After the heat of the summer, when your perennials begin to look weathered and exhausted — or they're just falling over — it's time to grab your garden gloves and a spade to divide and solve the overcrowding problem.

Most perennials should be divided at some point. Often, your perennials need to be divided every two to three years. Otherwise, your blooms will be competing for nutrients and water and plants can outgrow their welcome. Many hardy perennials don't seem to skip a blooming beat once settled in a new location. Just fertilize regularly and add mulch when needed.

How do you know when to divide your blooms? Use this rule of thumb: If your perennials flower in spring and summer, fall is considered the ideal time to divide them. 

FOUR PERENNIALS TO DIVIDE IN THE FALL:

Sedum “Autumn Joy”: When there are so many blooms they are falling over it's time to divide. Once blooming is complete cut sedum to 6” above ground prior to dividing.  This allows for the plants to be more easily handled.  

Hosta: Divide Hosta after plentiful rain or a thorough watering the evening before so soil better adheres to the roots. September is a good month for most climates. Divide when Hosta look overcrowded in the space where planted.

Daylily: The best time to divide is when the clumps of stems provide fewer blooms throughout the season. Divide in late summer to early fall after the last flowering of the season. 

Siberian Iris: When the middle clumps stop producing blooms and the irises spread way beyond their boundaries, it's time to divide. Divide after the last bloom of the season.

There's nothing wrong with digging up these free perennials. Relocate the divided plant to a new spot or add them to a container in your garden. Dividing your plants is much easier than it seems and doesn't take much time. Who knew your landscape could produce so many more valuable plantings! 

In cooler regions such as Michigan, dig up the bulbs from plants such as Dahlias to store for the next season. Put peat moss in a ventilated box or bag, add the bulbs and move them to a dry place for safekeeping until you can plant them again.  

Next spring you'll be rewarded with new, more vigorous plants to share or add to your garden!