Gardeners Corner Fall 2022

Grassy weeds becoming more common in lawns

By Horticulture Educator Chris Enroth

When confronted with lawn weeds, typically we think of dandelion, creeping Charlie, and violet. These plants and many others are classified as broadleaved weeds, or dicots, and are easily distinguished from grasses which are monocots. Scientists have engineered herbicides that target broadleaved plants, while the chemical does not affect desirable turfgrass.

But what happens when you have a grassy weed appear in your lawn? Selective lawn herbicides containing 2, 4-D or dicamba, are useful in controlling broadleaves, but will not work on grasses.

Photo by Chris Enroth. Perennial grassy weeds like quackgrass or nimblewill are becoming more common in home lawns.

Annual grasses, such as crabgrass are best controlled with a preemergent herbicide applied before the offending weeds germinate. Once the seed has germinated a homeowner should practice good lawn care culture that can make a lawn more competitive with the weeds.

Perennial grassy weeds like quackgrass or nimblewill are becoming more common in home lawns. They are difficult to control because they are perennial, meaning they come back year after year.

And since cool-season grassy weeds, like tall fescue, match the lifecycle of our desirable cool-season turfgrass species this makes it difficult to find a targeted timeframe or chemical that will kill the offending plant, but leave the desirable turfgrass. Often homeowners must resort to spraying a non-selective herbicide, such as glyphosate, rake out the dead patch and reseed with their desired species of turf.

Enroth says lawn herbicides containing mesotrione have shown to be effective at controlling some troublesome grassy weeds like nimblewill. But other products are a bit pricey and best left to professional lawn care companies. And most can only legally be used by licensed applicators.

I do not spray herbicides on my lawn. I practice good lawn culture, which gets me about 80% of the way to a perfect lawn. The other 20% is easy to live with.

With this approach, I look for established vegetation. A successful lawn has a groundcover that won’t erode and send sediment into the streams and rivers, plus the plants must tolerate family activities. The benefit of weeds is that they are still green. The added benefit of weedy grasses is that at least they blend in, more or less, with the turf.

Proper lawn care practices

Mow high – Set the blade to almost the highest setting (3½ inches). Cool season grasses, like turf-type tall fescue, prefer this height.
Sharpen blades – Getting a mower’s blades sharpened can make a world of difference and will cut your lawn instead of beating up the lawn with a dull blade.
Avoid high amounts of nitrogen in the early spring. The grass grows fast enough at that time of year. If you will only fertilize once, opt for the late summer to early fall for cool-season lawns.
Overseed from late summer to early fall.
Keep it clean. Pick up after pets.
Stay on top of mowing. Avoid removing more the 1/3 of the leaf blade to not stress the lawn.

For more information on lawn care, connect with your local Illinois Extension county office at go.illinois.edu/ExtensionOffice.

Gardener's Corner is a quarterly newsletter from the Illinois Extension team of horticulture experts. Each issue highlights best practices that will make your houseplants, landscape or garden shine in any season. Join the Gardener’s Corner email list for direct access to timely tips!

Keep garden, plants hydrated going into fall

By Horticulture Educator Andrew Holsinger

This summer has brought drought to many parts of Illinois. Most gardeners are aware that plants need water to thrive, but it can be helpful to review the ins and outs of garden hydration to ensure the best results.

Many environmental conditions factor into plant survival. Hydration is one of the most important of those factors.

Plants vary in their moisture requirements, but as a general rule, vegetable crops require at least 1 inch of water per week. Excessively hot or windy days lead to a need for more frequent irrigation because more water is lost from the plant. Too little water can cause not only drought stress but also increased disease or insect susceptibility.

The most straightforward way to identify drought is to look for the impacts such as on plants. Sometimes these impacts may go unnoticed, especially with trees and shrubs. Water is especially important in the fall for evergreen trees and shrubs as these plants still lose water even during the winter.

Mulch can help conserve moisture and reduce the plant’s demand for more water. For plastic mulches, the plants will need to be irrigated regardless of rainfall events. Water does not readily penetrate beneath the plastic, so it is often necessary to add drip irrigation under the plastic.

Putting moisture in the right place, where the plant is located, is also a way to reduce weeds because you’re not providing water where it isn’t necessary.

It’s not advised to water mid-day during hot periods as more water is lost to evaporation. Morning is usually the best time to water as it allows for the foliage to dry preventing fungal diseases caused by leaves that have remained wet for too long.

Drip irrigation delivers water to the base of the plant instead of on its foliage. Gardeners should avoid excessive water application on leaves to avoid fungal pathogens and diseases, some of which can cause wilting. Surprisingly, overwatering can also cause wilting, so be sure to check the soil before watering.

For most plants in the garden or landscape, a well-drained soil is required. However, in some spaces where drainage may be an issue, a raised bed can help increase drainage. Raised beds can be used for both ornamental and edible crop plantings.

Containers can be great for growing, but they need adequate drainage holes. A more frequent watering schedule is required for containers, as they dry out more quickly than garden beds.

It’s rare in Illinois to see consistent precipitation throughout the season, and an attentive gardener is aware of it. Your watering schedule will have to be adjusted over the season.

As plants mature, they require more water. Therefore, if you have a limited amount of water available to dedicate to your garden, you may want to plan ahead. Setting up zones based on water use can help to distribute water at appropriate levels to plants based on their cultural requirements.

For more information on plant care, connect with your local Illinois Extension county office at go.illinois.edu/ExtensionOffice.

Extend the season with fall flowers for your beds, borders, and containers

By Horticulture Educator Brittnay Haag

Fall blooming plants extend the season of our gardens after many plants have dried up or are done blooming for the year. They are also a much-needed food source for pollinators who are still foraging and getting ready for winter.

Prolong the floral show in your yard with annual or perennial plants that bloom late summer into fall.

When designing the garden, aim to have plants blooming continuously from spring to fall, using a variety of plant species. Perennials can be planted now, but make sure to allow at least four weeks for the roots to develop before a hard frost arrives.

If you don’t get to it this year, make plans for next year. Perennial plants can also be planted in the spring or early summer.

Black-eyed Susan (Rudbeckia hirta) is a native perennial with late-season blooms to add to your garden.

Perennials with late-season blooms

Helenium (Helenium autumnale L. var. autumnale)
Joe Pye weed (Eutrochium purpureum)
New England aster (Symphyotrichum novae-angliae)
Black-eyed Susan (Rudbeckia hirta),
Sedums (Sedum sp.),
Japanese anemone (Eriocapitella hupehensis).
Shrubs: Rose of Sharon (Hibiscus syriacus), panicled hydrangea (Hydrangea paniculata), or Bluebeard (Caryopteris x clandonensis).

Annual plants, those completing their lifecycle in one year, can offer colorful blooms from spring until frost. Consider sprucing up your overgrown or spent-looking summer containers with a fall makeover to create a beautiful display of warm, autumnal colors.

Combine some fall blooms or foliage with existing plants that still look healthy and are blooming. Many thriller plants or focal plants such as ornamental grasses and tropicals will look great through the fall. They will add structure and height to the arrangement since many of your newly planted annuals will be shorter.

If you plan to overwinter any of your tropical plants indoors, make sure to transplant them to a different container and move them indoors before temperatures drop below freezing.

Pansies (Viola sp.) can be added for a bright pop of color in any container and will have a long and late blooming season. They will do best in partly shaded areas and regular waterings. Ornamental kale and cabbage (Brassica oleracea) create a rosette of colorful and interesting foliage mixed with blooming plants. Find varieties with combinations of greens, purple and white to add to your full-sun containers. Swiss chard ‘Bright Lights’ (Beta vulgaris) is typically grown as an edible, but it is too beautiful to not include in decorative fall containers. The combination of rainbow-colored stems and glossy green foliage almost makes it look artificial.

To make your fall containers last longer, cover them with light blankets or larger containers when nighttime temperatures are below freezing. Many of the annual plants at the garden centers this time of year will survive in temperatures as low as 20°F without any damage.

For more information on plant selection or care, connect with your local Illinois Extension county office at go.illinois.edu/ExtensionOffice.

Stretch out the growing season with fall planted salad greens

By Horticulture Educator Nancy Kreith

When people think of fall, harvesting salad greens rarely comes to mind. However, late summer is a terrific time for gardeners to begin planting lettuce, arugula, endive, or other leafy greens for salads. Not only are these plants quick and easy to grow as temperatures start to cool, but they also add a significant source of nutrients to your diet.

Most leafy greens are rich in vitamins A and C, potassium, calcium, and fiber, and are low in calories. Studies have shown lettuce to have high antioxidant compounds – red leaf being the highest – that help to fight certain types of cancer.

When growing salad greens, transplants are not as easy to come by in late summer as they are in the spring. The best option may be to plant seed directly into the garden bed. Transplants can be set into the ground in early to mid-September and seeds should be planted in late August to early September. Refer to seed packets for specific planting dates for your region. Direct seeding is a great method for most salad greens, considering many will go from seed to harvest in less than 45 days.

Whether planting seeds or transplants, loosen the soil first, add all-purpose granulated organic or synthetic fertilizer, plant, and water. For transplants, carefully spread out the roots, place the plant into a hole, and lightly firm up the soil around the base of the plant.

For seed, dig a shallow trench, add a pinch of seed along the row, and lightly cover it. Be sure not to plant seeds too deep. A general rule of thumb is to plant a seed two to three times its thickness underground. Keep seeds evenly moist with a light sprinkle of water every other day until they germinate, usually in about a week. Typically, most direct-seeded salad greens will not need to be thinned.

Gardeners should think about what types of greens will suit their tastes when choosing what to plant.

Common salad greens

Green leaf lettuce is known for its mild flavor and grows in a loose bunch.
Red leaf lettuce adds color to your diet, is rich in antioxidants, and has a shorter shelf life.
Butterhead (bib or Boston) lettuce grows into a soft head with tender, rounded leaves and is known for its mild, buttery flavor.
Arugula grows very fast and is often harvested as baby leaves. It has a distinctive peppery flavor and is quite pungent. Harvest this green before it becomes overgrown and hairy.
Mizuna is tangy, not as tender as most greens, and will add texture to salads with its deeply cut fringed leaves.
Japanese red mustard has a sharp flavor with notes of pepper, garlic, and mustard. It should be harvested as baby leaves for use in salads. Larger leaves are commonly used in stir-fry dishes.
Baby bok choy has a mild, refreshing flavor and crunchy, celery-like texture. The outer, more mature leaves of this green can be harvested as needed or wait until the loose head has matured and cut the entire plant at the base.
Belgian endive is pale yellow and has a dense, long head of crunchy leaves. It can be added to salads but often is used for wraps or other appetizers.
Curly endive (frisee) has beautiful, frilly, yellowish-green leaves with a strong, somewhat bitter taste.

Once salad green varieties are selected, sourced, and planted, follow the best practices for post-planting care. Provide plants with at least 1 inch of water per week. Plants should not need another round of fertilizer with good quality soil. Remove weeds and consider mulching the soil with straw or untreated grass clippings. Monitor plants and harvest them as leaves mature or as needed depending on the type.

It is important to have a plan for harvesting, as greens can quickly become overgrown and result in a tough texture and bitter taste.

For continued harvest, cut the outer leaves first and keep the central point growing. Baby leaves can be harvested, clear cut, as the plant grows and are tender and tasty. Plants will grow back for another round of harvesting after being clear cut. Leaves can be rinsed in cold water before serving and pat dry with a clean towel.

If a bulk supply of greens are ready to harvest, cut and store them in the refrigerator rather than letting them over-mature. Lastly, sit back and enjoy the fruits of your labor, as these nutritious salad greens will make a wonderful addition to the garden and your plate.

For more information on vegetable gardening, connect with your local Illinois Extension county office at go.illinois.edu/ExtensionOffice.

Prepare your trees for severe weather

By Horticulture Educator Emily Swihart

Spring showers, summer thunderstorms, a winter dusting of snow; these are familiar weather events for Midwesterners, but as climate changes so do weather events. Extreme weather is increasing in Illinois.

Over the past 120 years, significant changes have occurred that are causing more extreme weather events, according to a recently published report from The Nature Conservancy in Illinois “An Assessment of the Impacts of Climate Change in Illinois.” Heat waves have increased, and as a result, summer storm intensity has increased. The number of extremely cold days, with temperatures less than 32°F, will decrease and the freeze-free season will be extended. Warmer winter temperatures result in heavy rain and snow events.

Photo by Sarah Hughson. Storms in any season can damage trees. Preventing damage starts before a tree is planted by selecting the right species for the site.

The impact of climate change is not limited to humans. Plants, especially long-lived plants such as trees, are affected by these changes too.

So many of us love the trees in our lives and it can be devastating to see one fail because of a weather event. Taking actions before and after a storm can help promote tree resilience and longevity.

Regardless of the type of storm, healthy trees are better able to withstand severe weather. Healthy trees are well balanced in form, free from disease and injury, and have adequate root systems.

Proper, regular care of young trees contributes to the development of healthy mature trees. Planting the right tree in the right place is the first step to having resilient trees.

Tree species vary in site condition preferences and tolerances so matching tree requirements to site conditions will promote its establishment and overall health. Assessing a tree’s form and making proper pruning cuts when necessary, can create a canopy that is well balanced, encourages a single leader, and has strong branch attachment angles. Providing supplemental water to young trees during times of drought encourages root system development. Strong root systems support healthy canopies by providing adequate amounts of water and nutrients and help anchor the tree.

During a severe weather event, extra stress is put on the tree. Snow and ice storms add extra weight to the branches and cause breaking or failure. High winds can ‘push’ trees over in an event known as wind throw when root systems are not capable of resisting the extra force put on the canopy. Winds may also cause tree trunks to fail at weak points or trunks may sustain damage due to twisting of the canopy.

Drought stress can cause short- and long-term damage to trees. Extreme heat can contribute to canopy dieback and health decline. Extreme cold can cause twig and branch die back or destroy flower and leaf buds.

After a storm or weather-related event, your safety is the priority. Stay away from any fallen powerline or tree interacting with a powerline.

Utility lines should always be considered live and dangerous. Call the utility provider before damage assessment and site clean-up.

After a weather-related event, many factors contribute to determining which trees require maintenance to restore health or have sustained fatal injuries. A certified arborist is a trained professional who can assist with assessment and tree removal if necessary. It is recommended that routine inspections be conducted on trees remaining on a site to monitor for decline or disease.

Finally, trees provide a wide variety of services in our communities – from cooling homes to creating habitat for wildlife. If trees are lost, after clean-up has occurred, replanting is the final step in recovery. Planting and caring for trees ensures that the landscape will continue to have these life supporting species for years to come.

For more information on tree selection or care, connect with your local Illinois Extension county office at go.illinois.edu/ExtensionOffice.

Give summer-blooming bulbs a second chance, store them overwinter

By Horticulture Educator Ken Johnson

Plants such as cannas, caladiums, dahlias, elephant ears, gladiolus, and tuberous begonia can make a great addition to the landscape. These plants are commonly referred to as tender bulbs, or summer-blooming bulbs. Not all of them actually grow from bulbs, but this is what their fleshy storage structures are commonly referred to as. Other storage structures include corms, rhizomes, tubers, and roots.

Unlike spring-blooming bulbs such as tulips and daffodils, these tropical plants will be killed by our cold winter temperatures if left outdoors. So, if you don't want to have to buy new bulbs every year you’ll need to dig and store them indoors for the winter.

Keep an eye on the plant’s foliage. Once the leaves begin to yellow or have been killed by a frost, the foliage can be cut back. The plants should be dug up within a few days of a frost to make sure rot-causing organisms don't enter the bulbs. Be careful when digging plants; if the bulbs are accidentally cut or “skinned” this creates an entry for pathogens that can quickly spread disease.

One way to avoid damaging the bulbs is to begin digging several inches away from the plant. Loosen the soil all around the plant, then lift the entire clump. After the clump has been lifted, remove any excess soil on the bulbs and discard any damaged bulbs. Using a digging fork can also help avoid causing damage to bulbs.

Most bulbs will need a curing, or drying, period before being stored for the winter. This can be as short as one to three days or as long as three weeks for plants like gladiolus and callas. While drying, keep the bulbs out of direct sunlight and in a well-ventilated area with temperatures around 60°F to 70°F.

Before storing bulbs inspect them again for any signs of disease or insects. Discard or treat any bulbs that may have pest problems. If you store them with 'healthy' bulbs the problems can spread over the winter and become a much larger problem.

It's also a good idea to label what the bulbs are so that you know what's what come spring. There's not much more frustrating than having a bunch of bulbs and having no idea what's what.

Dried bulbs can be stored in 2 to 3-inch layers of peat moss, sand, vermiculite, sawdust, or coconut coir in a well-ventilated container such as milk or bread crates or cardboard boxes. Try not to let bulbs touch one another while they are being stored. This will help prevent the spread of rot between bulbs.

Store bulbs in a cool area with temperatures around 40°F to 50°F such as an unheated garage or unfinished basement.

Periodically check your bulbs throughout the winter and remove any that appear to be rotting. Also, check the moisture levels. If bulbs are beginning to shrink and become wrinkled, moisten the media they are being stored in with a spray bottle. Just make sure not to moisten them too much because that can lead to rot.

For more information on plant care, connect with your local Illinois Extension county office at go.illinois.edu/ExtensionOffice

Find gourds absorbing? Try growing a loofah sponge

By Horticulture Educator Christina Lueking

Gardens can grow a variety of surprising things, but one item you wouldn’t expect to find grown next to beans and tomatoes is a loofah sponge. But one member of the Cucurbitaceae family does just that.

Photo by Christina Lueking. While most people think a loofah sponge comes from the ocean, Luffa aegyptiaca, is actually a member of the Cucurbitaceae family like squash or cucumber.

While most people think a loofah sponge comes from the ocean or at least an aquatic plant, it’s actually found on a trellis in a garden. A loofah, or luffa, plant is considered a vegetable. Luffa aegyptiaca, is a member of the Cucurbitaceae family like squash or cucumber says Christina Lueking, University of Illinois Extension horticulture educator. This gourd is starting to show up farmers markets this time of year and you may be curious to try growing it next year.

The first time seeing one growing you might think it is a very long cucumber. The vines grow extremely long and produce edible fruit growing off them which turn into fibrous gourds when left to mature on the vine.

This outer layer is then peeled away to expose the inner fibers that everyone recognizes as a luffa sponge.

The loofah gourds are a unique addition to any garden, but especially demonstration gardens for youth.

Starting from seed

Loofa seeds should be soaked and started indoors four to six weeks before the last frost. One thing to consider is that you will have to have some patience for this plant as it has a 150 to 200-day growing season. It is important to harden off your transplant to reduce transplant shock before planting in the garden.

Growing needs

Loofa plants need full sun and a strong structure to allow the up to 30-foot-long vines to climb and trellis on while producing fruits in three months. Loofah plants need to be trellised for the weight of the green fruit but as they mature, fruit will dry and lose moisture.

Loofah plants have male and female flowers like winter squash. If pollinators are limited in your garden, hand pollination techniques can be used to pollinate the female flower to increase production. It is recommended that pinching of all flowers and small luffa occur two months before the last frost to direct all the remaining energy to the gourds that will be left to harvest.

Harvest

These diverse plants can be harvested for eating when they are 4 inches to 7 inches long and are traditionally served in Asian dishes. Depending on your growing zone, you will either harvest brown and lightweight gourds or green gourds. Harvest the gourds with hand pruners from the vines.

Those in Southern Illinois’ growing zone 6 climate will need to harvest some green fruit that may not be completely dry and brown before our first frost.

Processing loofah

To process harvested loofah, lay the gourd on a hard surface and press down to crack the skin of the gourd.
Press your thumbs into the skin and pull the skin apart. This process takes more effort if the skin is still green.
Pull the skin or pieces off the fibers to expose a long sponge that contains black seeds.
Rinse the sponge under water and let the sponge sit overnight on a piece of cardboard to dry out.
Some seeds might drop during this process, just sit them out to dry. Once dry, you can shake out the remaining seeds over the cardboard and enjoy your new sponge.

For more information on plant care, connect with your local Illinois Extension county office at go.illinois.edu/ExtensionOffice.

To get in touch with nature, create a sensory garden

By Horticulture Educator Mary Fischer

For centuries, gardens have provided a unique bridge between humans and the natural world. Gardens were viewed by many cultures as a “reflection of heaven on earth.” Today, most gardens are considered landscape projects. But sensory gardens, with their engaging sights, sounds, smells, scents, and tastes once again connect us with nature.

Throughout history, special gardens have been created to enhance the experience by engaging the senses resulting in a profound positive effect on human well-being and behavior. Sensory gardens are designed to entice a visitor to view at close range, to reach out and touch, to inhale a fragrance, to listen and actively experience the garden with all their senses.

These gardens can be designed for spaces of all sizes, from small courtyards or borders, even containers. Garden “rooms” can be designed specifically to stimulate one sense at a time or multiple senses simultaneously.

Sensory gardens are also multi-functional. They can be used for teaching, relaxing, and multiple therapies. Some sensory gardens are design-specific, such as for children, the visually impaired, tactile or kinesthetic learners, and for therapeutic horticulture. Including raised beds and wider pathways allow sensory gardens to be accessible to all.

Sensory gardens often contain additional, non-plant, sensory opportunities. Since people-plant interaction is encouraged, interpretive signs are important. The different textures of hardscapes, like large rocks, are added to provide visual and tactile experiences. Pathways made of various surfaces like sand, woodchips, flagstone, or flat steppingstones craft distinctive tactile and auditory experiences.

Water features create additional sensory experiences through sight, sound, and touch.

Bird feeders invite feathered visitors to also enjoy the garden. These birds offer brilliant bursts of color to please the eye and bird songs to entice the visitor to identify the avian guest.

When choosing plants, remember they need to be people-friendly. Do not use poisonous or allergenic plants. Avoid plants that require pesticides. Select plants with contrasting forms and textures to create visual interest. Low mounds of satiny wormwood next to tall spires of flowers work well in terms of shape and texture. Brushing against plants spilling over the edge of a raised bed offers a tactile experience that can be enhanced by a fragrant plant choice like lavender.

Sight: Adding visual interest to a sensory garden can be as simple as adding plants with different color blossoms and habits like creeping, climbing, trailing, busy or upright. Incorporating plants that bloom at different times of the day or season, differing leaf patterns, unusual bark, and stem colors provides visual interest.

Smell: The sense of smell, adds nostalgic stamps to our memory banks. Scents often trigger remembrances of special places or people. Sensory gardens can be full of intertwining aromas evoking emotions. Sweet smelling fragrances of honeysuckle, gardenias, or peonies and more savory scents of herbs like thyme, rosemary, or oregano provide ample occasions for stimulating long ago memories and creating new memories.

Sound: To stimulate the sense of sound, select flora that make noise when the wind blows through them, such as rattlesnake master, false indigo, bamboos, or ornamental grasses. Wind chimes can increase the variety of sounds. Bird feeders and birdbaths draw the attention of feathered friends to enjoy a feast, take a drink and offer their songs as payment. Dry leaves on the ground or graveled walks add crunch when trod underfoot. Water features further add an extra element of auditory stimuli.

Touch: Gardens designed with a tactile experience are wonderful for children and the visually impaired. The sense of touch allows visitors to enjoy the sensory garden in a more personal, tactile way. Select sturdy plants that will withstand frequent handling as well as those with contrasting textures including soft and fuzzy or rough and spiky. The velvety feel of rose petals, the soft, silky texture of wormwood, the fuzzy foliage of Lamb’s ear, the smooth, leathery surface of a Southern Magnolia, the spiky rosette of sea holly, all increase a sense of connectedness with nature. Succulents have leaves with a range of tactile experiences.

Taste: Visitors can entice their taste buds with edible fruits, vegetables, and herbs. Fruit could include strawberries, thornless blackberries, small fruit trees like blueberries, apples, and peaches to name a few.

Find a detailed guide to creating a sensory garden at go.illinois.edu/SensoryGarden. For more information on plant selection or care, connect with your local Illinois Extension county office at go.illinois.edu/ExtensionOffice.