How To Compost With Flowers: A Guide To Fall Clean Up

I enjoy cleaning up my flower and vegetable garden in the fall. By the time the end of the growing season approaches, my once tidy garden is rambling everywhere, and some plants are looking a bit ragged. While some plants can be overwintered, many will be removed and added to the compost bin.

What I do with my flowers at the end of the season depends on what type of flower they are.

Annual flowers can be cut down or pulled out of the garden at the end of the season since they will not grow back next year. Perennials should be cut back to allow for new growth in the spring. If possible, leave some flowers behind to feed and shelter wildlife through the winter.

A few general guidelines for flower clean-up will make this task easy and quick to perform in the fall. Keep reading, or put on this episode of my podcast, Organic Gardening For Beginners, to learn even more.

What should you do with garden flowers at the end of the season?

Annual flowers that will only live one growing season can be removed from the garden and composted or left in the garden to provide food and shelter to wildlife over the winter. Perennials will perform best if they are cut back

Annuals

Annual flowers only live one year. They start their growth in the spring, peak in the summer, and wind down by fall. No matter how long your growing season or how mild your winter, these flowers are genetically programmed to grow, bloom, and produce seeds quickly.

Some examples of true annuals that are common in home gardens are zinnias, sunflowers, and cosmos. Each of these will have peak growth and flower production in the summer time and early fall. By late fall they will start to slow down production and with the first frost, they will die back completely.

There are a few hardy annuals, such as calendulas, marigolds, and snapdragons, that can survive a light frost, but a hard frost or freeze will be the end of even those cold-tolerant flowers.

Once the flower plants slow down or stop blooming altogether, all you need to do is pull or cut the plant out of the ground and compost it. If you don’t have a compost bin at home, toss it in your municipal compost bin. If your city or town doesn’t have a composting program, then you can throw the dead plants in the garbage.

If the garbage is your only option, then I’d encourage you to leave as many flower plants behind as possible and wait until spring to remove them. That way you can help provide food and habitat to birds and bugs over the winter (more on that shortly).

Perennials

Tender perennials are often grown as annuals because they can only survive winter in warmer climates. If grown in colder areas that reach freezing temperatures or lower for long periods of time, tender perennials will die and not return in the spring.

Other perennials will easily survive a long winter and bounce right back come springtime and warmer weather. To know which type of perennial you’re growing, you’ll need to look it up.

Some common perennials grown in the home garden are lavender, echinacea, lupine, and Shasta daisies. For all of these flowers and other perennials, you’ll want to cut them back in the fall. You can wait until a frost has killed the leaves, then prune the plants down to about six inches above the soil.

You can follow the same guidance as you did for your annuals regarding the stems and leaves. Leave some in the garden for wildlife, or compost or throw away the plant debris.

If you haven’t yet planted a perennial garden, check out this article for some inspiration: Beginner’s Guide To Planning A Perennial Cut Flower Garden

Should all flowers be cut back in the fall?

Not all flowers need to be cut back in the fall, even annuals that won’t grow back the following year. Some flowering plants produce large seed heads that provide food to birds through the fall. Hibernating insects like ladybugs can also seek shelter in old flower plants left in the garden.

Some of the best flowers to leave in the garden at the end of the season are ones like sunflowers, rudbeckia, basil (technically an herb, I know, but herbs make great additions to the flower garden), and cosmos. They have long stalks that birds can perch on and large seeds that are easy to pick out and eat.

Perennials that are left behind will still return in the spring even if you didn’t cut them back. If the dead leaves at the base of the plant annoy you once fresh growth resumes in the spring, just remove it then and let the plant continue its new spring growth.

Long stalks and old seedheads can also look pretty when covered in frost, so leaving some annuals behind in the flower garden can add visual interest through the winter.

If you go this route, be sure to leave the plants until spring. Beneficial insects will likely use the plants as shelter over the winter, so wait until the weather starts to warm up and the bugs have become active again before removing the plant debris.

Can I compost dead flower plants?

Dead flower plants can be composted just as easily as food scraps or garden debris like leaves and grass clippings. The stems and root balls will take longer to break down, but the leaves and old flower blooms will quickly decompose, creating new organic matter for next year’s garden.

You can give the compost pile a jump start by chopping up the dead flower plants before adding them to the pile. The smaller the plant pieces, the faster they’ll break down because of more surface area for the bugs and bacteria to attack the material.

Here are a couple of ways to speed up the process:

• Cut thick stems into smaller pieces. Sunflower stalks, woody basil stems, and shrubby lavender are all great candidates.
• Use the lawnmower to do the chopping for you. Toss the dead flower plants on the lawn, run them over with the bag collector attached, then dump the shreds into the compost bin.
• Instead of pulling the plant out of the soil, cut the stem off at ground level. Leaving the rootball in the ground is a great, no-till practice. Worms, bugs, and other soil microorganisms will break it down and you can plant around it in the meantime.
• Read more about composting your flowers in this article, Can Flowers Be Used In Compost? Some Things To Keep In Mind.

If tilling is usually part of your fall clean-up, read here to see if it’s a chore that you can take off your list: Does A Garden Need To Be Tilled In The Fall? (Probably Not!)