Label

<date-picker v-model="start" label="START" />
<date-picker v-model="end" :disabled="!start" :min="start">
  <div slot="label">
    <span style="font-size: 20px">«</span>
    <span>END</span>
    <span style="font-size: 20px">»</span>
  </div>
</date-picker>

export default {
 data() {
   return {
     start: '',
     end: '',
   }
  }
}