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.

Photo used by permission from Nature Education-1995 Conservation Research Institute, Heidi Natura.

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.

The first year: Getting native plants established

Originally published on May 27, 2020

The prairie communities we see are diverse and complex.  Plants, intricately woven together, crowd out weeds and harmoniously coexist.  When you look at a prairie, you only see about 1/3 of the plant.  The root systems that sustain these native plants make up the remainder, because they reach deep into the soil.  The first year is so critical to the whole process of getting native plants established. Developing these root systems properly is vitally important and the establishment period takes time.  Here are a few steps I take to get my new native plants started. 

Prairie Photo by Brad Guhr

Planting

I like to lay out the entire area by placing the plants where they are supposed to be planted.  This does a couple things: first, it helps with proper spacing of the plants and second, it helps to visualize the final outcome.  Think about mature size, rather than what the plants looks like in its infant state. 

Now that we have the plants laid out, we can start putting them in the soil.  It is critical to not plant them too deep.  In our heavy clay soils, it is best to plant them level or slightly higher (1/8 to ¼ inch) than the soil line, especially in heavier clay soil.  This keeps the crown drier, which is important for disease control.  Over time, these natives will develop at the depth they prefer to grow in. 

Lay out entire bed for proper spacing

Watering

Now that the plants are in the ground, they need frequent watering until they get established. Even drought-tolerant plants need to be watered daily until they begin to root and connect with the soil around them. Keep in mind that improper watering is the most common reason for plant loss during the establishment period. 

For me, I water each new area by hand rather than with a sprinkler. It helps me control the amount of water each plant receives and directs it to the intended plant.  I water every day for the first two weeks depending on the weather.  After that first two weeks, you should start to see new growth. 

For the next few weeks, I water every other day or every third day as needed, monitoring the planting each day for signs of stress/wilting. 

Even after this month long process of establishment, each plant must be monitored and watered through the following summer, fall, winter and spring.  Native plants are not established until the second summer. 

Remember, it takes a few years for those roots to fully develop.  If your plants are properly sited, you will not need to water much after the first full year.  However, if you must water your area during a dry period, natives will appreciate deep and infrequent watering. 

Using a watering wand to direct water on to new plants

Don’t Fertilize

People ask me all the time about fertilizing native plants.  As a general rule, I don’t fertilize our native plants especially during that first year. Think about those small plants in the ground and what will happen to them if they are fertilized. They will have tremendous top growth that is not sustainable by the small root system. This will put the plant under stress and slow its progress. 

Natives are resilient and adaptive. The deep roots most often will find the nutrients and moisture each plant needs.

Mulch

In the book Planting in a Post-Wild World: Designing Plant Communities for Resilient Landscapes, Thomas Rainer and Claudia West develop the ideas of layering plants. There are usually at least three distinct layers of plants: the upper layer filled with taller structural plants used to frame and punctuate the landscape, the middle layer filled with ornamental flowering plants and the ground level that weaves the other layers together and shades the soil, which controls weeds. 

These layers mimic natural plant communities and each layer is important for the health of the plants.  A collection of plants living in community can be extremely drought tolerant and water-thrifty.

If you decide to mulch your display beds initially, only place one to two inches of mulch down and keep it away from the stems.  This is fine as the beds are first established. As they mature, less mulch is needed because, with the right care, the plants become the mulch.  Something to think about is whether you have seen mulch in the prairie?  No, the plants eventually co-mingle and intertwine to push out weeds.     

Creating a native landscape takes time.  With each new plant established comes an expectation of a brighter future. Often, we garden and landscape our yards with the anticipation of what we will get rather than what we are giving back.  By adding native plants to our gardens, we will help make our gardens not only beautiful, but also productive and full of life.

Pine Diseases Changing Landscapes Forever

The Arboretum continues to change. If you visited the Arboretum in the early years, you would have seen many different types of pine trees and other evergreens planted in groves. These pine trees initially flourished, even though they are not native to Kansas. However, over the past 20 years, the Arboretum has lost many of those original pine trees.

This is not an isolated problem. Whole shelterbelts, specimen trees and screens have been decimated by diseases exclusive to pines. What are the most common pine diseases and what can be done to control their spread? That is a question I’m often asked and there are no easy answers. I do suggest Kansas State Extension and online resources for more information.

Pine Wilt

Pine Wilt threatens to remove several pines permanently from the landscape. Discovered in Missouri in 1979, pine wilt is most serious on Scotch Pines but can infect Austrian and White Pines. Since that initial report, it has continued to move westward and has completely decimated all of the Scotch pines in the Arboretum.

Symptoms for Pine Wilt usually appear from August through December and cause the trees to wilt and die rapidly in a month or two. Trees may survive for more than one year but the result is always fatal. The needles turn from bluish-gray to yellow/brown and remain attached to the tree.

Several organisms play a role in the death of a tree. The pinewood nematode is transmitted from pine to pine by a bark beetle, the pine sawyer. Once inside the trunk, the microscopic worms feed on the blue stained fungi that live in the wood but also on the living plant cells surrounding the resin canals and water-conducting passages, essentially choking the tree. There are no highly effective management tactics. Dead pines should be promptly cut and destroyed before warm weather of spring. If this is not done, beetles can continue to emerge from the logs and infect more trees.

Austrian Pine dead from disease that will be removed this spring in the Arboretum

Other Pine Diseases

Foliar diseases such as Sphaeropsis Tip Blight (STB), Dothistroma Neddle Blight (DNB), and Brown Spot of Pines (BSoP) are caused by types of fungi that can infect both the new and old growth. Some of the species affected by these diseases include Austrian, Mugo, Scots, and Ponderosa Pines. The symptoms of STB appear on the current year’s shoots. As the new shoots emerge in the spring, they are susceptible to infection by the fungus. Any damaged area provides the spores a way into the tree. The spores are dispersed by water and require high humidity for germination and penetration of the host tissue. Both DNB and BSoP cause spotting of the needles and eventually premature defoliation. Transmission is again by water and moisture. In a year with many spring rains, the moisture can spread the spores like wildfire and many treatments are needed to keep them in check.

Treatment Options

These three foliar diseases can be treated with multiple applications of copper fungicides and Bordeaux mixtures in the spring and early summer. Treatments are costly and high pressure equipment is needed to project the spray to the top of the trees. It has been my experience that control of these diseases is difficult. Spray timing is critical, densely planted trees are highly susceptible, and infection occurs during excessive rainfall. Thinning trees and removing dead or diseased branches will prolong the life of the tree, but the best defense is to keep the trees healthy by providing adequate moisture and fertility.

Diversity is the Key

One of the key lessons we have learned from this experience is that diversity is vital to a successful landscape. Whether pine trees, deciduous tree, perennials or shrubs, don’t put all your eggs in one basket. Establish a variety of plants adapted to your landscape rather than just one or two species. The truth is that you can do everything right and still lose an evergreen tree. Replant with a diverse variety of species so your whole landscape will not be open to widespread devastation again. There will be other diseases that come, but diversity will give you the edge.

Other Evergreens

New evergreen species are being trialed for adaptability in Kansas, but at this time there are not many viable alternatives other than our eastern red cedar with cultivars such as ‘Taylor’ and ‘Canaertii’. Southwestern White Pine (Pinus strobiformis), Arizona Cypress (Cupresses arizonica), Black Hills Spruce (Picea glauca var. densata) and Pinyon Pine (Pinus edulis) are also viable options. Full descriptions of these trees can be researched on the internet or you can come to the Arboretum and view them in person.

Pines like Ponderosa (Pinus ponderosa), Austrian (Pinus nigra) and Scotch (Pinus sylvestris) have been taken off the recommended tree list because they are so prone to disease. I would highly encourage you to visit the Kansas Forestry Service website at www.kansasforests.org . Once there, choose your region to view a full list of recommended trees for your area along with other informative publications.

Southwestern White Pine
Southwestern White Pine
Arizona Cypress
Arizona Cypress
Arizona Cypress
Arizona Cypress scale-like needles

Defining Common Horticultural Terms, Part 2

We encounter many enthusiastic new gardeners at FloraKansas who have heard about the importance of planting native plants, but don’t yet have the knowledge base needed to establish a successful planting. If you’re dreaming of a flourishing prairie pollinator garden, let me unpack the why behind the what of a few more horticultural terms for you.

Host Plants

Often, the focus for our gardens is on blooms and succession of blooms, more so than host plants.  Beautiful gardens in full bloom are what we see in catalogs, magazine and books. It is natural to gravitate toward these flourishing gardens that nectar-seeking butterflies need to sustain themselves. However, host plants (food for butterfly caterpillars) will keep them coming back to your landscape for years to come.    

It’s important to plan for the entire life cycle of a pollinator. Butterflies need places to lay their eggs.  Think of host plants as the baby nurseries of the garden. Female butterflies will flit and flutter through your garden looking for the right plant to lay their eggs. Some will lay their eggs on stems, or on the underside of leaves, hidden from predators. If you have a variety of host plants, you will attract a variety of butterflies. 

Newly hatched monarch caterpillar on common milkweed (Photo by Brad Guhr)

Ultimately, the goal of any habitat garden is to provide everything those butterfly species need to complete their life cycle. Food for all stages of their life cycle, protection, and water are needed at different times throughout the year. The tiny larvae (caterpillars) will emerge and begin eating on the host plant. As they eat, they grow until they leave the plant and form a chrysalis. It is a fascinating process that you can watch unfold in your own garden. 

Here are a few host plants and the pollinator they attract:

  • Wild Lupine – Karner Blue butterfly
  • Golden alexander – Black Swallowtail butterfly
  • New Jersey Tea – Spring Azure butterfly
  • Columbine – Columbine Duskywing
  • Smooth Blue Aster – Crescent Butterflies
  • Little Bluestem – Leonard’s Skipper
  • Prairie Violet – Fritillary Butterflies
  • Pearly Everlasting – American Lady
  • Milkweeds – Monarchs
  • Paw Paw – Zebra Swallowtail butterfly
Zebra Swallowtail Butterfly on Pawpaw tree at the Arboretum, photo by Janelle Flory Schrock

Resource: Holm, Heather. Pollinators of Native Plants: Attract, Observe, and Identify Pollinators and Beneficial Insects with Native Plants. Pollination Press, 2014.

Sunlight Defined

Knowing how much light you have within your landscape is an important piece to a sound design. By simply watching sun patterns throughout the year, you will be able to determine how much sunlight your garden receives. Industry standards and labeling can then be used to assist in selecting the right plants for your landscape conditions. Here are some terms worth knowing since all plants require sunlight to grow, but differ in the amount and intensity of light needed to prosper. 

  • Full sun – Plants need at least 6 hours of direct sun daily
  • Part sun – Plants thrive with between 3 and 6 hours of direct sun per day
  • Part shade – Plants require between 3 and 6 hours of sun per day, but need protection from intense mid-day sun
  • Full shade – Plants require less than 3 hours of direct sun per day

Full Sun

Not surprisingly, this type of light describes what most prairie plants need. They enjoy open, bright sunny locations with direct sunlight for most of the day. This could also be morning shade/afternoon sun or vice versa, as long as there is at least 6 hours of continuous sunlight. Most of these plants have deeper root systems or adaptations that help them endure this light intensity for the growing season. 

Let experience be your guide when situating plants. Yes, some plants can handle full sun, but need protection for the hot afternoon sun. Or they can handle full sun with consistent moisture. This is the other reason to understand your site, including soil moisture, soil type, root competition and drainage.  All these factors directly affect plants too.  

Sun loving prairie plants

Part Sun and Part Shade

These light definitions are quite a bit different than plants for full sun.  Plants for part sun and part shade obviously require less light, more importantly, the light intensity is a key factor for their endurance and success.  Filtered sun for most of the day or morning sun afternoon shade fit the bill for situating plants.  Too much direct sunlight for too long a period will stunt plants needing part sun or part shade. 

There is often a fine line between getting too much sun that the plants suffer and getting too little light that the plants don’t bloom. For either group, providing direct morning sun is often the best choice.

Full Shade

Most shade plants require anything from the dappled shade found under deciduous trees, indirect light found on the north side of the house or deeper shade found under evergreens. In our area, growing shade plants can be a challenge because we are trying to grow shade plants in what was once a prairie environment with intense full sun. True shade plants often perish because they get too much sun, too much hot dry wind and/or too little moisture.

To successfully grow shade plants in our area, they need protection and consistent moisture. Any shade gardens must mimic the woodland environment. Loamy soils with leaf litter, consistent moisture – but not too much! – and protection from drying winds. It can be a challenge, but shade gardens can be carefully created with the proper light conditions, too.

Dyck Arboretum woodland garden with columbine, woodland phlox, white woodland aster and solomon’s seal

Defining Common Horticultural Terms

There are many horticultural terms that get tossed around in casual conversation. We hear these words or phrases in presentations, and read them in books and seed catalogs. Presenters often assume that everyone knows what they mean without much explanation. Here are a just a few words I use from time to time that I would like to define for you.

Xeriscape

Denver Water coined the term xeriscape in 1981 by combining landscape with the Greek prefix xero-, from (xēros), meaning ‘dry’. Xeriscaping = water-conserving landscapes. This landscaping concept focuses on several water conserving measures such as:

  • Planning and design that matches plants to the site
  • Water-efficient plant materials, especially native plants
  • Efficient irrigation systems including drip irrigation
  • Use of water-conserving mulch or densely planted gardens
  • Soil preparation only if necessary
  • Appropriate turf since it can be very water consuming

Something to remember: a xeric garden can still be a beautiful garden. It will just require less water over time so it’s a win, win situation.

Xeric garden at the Arboretum

Habitat

A habitat garden is a garden that mimics the natural landscape while also providing food, shelter and potentially water for wildlife, including pollinators. A habitat garden has layers of plants and a succession of blooms. It is a very intentional way of landscaping focused more on giving back rather than taking something from your landscape. Don’t get me wrong, a habitat garden can still be beautiful, but it will certainly give you much more enjoyment as you attract a host of pollinator, birds and other wildlife to your yard.

Stratification

One of the most interesting processes I learned when I first started working at the Arboretum was the process of stratification. It intrigued me that I could collect seed from the wild and get it to germinate in the greenhouse simply by simulating the chilling and warming that seeds would endure if left outdoors for the winter in their native climate. This chilling and warming that seeds are exposed to breaks down natural germination inhibitors until they are ready and able to germinate the next year.

This process is so important for plants and their survival because it keeps seeds from germinating the same year of development. They must go through a cold period such as winter before they are able to germinate. This does two important things: keeps seeds from germinating in the fall and allows the seeds to be worked into the soil over the winter with the natural freeze/thaw of the soil so they can germinate in spring.

If a seed would germinate in the fall, that tiny plant would not have enough time to develop a sustaining root system. The tiny seeding would not survive the winter. The natural process allows a seed to lay dormant all winter and germinated in the spring when conditions are more favorable for survival, it would have the entire growing season to develop a healthy root system.

This process of stratification is why we encourage people to scatter prairie wildflowers and grass seed in November and December. It allows time for this process to occur so the seeds will germinate the following year.

Hopefully, this is helpful. I will discuss some other terms in upcoming blogs.

2005 seed mix of wildflowers and grasses scattered on the Prairie Window Project at the Arboretum

Beyond Milkweed: More Plants for Monarchs

I recently read an interesting article about monarch butterflies and their migration needs. The foundation of any successful monarch migration rests on a sufficient supply of native milkweeds, as these are the only plants monarch caterpillars can eat. However, there is ongoing research that suggests nectar plants besides milkweeds should receive more attention, since many milkweeds are done blooming when monarchs return to Mexico in the fall.        

Adult monarchs are generalist feeders, and they need varied nectar sources. This is why succession of bloom within your garden is so important.  A variety of beautiful wildflowers provide food for monarchs throughout the year, but also support many other butterflies, bees, birds and other wildlife. Yes, milkweeds are still critical to include in your design since they are both a host plant and a nectar source. But here are some other plants that will assist monarchs as they migrate:

Trees and Shrubs

  • Ceanothus americanus/herbaceous (New Jersey Tea) – Attractive clusters of white flowers in spring and early summer. 
  • Cephalanthus occidentalis (buttonbush) – Interesting white flowers May-September and beautiful fall color. Likes moisture and is great for heavy clay soils.
  • Prunus serotina  (Black Cherry) – Long clusters of fragrant white flowers in spring.  Large tree with fruit for birds later in the season.
  • Rhus spp. (sumac) – Shrubs or small trees with useful flowers for pollinators, fruit for other wildlife and good fall color. 
  • Heptacodium miconioides (Seven-son Flower) – Small ornamental tree with flowers in September.  Monarchs have flocked to our trees while in bloom. 
  • Sambucus canadensis (Elderberry) – Creamy white flowers in the summer atop this large wetland shrub.
  • Lindera benzoin (Spicebush) – Yellow-green flowers in the early spring.  Shrub with fragrant foliage and nice yellow fall color.    
  • Ribes odoratum (Clove Currant) – Bright yellow spicy scented flowers in April-May, followed by delicious black berries. It makes a nice understory shrub.
Monarchs on Seven Son Flower by Gerry Epp

Perennials other than Milkweeds

  • Symphyotrichum novae-angliae (New England Aster) – Purple, pink and lavender blooms September and October are extremely important nectar sources for adult monarchs.
  • Other Aster species: Aromatic Aster, Sky blue Aster, and Heath Aster
  • Solidago sp. (Goldenrod sp.) – Bright yellow blooms in the late summer through early fall. 
  • Vernonia lettermanii ‘Iron Butterfly’ (Ironweed) – Deep purple blooms in August and September.
  • Liatris sp. (Blazing Star) – Purple blooms on these diverse native perennials are a favorite of pollinators.
  • Echinacea sp. (Coneflowers) – These summer blooming wildflowers provide a perfect landing pad for monarchs and pollinators of all sorts. The seeds are eaten by birds through the winter. 
  • Pycnanthemum sp. Mountain Mint – These spreading wildflowers are usually covered with pollinators of all kinds when they bloom in the summer. Give them room in the garden because they do roam. 
  • Monarda sp. (Beebalm) – Fragrant foliage and bright pinkish blooms attract a host of pollinators. 
Monarch on New England Aster
Monarch on late blooming Swamp Milkweed. Photo by Barbara Beesley

Fuel for the Flight

Again, monarchs need milkweeds. These plants are vital to their reproductive processes. However, they need other nectar-rich wildflowers too. This is one of the weak points in their return migration journey.  As they migrate south in the fall, they are not reproductive. Their goal during this part of the migratory cycle is to fuel up on late season nectar plants and build up their body fat so they can make it to Mexico and survive the winter. There, in early March of the following spring, they will leave their mountain roosts to mate, lay eggs on milkweed, and start the cycle all over again.

It is so important to provide fuel and sustenance for Monarchs and other pollinators. Available milkweeds, nectar plants, along with water, trees or other protection at night for roosting and connected habitats will help them all along the way – south to north and back again.

Linking the continental migratory cycle of the monarch butterfly to understand its population decline.