Be aware that sunchokes/J-artichokes are rumored to be allelopathic. They are helianthus, just like sunflowers, which are definitely so. So might not be smart to plant them near something important.

Yes, you can top them. I don't recall them branching much if at all. I grew mine in the vegetable garden and noticed no inhibition of growth in the surrounding plants, other than what you'd expect from very tall, sun blocking plants. We had them growing in a flower bed in my childhood garden and they didn't appear to have any effect.

It would appear that there is more to this than rumor.

https://www.researchgate.net/publication/254214667_Allelopathic_Effects_of_Helianthus_Tuberosus_L_on_Germination_and_Seedling_Growth_of_Several_Crops_and_Weeds

The abstract strongly implies that they are, indeed, allelopathic. But you can do whatever you want.

I had some volunteer in the area where my leech field is, so I wouldn't eat them..I have been mowing them for at least 3 years and they still grow! I don't think much can hurt them. I have never dig them to see what the tubers look like, but they must be alive.

As for branching, I have never seen the ones in my eating patch branch.

So...does that mean that I shouldn't throw the leaves in the compost pile if the compost will be used on my vegetables? I never even though about it before!

That seems smart to keep them out of your compost. Other research says that the leaves and stems are somewhat poisonous to plants. Corn seems not to be affected, but tomatoes, lettuce, and squash have been shown to be hurt.

I've never had a problem using dead sunchoke leaves and stems in my compost. In fact, they are a welcomed yearly addition. The hollow stems add some bulk and help increase airflow in the pile. Can't comment on the growing plants being allelopathic as I keep them confined to their own raised bed away from the rest of my garden.

Also, the only time I have topped sunchokes was to deadhead spent blossoms in the fall. They didn't branch or grow any taller (but the aboveground part of the plants are finished growing at that point anyway). Topping during the growing season may have a different result.

Rodney

There are several research papers that bear on this. Here is one. "Residues", I think here means chopped and powdered dried leaves, stems, etc.

https://www.researchgate.net/publication/232693460_Potential_Allelopathic_Effects_of_Jerusalem_Artichoke_Helianthus_tuberosus_Leaf_Tissues

Potential Allelopathic Effects of Jerusalem Artichoke (Helianthus tuberosus) Leaf Tissues

From the abstract: "The simulated soil incorporation of different Jerusalem artichoke residues (four cultivars and a weedy population) was carried out in a series of laboratory and greenhouse experiments. Jerusalem artichoke reduced the radicle growth of seedling lettuce (60%), tomato (30%), large crabgrass (70%), and barnyardgrass (30%), whereas total germination of these species was less affected. Sensitivity to Jerusalem artichoke residues was species dependent; germination and initial growth of corn were not affected, whereas winter wheat, lettuce, tomato, rice, and zucchini seedlings were more sensitive to residue presence. Our experiments show that both wild and cultivated decomposing Jerusalem artichoke residues, particularly leaves and stems, possess phytotoxic potential."

So take it for what you will. Of course, it is possible that when composted, the phytoxicity goes away, but I don't know about that. I believe sunflower, eucalyptus and black walnut hot compost is not allelopathic, so it may work the same way.

I have never grown this plant, so I don’t know the size or girth of the stalks at season end. But, could it make sense to leave the trimmings on the ground within the patch of sunchokes to compost in place? I would bet they don’t effect their own growth, right?

I have sunchokes growing in my chicken run and they peck at the plants as they are growing and stunt their growth. They are still 4-5' tall though!

Some of my sunchokes are over eight feet tall already. They only get afternoon sun.