If you're a gardener in Minnesota, you may be wondering when it's time to divide your iris flowers. Generally, it's a good idea to divide them every three to five years. You'll know it's time to divide them when the group seems overgrown with weeds, the rhizomes start growing one inside the other, and they don't produce as many flowers. It's best to divide them when the plant is dormant, which usually happens in August.When the clusters of irises become too dense, it's time to use a garden fork and dig deep under the bully.
The buds of peonies are found underground and if they're too protected and deep, they won't get enough cooling and won't bloom.