You shouldn’t assume that only iron “driven” deep into the soil will help stop the active growth of raspberries.
There are other, much more pleasant ways that will help limit the uncontrolled growth of this culture.
To do this, you will need to plant other plants along the raspberry bushes, and the first of them is sorrel.
This "gardener's assistant" secretes an acid that raspberries don't like.
The main thing is that the width of the sorrel bed is at least 50 cm, and the greens grow densely.
In addition, beans with their nodule bacteria on the roots have similar properties.
Here the scheme is somewhat different: the nitrogen released by the beans is spent by the raspberries on the active growth of green mass, thus being temporarily “distracted” from the idea of growing roots.
Finally, try surrounding the raspberry patch with a ring of marigolds - in this case, the raspberries will not only not spread throughout the entire area, but will also be protected from pests.
