Thank you for your response about the flowering crabapple. My question is when is the best and safest time to trim it? Also is it safe to cut the roots that popup (look like green bushes if you let them grow)
You can prune at any time. Pruning is often done in the winter because it is easier to see the structure of the tree without the leaves. You should not prune in the fall as the cuts will stimulate the tree to grow and make it more susceptible to winter injury if we have a severe winter. I generally tell people not to prune after Labor Day unless the tree is damaged in a storm.
Spring flowering trees and shrubs are often pruned after bloom as the flower buds are set in the summer. Remove any branches that are crowded in the tree to let light into the center. You can also remove branches that are in your way. You may want to remove some branches in the top of the tree to increase light penetration into the tree. This will also reduce diseases by increasing air flow through the tree.
Yes, you can cut off any shoots that emerge from the rootstock of the tree. It will not harm the tree. I would not recommend spraying them with an herbicide to kill tham as that will also harm the tree.