This type of dogwood is called Cornus stolonifera and also comes in a red twig form. It can be cut back all the way to the ground in early spring so don't be shy. If it is growing too wide you may need to dig out the roots that grow sideways. It will keep stealing real estate as long as it lives so perhaps a barricade under the soil like a fiberglass wall will contain those aggressive underground roots. Keep growing, Marianne Binetti