 simply to the drip line of the tree as opposed to out farther which the roots go out farther we all know that but we may not be it sometimes happens when we have fertilized the lawn around the crape myrtle and there's not enough of a barrier area so mulch under the crape myrtle keep the grass away from it and also reduce the amount of nitrogen in the fertilizer that you're using which may mean keeping your lawn food a little bit further away from the tree usually that's how that turns out