Q.elderberries
I would like to grow elderberries, but I keep hearing that poison ivy usually grows with it. Is this true? If so, is there a way to prevent that? I have some family that are highly allergic to it.

Certified GKH Gardening Expert
I haven't heard about this association, but it's possible that some types of elderberry are found in the same habitat as poison ivy. In that case, growing elderberry at home shouldn't be a problem, since you'd be planting it intentionally. Just choose two varieties that are suited to your gardening zone and conditions:
https://www.gardeningknowhow.com/edible/fruits/elderberry/elderberry-bush-varieties.htm
If you see any poison ivy growing in your garden, you can remove it as described in this article:
https://www.gardeningknowhow.com/plant-problems/weeds/poison-ivy-control.htm