprouting up everywhere, it's not too hard to pick them up in beds where you don't mow. (That is, they're not like acorns or ash seeds, which sprout up everywhere.) And they don't hurt to step on like beech nuts. I hate not being able to go outside barefoot.

[Nanohedron]

As for the seeds, it all depends on what you consider a nuisance.

Abundance, mostly. If they typically produce loads of nuts on their own no matter what, I'll be disinclined to keep it. If cross-pollination is needed, then I'll be less concerned because the nearest horse chestnut trees I know of are 5 blocks away (something like 1/4 mile, I believe). Which also raises the question of how that conker got in my yard.

[Mr.Gumby]

Abundance could become a problem when the tree matures. I have a horse chestnut we planted nearly twenty years ago and that doesn't present any problems yet. Leave the worry to a future generation.

There is a disease affecting horse chestnuts going around Europe. I don't know how much of a problem it is, there was a degree of worry about it a few years ago but I haven't read anything about it recently. I worry more about Ash die back, a fungal disease, that in a double whammy with a spreading parasitic beetle is expected to wipe Europe clean of ash in the coming decade, much like the Dutch elm disease did for the elm population.

[Nanohedron]

I worry more about Ash die back, a fungal disease, that in a double whammy with a spreading parasitic beetle is expected to wipe Europe clean of ash in the coming decade, much like the Dutch elm disease did for the elm population.

Here in the eastern half of the US and Canada we are trying to deal with the Emerald Ash Borer beetle. In its natural East Asian range it was just a nuisance, but since its introduction in Michigan only 14 years ago it has spread at alarming rates and people are concerned about the toll on ash populations. There are even billboards up warning about it. I take it this is the same beetle you mention?

We aren't facing Ash Dieback disease so far as I'm aware.

[Mr.Gumby]

I take it this is the same beetle you mention?

It is. Just forgot the name.

This is the latest article I read about it. It is a worry but specially so because around here along the coast of the Atlantic the ash is the only native tree able to survive the weather. There's oak in sheltered valleys and smaller hawthorn and imported pine plantations but ash is the main species at least in the strip along the coast. They're the backbone of our hedgerow that shelters whatever else we grow from the worst of the wind.

[Tunborough]

As for the seeds, it all depends on what you consider a nuisance.

Abundance, mostly.
...
Which also raises the question of how that conker got in my yard.

With our black walnut trees, both issues have the same answer: squirrels. Except in rare years of extreme abundance, the squirrels haul almost all of the nuts away for their own purposes. And some of them probably end up sprouting in a yard or field a surprising distance from the tree.

Even if you do have a rodential ground crew in your area, with a horse chestnut they are likely to leave behind the spiky shells, which could prove to be a nuisance, depending on how particular you are.

You might want to ask two more questions looking a few decades ahead: Is the shade going to fall where we want shade in the summer? Is an ice- or wind-storm going to bring down branches where we really don't want branches to fall?

[Nanohedron]

Even if you do have a rodential ground crew in your area, with a horse chestnut they are likely to leave behind the spiky shells, which could prove to be a nuisance, depending on how particular you are.

Squirrels and chipmunks we have, with the occasional wild turkey too. There isn't much if any human barefoot traffic there, so I figure the lawnmower could take care of the husks well enough.

You might want to ask two more questions looking a few decades ahead: Is the shade going to fall where we want shade in the summer? Is an ice- or wind-storm going to bring down branches where we really don't want branches to fall?

I've been considering this, too. The shade potential is very desirable, but the tree's proximity to the building and power lines when full grown is juuuust on the edge of a good gamble, closer than I'm comfortable with. I could shift it, but then it would eventually overhang cars in the parking lot and the shade to the building (the main factor in my wish to keep it) would be greatly diminished. I'm going to end up doing some harder measuring to account for future spread, because my eyeballing and guesswork isn't cutting it.

Now a buckeye has sprouted a few yards away, providing a perfect opportunity (for those who bother with such things) to mark the differences in their similarity.

[benhall.1]

The shade potential is very desirable, but the tree's proximity to the building and power lines when full grown is juuuust on the edge of a good gamble, closer than I'm comfortable with. I could shift it, but then it would eventually overhang cars in the parking lot and the shade to the building (the main factor in my wish to keep it) would be greatly diminished. I'm going to end up doing some harder measuring to account for future spread, because my eyeballing and guesswork isn't cutting it.

Horse chestnuts are not only huge trees - they regularly grow to 50ft high when planted as street trees here in the UK and grow to over a hundred foot when planted in open ground - but they are also fairly fast growing trees (though not the fastest). They can easily grow a couple of foot in both height and spread every year once they are established. Are you sure you want that near your house?

Now, buckeyes, depending on the particular variety, could be very much smaller. Personally, though, I'd rather buy a named variety where its future growth was reasonably predictable, than to rely on a stray seedling behaving itself.

[Nanohedron]

I'd rather buy a named variety where its future growth was reasonably predictable, than to rely on a stray seedling behaving itself.

And that's the thing, isn't it. Searching shows me that there's a heckuva lot of variation in horse chestnut habit according to cultivar. The more I think of it, the more it looks like I'll be getting rid of the thing. A shame, really; I've always liked those trees but never had one.

[benhall.1]

I'd rather buy a named variety where its future growth was reasonably predictable, than to rely on a stray seedling behaving itself.

And that's the thing, isn't it. Searching shows me that there's a heckuva lot of variation in horse chestnut habit according to cultivar. The more I think of it, the more it looks like I'll be getting rid of the thing. A shame, really; I've always liked those trees but never had one.

So get rid of that one, and look for a pretty, named cultivar - probably a hybrid between a horse chestnut and a buckeye* - that will grow nice and slowly and never get too big. A young tree shouldn't cost too much.



* Yes, I'm aware that some people use the terms interchangeably. I don't.

[Nanohedron]

Yes, I'm aware that some people use the terms [horse chestnut and buckeye] interchangeably. I don't.

Nor do I. Just like I don't call yellowjackets "bees". I've been called fussy before, if you can imagine it.

[benhall.1]

I don't call yellowjackets "bees".

That'd be "wasps" would it?

[Nanohedron]

Technically, yes. At a distance the yellowjacket can understandably be mistaken for a honeybee because of its size, coloring and short waist, but the behavior is totally different: Yellowjackets act like they're hard on a mission, and honeybees are like sleepy little shoppers. And I don't think I've ever seen a bee eat meat.

[benhall.1]

Technically, yes. At a distance the yellowjacket can understandably be mistaken for a honeybee because of its size, coloring and short waist, but the behavior is totally different: Yellowjackets act like they're hard on a mission, and honeybees are like sleepy little shoppers. And I don't think I've ever seen a bee eat meat.

Oh, I completely agree that wasps and bees are totally different. We don't have "yellowjackets" round these 'ere parts.