How allelopathic is common hackberry?

I'd like to grow common hackberry (Celtis occidentalis), but recently came across some studies suggesting that it's quite allelopathic. Something I read even seemed to say that the effect is comparable to tree-of-heaven. Yikes... Hence my question to those of you more familiar with it: have you noticed any pronounced signs of allelopathy around C. occidentalis, or other Celtis species? What manages to grow underneath the trees, are there things that refuse to grow there? Other observations? Pictures of the understory under hackberry trees would also be brilliant, if you have any.

I've never heard of this before so I'll be very curious to see what others have to say.  

I don't have a picture right now, but my parents have an ornamental bed near a neighbor's fairly large hackberry.

There's a golden currant there plus some Virginia creeper, irises, phlox, and lots of northern sea oats grass.  They did plant a small Japanese maple that died quickly but I always thought it was because it's dry as well. (There's a large sliver maple nearby too so when any kind of drought strikes, everything goes bone dry.)

Oh, and the soil is sandy.  It's just a harsh place.  Also, their vegetable garden is another twenty feet farther out and that side of the garden is maybe less productive, but again I always assumed it was the shade and roots.  I'll try and remember to take a picture some time.

We had hackberry trees at our former residence, where Our daughter lives.

Both of us have had huge gardens every summer.

Maybe keeping the leaves rake up and out of the garden is the key to success?

I am just curious why you want to plant hackberry?

I have had a northern hackberry tree planted in my chicken run for about 10 years now. I was not aware of it being allelopathic, so have not been on the lookout for it. Growing under and near it are a variety of weeds that the chickens keep trimmed, along with many new Hackberry trees that sprout up from the roots. A couple autumn olive cultivars are doing well near this tree. I also have a couple Celtis sinensis, Japaneese Hackberry trees of the same age planted from seed. These are in a lawn setting so I have noticed no problems with other plants growing near them, but they do seem to have shaded out the fescue. I also have a few Celtis laevigata, Southern hackberry/sugarberry trees. One has many tiger lilies thriving under it, and another has gooseberries, and viburnums growing close by. If you want the fruits and nuts from a hackberry tree, I am getting the best harvest from Celtis australis, the Euorpoean or Himilayan hackberry, aka. Nettletree. These have slightly larger fruits, and so far I have detected no negative allelopathic effects from them either, but will be looking closer for such things this summer, than I have been in the past.

Thank you all for reassuring me. If you haven't noticed anything, the effect is probably not extremely strong at least. Also, most reports about hackberry allelopathy and invasivity that I could find are from Hungary, and Hungary seems to have a very hard stance on "invasive" species...

As to why I want to grow hackberry, it's because I read this article.

Akiva Silver wrote:  Hackberries have a thin, very sweet purple skin surrounding a crunchy shell with a tiny nut inside. All hackberries are edible and highly nutritious. They have been consumed by humans for millennia and are one of the first known foods that humans have eaten and stored. Caches of hackberries have been found in ancient cave sites. It is no wonder that early people were eating hackberries. They are high in fat, protein, carbohydrates, and vitamins. Hackberries are almost like a hybrid between a nut and a berry. They are a versatile, power packed food.

   Flavor will vary from tree to tree, but in general they are sweet, tasty, and crunchy. Some are thin shelled and have the consistency of a peanut m&m, others are much harder. They can be so crunchy at times that it is hard to chew them. This crunchiness is best overcome with a little processing. Smash the berries in a mortar and pestle or with a couple blocks of wood. The more crushed up, the better. You can then take the mash and form it into any shape. It will keep quite well stored at room temperature and makes an excellent trail food.

This sounds awesome to me, especially since I live in a climate where we can't grow so many species of nuts (and I love nuts!) Its hardiness is also the reason for wanting to grow Celtis occidentalis rather than C. australis. Both might work, since we're formally in USDA zone 6, where occidentalis is hardy to zone 3 and australis to zone 5, but since the USDA system is a bit limited and designed for a continental climate rather than our very oceanic one, there are many plants that should work according to the USDA, but in reality absolutely do not. I figure it's best to start with the hardiest one, and then if it grows really well maybe try C. australis later.

I also planted mine for the fruits, figuring if I did not care for them, the other wildlife certainly would, but I do quite enjoy them. Of the four Celtis varieties I have planted, only the australis has fruited for me so far, and it was the last type I planted. I was also concerned about Celtis australis not being hardy in my area. Apparently it is a wide ranging species, where some phenotypes originating in warmer areas will not be as hardy as seed sourced from trees in colder regions. Mine came from Oikos Tee Crops in Michigan, and has grown well here in Maryland.