Certified GKH Gardening Expert
Yes, you can divide and transplant them just about any time, depending on your location. Grape hyacinths are quite hardy and take transplanting well as long as you provide the proper growing conditions and care. Here is an article that you may find helpful: https://www.gardeningknowhow.com/ornamental/bulbs/grape-hyacinth/planting-and-care-of-grape-hyacinths.htm You can minimize their spread by removing the foliage and any seed pods. This will keep seeds from being spread and weaken the bulbs so they cant produce bulblets.