I have an Old German heirloom tomato plant that is growing out of control. I started it out in a regular 4' tomato cage which it quickly outgrew. I left it in the cage and constructed a tipi out of bamboo and twine for The Monster Plant. It now has filled the tipi and is over 8 feet tall. I can't reach anywhere near the top and the plant is giving no indication of slowing down. It's not setting much fruit.

If I pinch off the tallest growth tips will that encourage the plant to set fruit and stop growing?

My other tomato plants are all a manageable size (under 6 feet). Has anyone experienced this kind of growth with the Old German tomato?

I fertilize with a low nitrogen tomato-specific fertilizer every other week and water deeply with a soaker hose as needed.

Thanks!!