The Very Best Timing For Dividing Perennials In Fall

Perennials are often the go-to plant type for thrifty gardeners. After all, you can buy one plant, and with proper care, it can last a lifetime. Savvy gardeners often maximize their investment by dividing perennials to propagate more plants. Another reason gardeners might want to do this is to improve the overall health of the plant. One of the most important things you need to know before dividing your perennials is the proper time to do it. The best time to divide perennials in the fall is four to six weeks before your first frost date.

There are many perennials that benefit from being divided in the fall. Some great examples include sunflowers (Helianthus annuus), daylilies (Hemerocallis), Black-eyed Susans (Rudbeckia hirta), and hostas (Hosta plataginea). On the other hand, there are some perennials that you should avoid dividing at all costs, like lavender, baby's breath, and rosemary, to name just a few.

If your plant benefits from fall division, all you need is a suitable planting location and knowledge of your last frost date. You can check this by using the Old Farmer's Almanac frost date checker and then counting four to six weeks before the date shown. Dividing your perennials during this period will give the plants time to establish and promote healthy blooms in the spring and summer.

Whether you're dividing your hostas this fall for a healthier plant or your Black-eyed Susans for more blooms, you need to follow a couple of steps. Ideally, your division time frame is when there is some overcast weather. You don't want it to be too sunny or warm. That's why fall is the ideal time for perennial division. You should also make sure you water the area around your perennial the day before you divide. This will ensure your soil is easier to work with.

Once you've prepped your plant, dig about six inches around it, so you don't damage the main roots. Gently lift the plant out and brush any excess dirt off the root system. For tougher root systems, it's best to use sharp tools to carefully divide them into separate plants. Each new division should have at least three, but ideally five, shoots and a healthy root system of its own. Plant each division in a hole slightly larger than its root ball.

Make sure you are planting in a well-draining area. Place the plant in the hole, cover with soil up to the crown's base, and gently pack the soil. You will want to water regularly, but do not over-saturate, as this can lead to root rot. Dividing perennials four to six weeks before the first frost allows roots to establish before winter.