A Few Favorite Plants

It looks like winter is settling in as the forecast seems to be turning colder in the coming days. It is a perfect time to reflect on the past year in the garden. 

It has been a tough year to grow just about everything, due to the monsoon rains in spring followed by the desert dry months of summer and fall.  In spite of the high and lows, wet and dry, there are a handful of plants that stood out in the landscape – plants that flourished rather than floundered. 

Amsonia hubrichtii ‘Butterscotch’

A favorite plant of mine has been Amsonia.  I like just about all of them including, ‘Sting Theory’, ‘Storm Cloud’, ‘Blue Ice’,  Amsonia illustris and Amsonia hubrichtii.  However, I have really enjoyed the cultivar, Amsonia hubrichtii ‘Butterscotch’.  It has narrow leaves that don’t turn brown on the ends.  The pale blue flower clusters in the spring are a perfect topper to these sturdy plants.  The real show is in fall when the entire plants turns a golden orangish-brown.  The plants will get fuller over time with more and more wands of clean attractive foliage. 

Amsonia hubrishtii ‘Butterscotch’ with Aster oblongifolius ‘Raydon’s Favorite

Aster oblongifolius ‘Raydon’s Favorite’

We have carried Aster oblongifolius ‘Raydon’s Favorite’ for many years at our plant sales.  It continues to be a “favorite” of many customers and I can see why.  In the late fall, the entire plant is covered with dark lavender blooms that pollinators love.  It extends the bloom time in the garden into late October.  The plants are tidy and don’t become leggy like some of the New England asters with their dry leaves on the bottom of the stems.  It does slowly spread but can be divided, shared with your neighbor or planted somewhere else in the garden.  Drought tolerant and tough, it is a plant I have come to admire. 

Scutellaria resinosa ‘Smoky Hills’

One of Katie’s top performers in her home garden has been Scutellaria resinosa. Resinous skullcap is a compact little beauty of the short grass prairie.  The bright blue/purple flowers in summer stand out in the front of a dry sunny border.  It is drought tolerant, durable, and unique.  The neat little mounds with mouse ear grey-green leaves are charming.  It needs well-drained soil.  Plant them with Perky Sue, evening primrose or prairie zinnia.

Scutellaria resinosa Photo courtesy of Craig Freeman

Schizachyrium scoparium ‘Twilight Zone’

I have really come to appreciate grasses in the garden.  The movement and texture in the garden is nice especially through the winter. There is so much diversity and heights of grasses to mix and match in your landscape.  A beautiful little bluestem that has performed well for us has been Schizachyrium scoparium ‘Twilight Zone’.  This is not your typical little bluestem.  It displays beautiful steely-blue foliage with flower spikes of varying purple shades. It seems to be constantly changing through the seasons, slowly shifting to bright purple during autumn.  It is a taller grass that will grow 4 to 5 feet in height and reach a spread of about 2 to 3 feet.  The beautiful foliage will transition to reddish-orange in the fall.  As you know, little bluestems are favorite overwintering homes for insects and pollinators.  The seeds are winter foods for a many types of birds.

Little Bluestem Twilight Zone Photo courtesy Walters Gardens.

Diervilla lonicera x ‘Kodiak Orange’

This spring I needed some shrubs to go around the deck in my backyard.  I planted a Viburnum ‘Blue Muffin’ along with a cross-pollinators Viburnum ‘Little Joe’ to make sure they produced fruit.  There was a silky dogwood called ‘Red Rover’ along with a native bush honeysuckle Diervilla lonicera ‘Kodiak Orange’.  I have been impressed with the honeysuckle.  It never wilted compared to the viburnum and dogwood.  It developed tiny yellow honeysuckle-like flowers throughout the summer that attracted butterflies and other pollinators.  The orange-green leaves have turned yellow-orange this fall which is a bonus.  It is quite adaptable to dry soil once established.  My yard is quite shady except mid-afternoon and they thrived.  There are many non-native and invasive honeysuckles including Morrow’s honeysuckle, Tatarian honeysuckle, Amur honeysuckle, and Japanese honeysuckle (Lonicera spp.).  Although somewhat similar in appearance Diervilla are native and not invasive.  One thing I have learned about invasive honeysuckles is that they have hollow stems.  Native honeysuckles have solid stems. 

Fall color of Kodiak Orange

I hope you have been able to think back through this year and reminisce about your garden successes.  We often put so much time and effort into our gardens that we don’t step back and take in the scenery.  Also, remember that a beautiful landscape that we enjoy has ties to ecology, creating habitat and helping wildlife too.

Grateful for the Beauty of Nature

I am grateful for the beauty of nature which reminds me to slow down and take a deep breath.

Tallgrass Prairie National Preserve. Photo by Brad Guhr.

How was it possible, I asked myself, to walk for an hour through the woods and see nothing worthy of note? I who cannot see find hundreds of things to interest me through mere touch. I feel the delicate symmetry of a leaf. I pass my hands lovingly about the smooth skin of a silver birch, or the rough, shaggy bark of a pine. In spring I touch the branches of trees hopefully in search of a bud, the first sign of awakening Nature after her winter’s sleep. I feel the delightful, velvety texture of a flower, and discover its remarkable convolutions; and something of the miracle of Nature is revealed to me. Occasionally, if I am very fortunate, I place my hand gently on a small tree and feel the happy quiver of a bird in full song. I am delighted to have the cool waters of a brook rush through my open fingers. To me a lush carpet of pine needles or spongy grass is more welcome than the most luxurious Persian rug. To me the pageant of seasons is a thrilling and unending drama, the action of which streams through my fingertips.
At times my heart cries out with longing to see all these things. If I can get so much pleasure from mere touch, how much more beauty must be revealed by sight. Yet, those who have eyes apparently see little. The panorama of color and action which fills the world is taken for granted. It is human, perhaps, to appreciate little that which we have and to long for that which we have not, but it is a great pity that in the world of light the gift of sight is used only as a mere convenience rather than as a means of adding fullness to life.

Helen Keller, Three Days to See

In every walk with nature one receives far more than he seeks.

John Muir
Pale purple coneflower. Photo by Brad Guhr.

He will see the beauty, as well as the unity, of the whole, and know the two cannot be separated. We love (and make intelligent use of) what we have learned to understand.

Aldo Leopold

Follow down the leg past knee
on down where
world and body meet.

The sole you’ll find
amid the grime.
calloused pads that bruise and bleed.

Like Achilles
our strength will be
the same that makes us weak.

So descend your frame
and find your soul
hid on the bottom of your feet.

John Simmering

HAPPY THANKSGIVING!

Butterfly milkweed at CSFL. Photo by Brad Guhr.

Valley Center Public Library Pollinator Garden

Earlier this year, I created a native plant design for the Valley Center Public Library. After a group of volunteers helped get it planted, they have diligently weeded and watered it through the summer. Thankfully, they have an automatic sprinkler system. But they established the plants by hand watering, which was no small task.

Sumac next to small foot bridge over the drainage swale

Focal Points

Last week I took a field trip to check out the progress of their garden. It survived the summer and really filled in nicely. Some of the highlights were the Raydon’s Favorite aster, Twilight Zone little bluestem, American beautyberry, and switchgrass. The solar powered bubbling fountain and large butterfly bench donated by a local resident add a nice spot to sit and enjoy the garden.

Butterfly bench in the garden

Opportunities for Education

The garden is just north of the new library. It has walking paths and a small bridge over a wet area. It has a diverse selection of plants to create habitat for pollinators. We included several types of milkweed scattered throughout the garden, which will attract monarch butterflies. The adult monarchs laid eggs on the milkweed, which hatched into caterpillars, which then turned into adults. The garden stewards were able to share this lifecycle with the children and adults who visited the library.

Bubbling fountain perfect for supplying water to pollinators

It was a warm sunny day when I visited. There were dozens of pollinators working on the asters, which were in full bloom. The garden has been a tremendous success. The ladies who manage the site have done a wonderful job. They are connecting people of all ages, but particularly children, to the outside world and showing them different pollinators that can be attracted to a garden using native plants.

As the garden matures, the educational opportunities will become more numerous. These connections with nature are important formative experiences that will impact people for years to come. Keep up the good work!

It’s hard to see but this Aster ‘Raydon’s Favorite’ was covered with all sorts of pollinators.

Final update: Buffalograss Experiment

As the growing season comes to a close, I like to take account of the garden before it goes completely dormant. Certainly, this has been a challenging year in the garden. The plants I installed last May in front of my house are still alive, but it took daily watering through the summer to keep them going. It is safe to say that without regular attention and water, I would have lost all of those tiny plants. I am still watering them twice a week.

Aster oblongifolius ‘Raydon’s Favorite’
Amsonia hubrichtii ‘Butterscotch’

Here at the Arboretum, I find the resiliency of the prairie and certain display beds encouraging. While they are under stress, these plants adapt well to the high and lows along with wet and dry conditions. I have also been monitoring the buffalograss experiment I started over two years ago in the fall of 2020.

Our Experiment

As a reminder, in the fall of 2020, we tried a new seeding technique with buffalograss. We had our area prepared and ready for planting. That November, we seeded the area with annual ryegrass and buffalograss seed. The ryegrass is a cool season grass that prefers cooler weather. Once it germinated, it held the soil through the winter while the buffalograss seed naturally planted itself with the freezing and thawing of the soil. The round buffalograss seeds did not germinate because soil temperatures were below 60 degrees.

Area before planting, November 2020
Annual ryegrass mowed for the second time in the spring of 2021

The Next Year

In the spring of 2021, the buffalograss seed germinated as the soil temperatures warmed. By May, the new seedlings had started to spread under the canopy of the ryegrass growing from the previous fall. As the temperatures warmed into the summer, the annual ryegrass faded since it is a cool season grass and the buffalograss became more prominent. By the end of the summer, new small clumps of buffalograss established, slowly spreading but healthy.

Since Germination

We mowed the annual ryegrass weekly that first year. It is important to keep the canopy open so the sun could warm the soil allowing the buffalograss seeds to continue to germinate. Buffalograss takes two to three weeks to germinate. The seeded annual ryegrass expired on its own with warmer summer temperatures. As the ryegrass died, the roots of the ryegrass continue to hold the soil as the buffalograss spread slowly the rest of the summer.

Buffalograss clump will benefit from a pre-emergent herbicide application next spring.

UPDATE: Analysis and what I would do differently

I would deem this buffalograss experiment a success. Honestly, I thought the buffalograss would spread more over the past year, but there are many clumps sprinkled throughout the area that are getting larger. The additional costs to purchase annual ryegrass seed are offset by the time and water saved compared to the traditional seeding method.

We will be putting down a pre-emergent next spring to keep the crabgrass and other summer annuals from germinating. Some pre-emergent herbicides safe for use in buffalograss are Barricade (prodiamine), Pendulum Aquacap (pendimethalin), Dimension (dithiopyr), and Specticle (indaziflam). There are some nice clumps of buffalograss, but they are hampered by intense weed competition. Weed competition was aided by tillage (soil disturbance), and the backfill soil added along the new sidewalk, which was full of weed seeds.

I would only use this seeding method on smaller areas of less than 1000 sq/ft. In my opinion, larger areas that are properly prepared should be planted from seed in the summer before August 15th. We seeded a larger area this past summer to buffalograss using the traditional method and had good germination and coverage. Here are some other things I would do differently:

  • Reduce the seeding rate of the annual ryegrass: Though the packaging recommends that you plant 3-4 lbs./1000 sq. ft. I would only seed 2-3 lbs./1000 sq. ft. The seeds will still germinate to hold the soil through the winter, but not be so dense that they shade out the buffalograss seeds in the spring.
  • Plant buffalograss seed first and slightly cover it: I had some buffalograss seed float off the soil as I established the annual ryegrass seed last fall.
  • Start the process earlier in the fall after the first freeze (October 15): It is better to establish annual ryegrass with slightly warmer temperatures, but not so warm that the buffalograss seed germinates.

Words of Encouragement in a Drought

We have all seen wonderful pictures of lush plants and fertile prairies in magazines, on television, on social media or other websites. These plants seem to be growing effortlessly. They have beautiful blooms with scarcely a leaf out of place. That is not the reality we are living in Kansas right now. Honestly, our gardens look a little tattered and worn down from the summer they have endured. The drought has taken its toll. 

The sun sets on another growing season.

Frankly, this time of year we might feel as tired as our garden looks.  We might even question why we do it. But don’t forget that a sustainable and resilient landscape doesn’t just happen on its own. It takes a little effort, but the rewards are worth it. Consider all the benefits of a native garden:

  • Saves water.
  • Doesn’t require fertilizer or pesticides.
  • Adapts to our climate.
  • Provides erosion control.
  • Reduces stormwater runoff.
  • Restores natural habitats.
  • Preserves biodiversity.
  • Attracts pollinators.

Fortunately, the native plants have survived. There are still some blooms on goldenrods, heath asters, blue sage, New England aster and aromatic asters in spite of the ongoing drought. The grasses, though stunted, are seeding out and have attractive autumn colors. True, it can be discouraging this time of year as you compare your garden to those idyllic gardens on paper or the web, but don’t lose heart. Your habitat garden is still functioning as it should.

Pink Muhly Grass in full bloom

Fall is the time to step back and appreciate your habitat landscape for what it is. Certainly, there might be more you could add or do, but this is enough for now. A successful native garden is more than aesthetics. You understand that all of these ecological benefits are important in creating a successful garden too. When you see that your garden is inviting to a diverse group of pollinators and wildlife, you know that you are creating something worthwhile.  

Resilient autumn landscape (Aromatic aster, little bluestem, new england aster, Missouri blackeyed susan seedheads, and false sunflower)

Plant Profile: Goldenrods (Solidago sp.)

Right now in prairies, woodlands, roadside ditches and home gardens, wonderful displays of native grasses along with wildflowers blooming yellow, white, and lavender are putting on quite a show. The yellow wildflowers are most likely either sunflowers or goldenrods. Each is quite beautiful and teeming with pollinators.

Solidago ‘Wichita Mountains’ blooming in the Compassionate Friends Garden

Goldenrods are just as diverse and variable as sunflowers. While many landscape plants have already reached their peak and the flowers have faded by September, goldenrods have become the stars of the show as they brighten up the landscape. Their golden yellow autumn inflorescences are striking.

In spite of their attractiveness, goldenrods have a reputation for causing allergies. In truth, this is unlikely, because goldenrod pollen is large and heavy and is not carried by the wind. Rather, it is giant ragweed (Ambrosia sp.) that is spreading pollen through the air at the same time.

These wildflowers are insect-pollinated by many wasps, moths, beetles, honey bees, monarch butterflies and other beneficial pollinators searching for a sip of nectar. In total, 11 specialist bees and 115 different caterpillars need these plants. There are around 50 species of insects with immature forms that feed on the stems of goldenrod. In addition, seeds and foliage provide food for some birds and mammals. Across the board, goldenrods are of huge value to wildlife and one of the keystone wildflowers for pollinators.

Gray Goldenrod-Solidago nemoralis

Goldenrods are adaptable to a wide range of conditions in nature, making them a great choice as a landscape plant. They grow naturally in soils from wet to dry. Even the drought conditions we have been experiencing have not kept these denizens of the prairie from blooming. There is a goldenrod that will grow in your garden.

For all their positive attributes, there are goldenrod species that don’t belong in a formal garden. Canada goldenrod for example is a highly aggressive species that spreads by underground rhizomes and seed, ultimately pushing out other smaller desirable plants. It will take over a garden in a couple of years. However, in a prairie setting with the deep roots of native grasses and competition from other plants, it can be mostly kept in check. That is why we recommend clump-forming goldenrods as a more reliable choice for the landscape relegating those aggressive species to the prairie or outskirts of the landscape (along a fence or in an alley) where they are free to roam and spread.

I like Solidago rigida, Solidago nemoralis, Solidago ‘Wichita Mountains’, Solidago canadensis ‘Golden Baby’, and Solidago ‘Fireworks’ for sunny areas. For shade, I choose to plant Solidago odora, Solidago ulmifolius or Solidago caesia. It is safe to say that goldenrods are powerhouse plants that deserve a place in your native garden.

Rigid Goldenrod-Solidago rigida (top) and gray goldenrod (bottom)
Solidago rugosa ‘Fireworks’

Fall Planting of Native Grasses

One of the questions we get at every fall plant sale is “can we plant these grasses now?” The answer is “yes, we encourage fall planting of native grasses”, but with some caveats.

Here are a few questions to answer before you jump into planting native grasses this fall such as:

  • Is your area ready to plant now?
  • Are you able to water it daily for the first few weeks and into the winter if needed?
  • Do you have the right location for these grasses?

I tend to err on the side of caution for late fall planting because losses can be incurred. However, you can be successful if you follow a few guidelines.

Around South Central Kansas, our first average frost is October 15. Typically, we plant native grasses as soon as possible in late August or early September to give them more time in the ground to get established. As a general rule, it is best to have native grasses in the ground three to four weeks prior to the first fall frost. This will give the plant time to get established with roots fully attached to the soil to absorb water and nutrients through winter.

Prairie Dropseed planted last fall

This attachment by the roots to the soil is so important because it keeps the grass from being heaved out of the ground. The natural freezing and thawing of the soil during the winter can be extremely strong, pushing partially established plants out of the ground and breaking roots, which results in desiccation and death of the plant. Properly establishing plants before winter will protect them from this force.

Another factor to successfully transplanting grasses in the fall is soil temperature. Typically, native grasses will continue to grow (root) with soil temperature above 60 degrees. So installing grass plugs in August through mid-September is a proven strategy, because soil temperatures remain optimum until after the first frost.

Switchgrass after one year of growth

We have had success with planting native grass in the fall. The most obvious benefit of this approach is that the grasses will break dormancy next spring fully established and ready to grow. As temperatures warm they will have a head start over early spring plantings.

Note: It is always good practice to check the soil around fall planted perennials (including grasses), trees and shrubs during the winter for moisture. If the top one to two inches of soil is dry, it is good to give them a light watering. Remember, they are dormant so they don’t need much.

Warm Season Grasses for fall planting:

  • Big Bluestem Andropogon gerardii and cultivars
  • Sideoats Grama Bouteloua curtipendula
  • Blue Grama Bouteloua gracilis
  • River oats Chasmanthium latifolium
  • Pink Muhly Grass Muhlenbergia reverchonii
  • Mexican Feather Grass Nassella tenuissima
  • Switchgrass Panicum virgatum and cultivars
  • Little Bluestem Schizachyrium scoparium and cultivars
  • Indiangrass Sorghastrum nutans
  • Prairie dropseed Sporobolus heterolepis

Cool Season Sedges and Grasses for fall planting:

  • Appalachian Sedge Carex appalachica
  • Bicknell’s Sedge Carex bicknelli
  • Pennsylvania Sedge Carex pensylvanica
  • Rosy Sedge Carex rosea
  • Texas Sedge Carex texensis
  • Bottlebrush grass Elymus hystrix
Mexican Feather grass planted in the fall of 2020

Plant Profile: Kentucky Coffeetree (Gymnocladus dioicus)

When one thinks of the Great Plains, trees are often the last thing to cross one’s mind. Surprisingly this region is home to a number of species that have found their way into yards and parks throughout the United States. The honey locust, American elm, black walnut and silver maple are as common in front yards as they are along streams and patches of woodlands of the plains. One of the more beautiful native trees found in this region is the Kentucky coffeetree, a member of the legume family. Kentucky coffeetree can be found along the eastern portion of Kansas. The tree derives it name from a common practice among early Kentucky homesteaders of grinding the seeds to make a coffee-like drink.

Mature Kentucky Coffeetree (Wikipedia)

Though somewhat uncommon in landscape plantings, the coffeetree offers many ornamental attributes. A large tree, it can reach 60 feet in height with a 30 foot spread. As of March 2022, the Kansas Forest Service state champion Kentucky coffeetree, located at Fort Leavenworth, currently stands at 100 feet tall. As the tree matures, the bark forms scaly ridges with curled edges. In winter the ascending branches present a picturesque silhouette against the winter sky. Written descriptions have labeled the tree “clumsy” looking after the leaves drop. While young trees can appear awkward their first few years, mature specimens develop stout trunks and main branches, reminding one of their innate toughness and durability.

In spring the tree may be slow to leaf out, but the patient observer is soon rewarded with bipinnately compound, bright green leaves with dainty, ovate leaflets that give the tree a soft, fine textured appearance throughout the growing season.

The bipinnately compound leaflets

Kentucky coffeetrees are individual male and female trees. The botanical term for plants with male and female flowers on separate individuals is dioecious, a condition also found in Ginkgo, juniper, and Osage orange. Flowers appear in May and June as graceful racemes. The male flowers are somewhat inconspicuous and green-yellow, while the female flowers are somewhat larger and pale yellow-white. Both types of flowers are quite fragrant. Each of these flowers are favorites of pollinating insects.

Creamy white flowers in the spring (Wikipedia)

Fall color is often a subdued yellow and female plants will often produce a reddish brown pod filled with incredibly hard, round, slightly flattened seeds. The hard coats allow seeds to lay dormant in the ground for long periods of time until weathering and soil bacteria wear down the tough shell, allowing germination to occur if temperature and moisture are adequate. Professional growers often soak the seed in concentrated sulfuric acid to thin the coat enough for water and gas exchange (a dangerous practice for the average home gardener). Another option is to use fine sand paper to sand down the shells so several seeds will potentially sprout. Don’t sand too much.

Bean-like pods and seeds of Kentucky coffeetree

Due to the coffeetree’s large size and the sometimes “messy” pods from the female trees, it is often not the best selection for the average yard. However, it is well-suited to large open areas, along streams and in park settings. It is not particular about soil, but best growth occurs in deep moist ground. Drought tolerant, it experiences very few problems.

In the wild, small colonies of coffeetree can be found when new trees form from the root suckers. This is usually not a problem in the landscape if the tree is mulched and regular mowing occurs around the tree. Transplanting in most successful with small plants, because the tree develops a course fibrous root system that limits the transplanting success of larger trees.

In the Arboretum’s bird watch area, a small coffeetree is planted just below the big bridge.

I like good coffee. Lucky for us that our coffee supplies for drinking are more than adequate, but one should still consider this beautiful, tough native tree for your landscape.

Roots of Native Plants

The prairie is a unique ecosystem with great diversity of plants. This diversity is extremely important because there are so many niches within the prairie. These are created by differing rainfall averages across the expanse of the landscape from west to east, different soil types and different depths of soil for plants to grow. This adaptability and resiliency of plants is correlated in part to the root systems associated with many native plants.

Xeric Garden
Interpretive signage located on the Dyck Arboretum grounds. Artwork by Lorna Harder.

Plants grow in community

For so long, we have thought that the deep roots of many of these native plants translated to their ability to withstand drought and extreme temperatures. However, more research is pointing to the fact that most of the water absorption occurs in the top two to four feet of the soil profile. As it turns out, plants grow in community with each other and each above ground layer (groundcover, seasonal theme, and structure) draws moisture from different zones within those few feet of soil. This allows them to grow harmoniously together and not in competition with each other. This is the matrix planting concept, which mimics what happens naturally within a prairie. 

Narrowleaf Coneflower in the Flint Hills

Why are deep root systems important?

What we see above ground is typically only a third of the overall plant.  Roots exist out of sight and can reach anywhere from 8 to 14 feet into the soil.  Yes, these extensive roots do absorb moisture and nutrients but they do so much more.  They play an important role in helping a plant grow, thrive and improve the environment around them.

These hidden roots also:

  • Anchor the plant in the soil as plants try to reach for sunlight
  • Store excess food for future needs underground
  • Nourish the soil by dying and regrowing new roots each year, which builds top soil 
  • Fix nitrogen in the soil (legumes)
  • Increase bio productivity, by absorbing and holding toxins and heavy metals, carbon sequestration
  • Prevent erosion – fibrous roots hold the soil and absorb more runoff (as in a rain garden)
Butterfly Milkweed

I believe that native plant roots make these prairie plants resilient in the landscape. They are adapted to our local soils, rainfall and nutrients. In the 2011 and 2012 drought years, we observed native plants blooming in the fall, even after enduring 50+ days of 100 degree temperatures. This could not have happened without a healthy, sustaining root system. 

So while we learn more about the root systems of native plants and the vital role they play within the life of a prairie, we know that bringing native plants back into our environments continues to have so many positive benefits. Let’s work at getting more native plants into our landscapes and let them flourish.

Saturated Soils and Wilting Plants

This year we have been facing many environmental challenges from wind, drought, torrential rain for a lucky few, and now soaring temperatures. Nobody said gardening in Kansas would be easy. One of the more common problems we see in spring is wilting plants, especially those that are newly transplanted. This is true after the big rains last week and now the heat of this week. The new gardener may wonder – “what’s wrong with my plants?”

Saturated Soils

The heavy rain has resulted in saturated soil. Plants need water, but standing water for hours or even days depletes the soil of valuable oxygen. The roots need oxygen present in the soil, but as voids are filled with water, the oxygen is removed and root systems can become damaged. The fine root hairs die from lack of oxygen. These fine hair roots are vital for water and nutrient uptake by the plant. Whether it is a perennial or vegetable crop like tomatoes, the plants wilt because the uptake of water has been interrupted.

Will the wilting plants recover?

A number of factors affect the plant’s ability to overcome a flooding episode. How long the plants were flooded, drainage away from the root system, type of soil, type of plants (think about their natural habitat: some plants appreciate wet soils while other don’t), and how long the plant has been established. A newly established plant will be more affected than a mature plant.

Liatris wilting

Many vegetables crops are sensitive to flooding or saturated soils, but if the soil dries out quickly they will usually recover on their own with no help from us. Heavily mulched plants with more than two to three inches of mulch tend to stay wet too long for many perennials. If you see this wilting happening, check soil moisture. The mulch is not allowing the soil to dry out and may be damaging the roots. Rake back the mulch for a few days to encourage the soil to dry out.

If the soil stinks, then it has transitioned into an anaerobic state and everything is killed in the soil, including microbes and roots. Not a good situation. At this point it is very difficult to bring a plant back, because it is too badly damaged. Native plants generally appreciate good drainage. Root rot or crown rot are two of the most common problems, because the soil stays wet too long. As an example, narrow-leaf coneflower (Echinacea angustifolia) grows on rocky hillsides with keen drainage and no standing water. Planting one of these coneflowers in a flat garden with heavy clay soils is a recipe for disaster.

This time of year, gardeners should also be on the lookout for increased incidences of diseases such as early blight and powdery mildew. Humidity and excess moisture can quickly damage plants with these diseases, too.

Yellow Leaves

Echinacea turning yellow from too much water

Yellowing foliage can also be a problem after a heavy rain event. This is a visual indicator of compromised roots, but also the leaching out of nitrogen in the soil. Nitrogen is mobile in the soil and moves downward away from roots with moisture. An application of slow-release fertilizer like Osmocote or a liquid fertilizer will green the plant back up over time.

I only recommend fertilizing fully established perennials, i.e. plants you put into the ground last year. Fertilizing newly planted perennials will cause excess top growth without a sustaining root system. With native wildflowers and grasses, it generally takes three to five years to develop a sustaining root system.

To avoid these problems, it is critical to match plants to your site. Good drainage and keeping moisture away from the crowns of the plants will keep your plants healthy too. Don’t put too much mulch around your plants, especially the main stem. Plant your garden densely and let the plants be the mulch.

If you do mulch your garden, only put enough to just cover the soil. Usually one to two inches is enough. Allow the plants to develop roots that tap into the moisture and nutrients. We need the spring rains, but sometimes we can get too much for our newer perennials.