This easy perennial has many varieties. The National Arboretum grows about 1,000 types and reports there are about 60,000 different types. The plant is so popular that gardeners nationwide have formed a society to focus their efforts to nurture these summer bloomers. You may have one or a few daylilies in your yard and want to know when dividing this perennial is optimal.
When fewer blooms occur
Last year your day lily was covered in blooms, but this year it is sort of sluggish. This is a sign that it is time to divide the plant into two or three sections. You can do it by digging up the entire plant with a spading fork, gently washing off the clumps of dirt and then using a screwdriver to gently pry the root and tuber tangle apart into sections. Alternately, you can separate the leaves halfway into the plant and using a clean spade push right through the root structure, dividing it in half or thirds. Using a spade will inevitably cut some of the root tubers in two. This does not damage the plant so long as two things are true. First, the spade must be clean, and not contain bacteria from infected plants that could contaminate the tubers. Second, the cut off roots must be quickly replaced in a freshly prepared flower bed, that has been amended with a full range fertilizer or compost.
Two or three years after initial planting
If you keep a garden journal, you can note that it has been two or three years since the daylily was planted, and to have the next year’s blooms be abundant, the plant needs to be divided. If you have no more room for another plant, put it in a container and give it to a friend, or a garden exchange. If you don’t keep a garden journal, you can look at the width of the plant. If your arms can get all around it as in a hug, it is probably one to two years old. If you need to spread your arms wide, like you are going to hug a baby elephant, it’s definitely time to separate the plant to give it breathing room.
When the blooming season is over.
Planting daylilies in the fall gives them a chance to start growing roots before winter. It usually makes sense to transplant perennials when they are not blooming. It may also help to prune their leaves so they are just eight or nine inches long.