After planting numerous rounds of raspberries on 200 plots, this is what I found.

Ploughing - no problem.

Planting without either letting game finish ploughing or putting iPhone into sleep mode to force completion. The game crashed twice on first plot before allowing me to plant all 200.

However, if I ploughed and forced a completion, then collected animals or trees, or visited another neighbour then planting was ok with no crashes.