While pruning may seem counterintuitive for your beloved perennials, cutting them back in the fall can actually have numerous benefits. It boosts plant health, enhances yields or flowering, and even promotes future growth. However, it’s crucial not to prune every perennial species indiscriminately. In fact, some plants are more vulnerable than others, with improper pruning potentially hindering next year’s harvest or blooms.
To make the most of your fall pruning, it’s essential to understand which perennials require trimming and how best to do so.
Why is it Important to Cut Back Perennials?
While pruning perennials isn’t essential, it’s crucial for their well-being and your garden’s aesthetic appeal. As these plants regrow year after year, they shed old growth, foliage, and spent blooms, leaving behind decaying debris that can harbor disease and infect the plant at its root level. To keep your perennials healthy and thriving, it’s essential to trim them back regularly.
This not only maintains their appearance but also prevents the accumulation of rotting matter that can harm the plant. To prune effectively, you’ll need a few tools: clean, sharp garden snips or pruning shears, rubbing alcohol wipes or a bleach solution for cleaning your equipment as you work, gardening gloves to protect your skin from sap and other irritants, and a basket or pail to collect the removed debris for composting or disposal.
Vegetables and Edible Flowers
To ensure optimal growth and flowering for certain edible perennials, it’s crucial to prune or cut them back before winter sets in. By doing so, you’ll be giving these plants the necessary boost they need to come back stronger and healthier next spring.
Daylilies
Daylilies (Hemerocallis spp.) thrive annually after being cut back in the fall. Following their mid-September bloom, trim them down to about two inches above soil level. To ensure a healthy start come spring, apply a layer of mulch for winter protection. This simple step will have your daylilies bursting forth with new life when warm weather returns.
Bronze Fennel
Foeniculum vulgare, also known as wild fennel or sweet anise, serves a dual purpose in gardening – its ornamental value and edible uses make it a prized addition to many landscapes. Interestingly, this versatile plant is also a vital food source for swallowtail butterfly caterpillars. While these larvae can be voracious eaters, stripping the plant bare by autumn, pruning the fennel back to soil level can help control their appetite, ensuring a healthier and more sustainable growth cycle.
Hostas
When the first frost hits, don’t let your hostas (Hosta spp.) go to waste. Yes, you read that right – hostas are edible! However, before you start snacking, make sure to prune them back to about 6 inches above soil level. This will help keep the plants healthy and encourage new growth in the spring. Additionally, remove any fallen debris from around the plants. You can compost this material, burn it, or bag it up for local yard waste collection.
By taking a little time to tidy up your hostas, you’ll be helping to prevent the spread of disease and keeping your garden looking its best.
Chrysanthemums
While many people cultivate chrysanthemums for their ornamental value, these plants also have a culinary side. In fact, certain varieties like Chrysanthemum morifolium and Chrysanthemum indicum are cultivated specifically for tea production, where they add a fragrant and delicious flavor. Moreover, garland chrysanthemum greens (Chrysanthemum coronaria) are a popular ingredient in many Asian dishes.
Regardless of the specific variety you’re growing, it’s essential to prune them back to around 5 or 6 inches above soil level after harvesting, followed by mulching around their roots to protect them from winter’s frost.
Perennial Sunflowers
While most sunflowers have a relatively short lifespan as annuals, certain varieties like Helianthus x laetiflorus and H. salicifolium exhibit remarkable persistence, surviving year after year. Following the harvesting of their seeds, the stalks’ towering presence may appear to persist, only to attract unwanted insects seeking winter shelter. To prevent this, it’s essential to reduce the canes to soil level, either through composting or burning them.
For those with a green thumb and sturdy canes, an innovative approach could be using them as natural fish basket traps – a creative way to minimize waste while cultivating resourcefulness.
Jerusalem Artichokes
Sunchokes (Helianthus tuberosus) bear a striking resemblance to their sunflower cousins in terms of growth habit. The towering stalks that support their bright yellow flowers require pruning after the growing season has concluded, with the top growth cut back to soil level. This allows for the harvesting of their starchy roots, which can be transformed into delectable soups and roasts.
In order to prepare the sunchokes for the next year’s growth, any remaining plant material should be either burned or composted. Additionally, it’s a good idea to mulch the root areas with straw to provide insulation and protect them from the elements over winter.
Medicinal and Culinary Herbs and Flowers
It’s a common oversight, but many gardeners neglect to prune their perennial herbs, such as oregano and chives. However, doing so can have a significant impact on the health and productivity of these plants. By giving your oregano and chives a good haircut, you’ll be providing them with the necessary guidance to thrive.
Bee Balm
These stunning flowers, belonging to the Monarda spp. species, are renowned for drawing in hummingbirds, butterflies, bees, and other native pollinators. Beyond their ornamental appeal, these plants possess remarkable medicinal properties, making them a crucial addition to any self-sustaining healing garden. Once you’ve harvested your bounty, be sure to cut the stems right down to soil level to promote healthy regrowth.
If any stems exhibit signs of mildew, it’s essential to incinerate them rather than incorporating them into your compost pile. This precautionary measure prevents the pathogen from spreading during the winter months. Following proper harvesting and stem care, treat the surrounding soil with an organic fungicide to ensure a healthy start for your plants in the seasons to come.
Catnip
Nepeta cataria, a charming member of the mint family, thrives when pruned back to approximately 2 inches from soil level before the onset of winter’s first frost. Failing to do so can lead to the fleshy leaves and any remaining flowers succumbing to an unappealing decay, as they are vulnerable to cold damage.
Oregano
Oregano (Origanum vulgare), a herb known for its hardiness and ability to thrive under moderate conditions, requires a unique approach when it comes to pruning. Unlike its more delicate cousin, catnip, oregano does best when trimmed back aggressively before the onset of autumn. This technique allows the plant to maintain its potency and aroma, which would otherwise be significantly reduced after flowering.
Once the bees have completed their harvest, cut the stem back to approximately 2 inches above soil level to promote healthy growth. Interestingly, mulching is only necessary for growers in zones 3 and below, as oregano is naturally well-equipped to handle frost and other harsh conditions.
Chives
Savoring the flavor of chives (Allium schoenoprasum), these versatile alliums thrive throughout the summer months. The vibrant pink blooms can be used to add a pop of color and subtle garlic essence to salads, soups, and other dishes. As the season progresses, the tube-like leaves become perfect for chopping into omelets, baked potatoes, and other culinary creations. When autumn’s first frost arrives, simply cut back the entire plant to soil level, allowing it to regrow come springtime.
Yarrow
Yarrow (Achillea millefolium) is a potent healing ally that requires some maintenance to keep it thriving. After harvesting its stems and flowers, it’s essential to cut the entire plant down to soil level if there are any remaining parts. Rather than leaving them to decay, compost or burn them to prevent the spread of disease. This hardy herb has an impressive ability to regrow abundantly in the following season, making it a great addition to any garden.
Peonies
While peonies (Paeonia sp.) are often categorized as ornamental plants, many herbalists cultivate various species for their medicinal properties. However, these lovely flowers do require some attention to thrive. In the fall, when the weather is cool and damp, they can be prone to mildew development. To prevent this issue, make sure to tidy up your peonies once you’ve harvested what you need.
After the foliage starts to turn yellow-gold, cut back the plants about a week later, leaving only two or three inches above the soil surface. If you live in an area with harsh winters, consider covering the base of the plant with mulch for added protection. This simple step will help your peonies emerge in great shape when the weather warms up again come spring.
Decorative Plants
When pruning season arrives, don’t neglect to tidy up your ornamental perennials. Not only will this maintain a visually appealing landscape, but it can also have the added benefit of promoting healthier growth and potentially more vibrant displays come spring.
Hollyhocks
When cultivating hollyhocks (Malva alcea) in your outdoor space, one of the most crucial steps in maintaining these lovely flowers is properly pruning them after they’ve reached the end of their blooming cycle. As you’re likely familiar with just how tall hollyhocks can grow, it’s understandable that the aftermath might look a bit peculiar. To keep them looking their best and promote healthy growth for seasons to come, be sure to cut them back to ground level.
Additionally, consider applying a layer of mulch around their base if you reside in USDA Hardiness Zones 5 or below.
Ground Clematis
Clematis recta unfurls its vibrant beauty across the landscape during the summer months, painting the scene with bold strokes of color. However, as the seasons transition and winter’s chill sets in, this charming flower undergoes a remarkable transformation, surrendering its petals to form a rich, nutrient-dense compost.
To encourage healthy regrowth in the spring, it’s essential to prune the stems back to soil level once they’ve finished blooming, allowing the plant to conserve energy and redirect its focus towards new growth.
Painted Daisies
Transform your garden with the vibrant beauty of painted daisies (Tanacetum coccineum), which burst forth with glorious splashes of color from mid-summer through to late autumn. As their blooming period comes to a close, the stems may turn a dull blackish brown, but don’t be deterred! Simply prune them down to about 3 inches above soil level and allow them to rest. Come springtime, they’ll regrow with renewed vigor, ready to once again delight your senses.
Bearded Irises
When the blooming cycle of water-loving irises (Iris germanica) comes to an end, they undergo a transformation that’s anything but appealing. The once-vibrant plants become slimy and dark, a sign that their energy is shifting from growth to decay. To make matters worse, they can fall prey to various fungal pathogens and cane-boring insects that take advantage of the plant’s weakened state.
To prevent the spread of disease and encourage new growth, it’s essential to cut these irises down to their roots as soon as their flowers start to wilt. Dispose of the cuttings by burning or discarding them to ensure a healthy start for the next growing season.
Notes on How to Cut Back Your Plants in the Fall
When it comes to pruning perennial plants, proper tool hygiene is crucial to prevent the spread of pathogens. Make sure you’re using clean, sterilized shears or snips at all times, and give them a quick wipe-down with an alcohol swab after cutting each species. This may seem like an added hassle, but it’s essential for maintaining the health of your plants. Not all perennials require pruning in the fall, however.
Some, like decorative alliums, echinacea, and goldenrod, produce valuable seed heads that provide sustenance for birds during the winter months. These seed-bearing species should be left intact to allow for seed production, then cut back in the spring to encourage new growth. Before pruning your perennials, take the time to research whether they’re best pruned in the spring or fall. Some plants are sensitive to cold and require their foliage to remain intact over the winter months.
This consideration will help you provide the best possible environment for your plants.
