Plant Tags and USDA Plant Hardiness Zone Map

Posted on December 6, 2023 by Scott Vogt

Plant tags can be confusing. They give general information about the plant, but I often wonder, is this realistic for our area? Will this plant really grow to four feet tall? Or will it be beat down by our Kansas heat and wind? Can it withstand our temperature extremes? One critically important piece of information on the plant tag is the U.S. Department of Agriculture (USDA) Plant Hardiness Zone Map (PHZM).

*Echinacea purpurea ‘Pow Pow White’ is hardy to zone 3 (-40 to -35 degrees F). So it will grow well in zones 3-8, which is most of the United States.*

Purpose and Use

The USDA Plant Hardiness Zone Map was developed to show the average low winter temperature. Plants are rated according to the USDA hardiness zones, which is the minimum winter temperature they can survive. On the map, there are 13 zones with a 10-degree F difference between the zones. Each zone is further delineated with 5-degree F differences dividing the zone further into a and b (6a and 6b for example). Hesston is in zone 6b (-5 to 0 degrees F).

Kansas hardiness zones range from 5b (-15 to -10 degrees F) in the extreme northwest corner to 7a (0 – 5 degrees F) in the south and southeast. The USDA PHZM has been recently updated to show gardeners what plants are most likely to survive in their area. Type in your zip code to find your zone and use it as you choose plants for your landscape. CLICK HERE FOR THE 2023 USDA PHZM

Plant Provenance

This hardiness zone map highlights another important factor to consider regarding native plants – provenance. Plant provenance refers to the source of the plant material that was collected for propagation. The reason this matters is that some species have very broad natural ranges that cover several very different ecoregions, hardiness zones. The populations of such species have developed adaptations to their environment at a genetic level even though they are outwardly identical. Seed collected from a northern provenance is adapted to a shorter growing season, colder winter temperatures and often cooler nighttime temperatures compared to a southern provenance seed. All this to say, try to purchase native seed from sources closest to your ecoregion as possible.

*This coleus is an annual unless it stays warm all year such as zone 10. Obviously, it must be kept away from freezing temperatures.*

Plant lovers tend to push the boundaries when it comes to hardiness. I have been told and shown plants growing in Kansas that are supposed to be hardy to zone 8. It’s possible, but they are the exception, not the rule. Often they are growing in a microclimate, which is a localized area that differs from the average climate with different growing conditions. This could be on the side of a building, red brick wall, a fence or an evergreen tree blocking the sun or wind. This could also be in a valley or on top of a hill.

The USDA Plant Hardiness Zone Map is a valuable tool that helps gardeners and growers choose hardy plants that are most likely to thrive at a location.

Here are a few other helpful pointers from the USDA:

If your hardiness zone has changed in this edition of the USDA PHZM, it does not mean you should start removing plants from your garden or change what you are growing. What has thrived in your yard will most likely continue to thrive.
Remember this is the average coldest night—not the lowest it could go. Gardeners should keep that in mind when selecting plants, especially if they choose to “push” their hardiness zone by growing plants not rated for their zone.
Microclimates, which are fine-scale climate variations, can be small heat islands—such as those caused by blacktop and concrete—or cool spots (frost pockets) caused by small hills and valleys. No hardiness zone map can take the place of the detailed knowledge that gardeners learn about their own gardens through hands-on experience.
Many species of perennial plants gradually acquire cold hardiness in the fall when they experience shorter days and cooler temperatures. This hardiness is normally lost gradually in late winter as temperatures warm and days become longer. A bout of extremely cold weather early in the fall might injure plants even though the temperatures may not reach the average lowest temperature for your zone. Similarly, exceptionally warm weather in midwinter followed by a sharp change to seasonably cold weather may cause injury to plants as well. Such factors could not be taken into account in the USDA PHZM.
All PHZMs should serve as general guides. They are based on the average lowest temperatures, not the lowest ever. Growing plants at the extreme range of the coldest zone where they are adapted means that they could experience a year with a rare, extreme cold snap. Even if it lasts just a day or two, plants that have thrived happily for several years could be lost. Gardeners need to keep that in mind and understand that past weather records cannot provide a guaranteed forecast for future variation in weather.

Other Factors Affecting Plant Survival

Many other environmental factors, in addition to hardiness zones, contribute to the success or failure of plants. Wind, soil type, soil moisture, humidity, pollution, snow, and winter sunshine can greatly affect the survival of plants. The way plants are placed in the landscape, how they are planted, and their size and health might also influence their survival.

Light: To thrive, plants need to be planted where they will receive the proper amount of light. For example, plants that require partial shade that are at the limits of hardiness in your area might be injured by too much sun during the winter because it might cause rapid changes in the plant’s internal temperature.
Soil moisture: Plants have different requirements for soil moisture, and this might vary seasonally. Plants that might otherwise be hardy in your zone might be injured if soil moisture is too dry in late autumn and they enter dormancy while suffering moisture stress.
Temperature: Plants grow best within a range of optimal temperatures, both cold and hot. That range may be wide for some varieties and species but narrow for others.
Duration of exposure to cold: Many plants that can survive a short period of exposure to cold may not tolerate longer periods of cold weather.
Humidity: High relative humidity limits cold damage by reducing moisture loss from leaves, branches, and buds. Cold injury can be more severe if the humidity is low, especially for evergreens.

On Weeding: Process over Perfection

Posted on September 28, 2023 by Janelle Flory Schrock

My mom was serious about weed pulling. Especially after she retired, one could often find her out in her yard pulling weeds for hours at a time. Since I didn’t consider myself much of a gardener at the time, I didn’t really understand why she would spend so much time on what seemed, to me, to be a very mundane and laborious task.

It wasn’t until she entered the later stages of a terminal illness that I understood what a solace it was for her, a way to feel a sense of control over something, however small or futile it may have seemed to others.

Now that I have begun to develop a meaningful relationship with my yard, I find myself starting to “channel my inner Mom”. I have a semi-regular routine of going out to my front lawn to pull weeds from an ever-expanding patch of buffalo grass. In this practice, I have learned that weeding is an act of focused intention. And though it is also an act of exerting control over the land, if paired with an intention to learn from and respond to the plants themselves, this control can be moderated by care.

Staminate spikelets (male flowers with pollen)

This weeding routine began two years ago, when I noticed a few buffalograss seedheads poking up through our polyculture lawn. Five or six years prior, we had felled an aged maple tree. Since then, the area in front of our house has formed a natural matrix of dandelions, clover, bermudagrass, foxtail and bindweed. But apparently, at some point there had been some buffalo grass, which was now emerging again. I wanted more of it and less of those other things.

I felt overwhelmed by the idea of using chemicals to kill the existing vegetation in order to have a clean slate for seeding. Instead, inspired by long-time Arboretum volunteer and mentor Lorna Harder, I began mimicking her strategy of pulling the undesired plants to give the buffalo grass a chance to propagate.

July 2023 – north side of front yard. The spring and summer brought sporadic, but well-timed rain events.

Most people probably wouldn’t choose this strategy for establishing a lawn. Whether it’s because of other demands on their time or a personal preference, most will opt for a more straight-forward approach with a predictable timeline, as recommended by my colleague Scott, or the Kansas State University Turf Management folks. I have decided that for me, it’s more about the process than the product. I consider weeding a part of my self-care routine, one that also benefits the ecosystem of my yard. Each year, as I take stock of how much ground was covered (pun intended), I am motivated to choose which area I’d like to work on next.

If this type of approach to gardening appeals to you as well, but feels too daunting, I would like to offer some encouragement that I recently received from one of our members. Try not to focus on all there is still left to do. Remember to look at all the progress you have already made.

Something to ponder while I continue my daily weeding.

*My spouse Jon clears bermudagrass and other vegetation from the perimeter of a seeded patch of buffalo grass in our back yard.* *As with the front, this area had been heavily shaded by a large tree and needed a cover crop.*

Summer Garden Checklist

Posted on July 27, 2023 by Scott Vogt

Kansas summers can discourage even the hardiest gardeners. However, taking time to manage your garden now will help your garden later. Here’s my Summer Garden Checklist for the Kansas gardener.

Control Warm Season Weeds

Summer brings with it a new set of weeds to control. Hot weather germinates summer annuals like crabgrass, foxtail. Nutsedge and other weeds invade your lawn and landscape as well. Manage weeds using nonchemical methods such as cultivation, hand weeding, or mowing; use toxic chemicals as a last resort.

Mowing regularly and occasionally edging along sidewalks and walkways is needed to ensure your lawn is not overrun with weeds. In a landscaped bed, hand pull any of these weeds, especially if they have seed heads. It is so important to not let these weeds go to seed. Stay vigilant even though the summer heat tries to squash your enthusiasm. A little extra effort now will make your garden better this fall and into next year.

*Crabgrass in tree mulch ring controlled with roundup: one treatment should clean up the mulched area and keep it weed free the rest of the season.*

Be Water Wise

To reduce evaporation, water when temperatures are cooler and air is still, usually in the early morning. Water deeply to moisten the root zone, but infrequently. About an inch of water each week is a good rule of thumb! If you have invested in container plants, they will need daily watering, as soil in pots can dry out quickly and damage plant roots on hot summer days. Each of our gardens have indicator plants that show stress first, let these plants be your guide as when to water. For new planting started this spring, water when the top one to two inches of soil is dry. Remember it takes three to five years for sustaining roots systems to develop for most native plants. Supplemental watering is necessary to encourage growth and root development in these young plants.

*We use pressure compensating 1/2 inch soaker hoses to efficiently water trees, shrubs and a few flower beds. Each emitter puts out 1 gallon of water per hour.*

Prepare for seeding

If you are wanting to establish native prairie plants from seed, now is a great time to prepare your area. Mow your area short (1-2 inches). Control perennial weeds such as bindweed or Bermuda grass by carefully spraying the area with Roundup. It will take several applications to get these problematic weeds under control. If you can see soil, tillage is not necessary. If you can’t see soil, till lightly to expose some bare soil. Remember, each time you till, you bring up more weed seeds, so tread lightly.

Measure your area and order a seed mixture that matches your site. A good seed mix ratio of wildflower to grass is 70% wildflowers to 30% grasses. Grasses tend to dominate over time, so this ratio will give the wildflowers a good start. We typically spread seed in November and December after the soil temperature has dropped enough to discourage germination. The natural freeze/thaw of the ground will work the seeds down into the soil to the proper depth for germination next spring.

*This is the seed mix we established along our newly renovated path.*

Sidewalk edge planting: We mixed some sand with the seed mix to make it easier to distribute. We then let the natural freeze/thaw of the soil plant the seed for us through the winter. Germination occurred the following spring when soil temperatures rose above 60 degrees.

Trim

Now is a great time to trim back perennials that have become unruly. Perennial and grasses that are encroaching sidewalks, paths, and structures can be sheared back to size. If this is a problem every year, you may consider moving the taller plants to another spot. Plants can be divided next February or March before they start to actively grow.

Low hanging branches from trees can also be pruned. It is getting late in the season to do much pruning on shrubs. New growth may not have enough time to get hardened off before cooler/colder weather. If a branch or shoot is in the way, then prune it, but prune sooner rather than later. If you can wait until the shrub goes dormant this fall, then wait.

As a general rule, early spring flowering shrubs such as forsythia, lilac and spirea should be pruned right after they are done blooming since they bloom on the previous year’s growth. Pruning right after blooming will allow the shrub to grow and develop a new set of buds for the next spring.

*A large compass plant that needs to be trimmed away from the path.*

Finally, remember “WHY” you are gardening; creating habitat, conserving water, aesthetics, attracting pollinators, attracting birds and other wildlife or curb appeal. Let your “WHY” reinvigorate you to take care of a few extra tasks that will give your landscape a boost. Don’t sweat the small stuff and don’t forget to step back to enjoy what you are trying to create. If it is all work and no enjoyment, then what is the point.

*Pale purple coneflower with a common buckeye butterfly. Fun to watch!*

Garden Spotlight: Backyard Meadow in North Newton

Posted on October 19, 2022 by Janelle Flory Schrock

At FloraKansas it’s always a pleasure to hear from members who are renovating an entire landscape in
native and adaptable plants all at once. Dramatic transformations have a wow factor about them, with the instant gratification of an “extreme makeover”. However, so many Dyck Arboretum members have been tending and transforming their gardens over several years or even several decades. This is the case with Ron Flaming’s backyard meadow.

As a Harvey County Master Gardener, Ron’s front garden is immaculate. A well-tended quarter acre of lawn is framed by several foundation beds of carefully-selected shrubs and groundcovers. A small planting of wildflowers surround a weeping understory tree at the curb. But it’s the back garden that really takes you on a native plant journey.

*A rock garden, including a water feature, bird feeders and a river birch, frames the foreground, while the bridge and gate to the meadow draw the visitor further into the backyard.*

Several river birch trees surround a puddling water feature and a rock garden by the patio. A few hummingbird feeders round out this pollinator sheltering space. Just a step beyond the rock garden, a small bridge flanked by formal native plantings, leads you to an arbor and a winding path through a meadow planting.

At the time I visited in early June, the meadow featured mixed-grass prairie species. I was able to recognize little bluestem, side oats grama and prairie dropseed, as well as a smattering of wildflower blooms mixed in: common milkweed, penstemon, and baptisia. Several complementary non-natives like delphinium gave a
nice pop of color as well. The path curved around the back side of a rustic garden shed. Behind the shed is a rare wooded microclimate, which allows understory shrubs and woodland wildflower species to thrive.

Ron’s many-layered meadow garden gives me hope as I grapple with my own yard. Once shaded by an 80-year-old American Elm, my backyard now bakes in full sun, presenting a new challenge. But I am inspired by Ron and am reminded that it’s amazing what a gardener can accomplish over the years with a lot of persistence, creativity and grace.

The act of curating an inviting outdoor space for oneself, one’s family and for wildlife is something I’d like to draw attention to over a series of “Kansas Garden Success Stories” to share with our followers. If you are a member of the Arboretum who would like to share the story of your garden and your journey with Kansas native plants, please send me a message at arboretum@hesston.edu with the subject line, “Garden Spotlight”.

Defining Sun Requirements for Native Plants

Posted on December 23, 2020 by Scott Vogt

Knowing how much light a plant needs to thrive should be a simple question, but it is often easily misunderstood. There are so many different descriptions for sun requirements or exposure found on plant labels, but they don’t provide all the information you may need to make the right selection for your yard. Are these descriptions for Kansas or Virginia? Can a plant survive in full sun with 30 inches of average rainfall or does it need 50 inches? Does it need full sun with protection from the hot afternoon sun?

Plant labeling has been getting better and more consistent, so understanding a few key terms will assist in selecting the right plant for your landscape conditions. Let’s take a closer look.

Terminology

Every plant in the landscape needs sunlight to grow. Even shade plants with their adaptations need a certain amount of light to grow and prosper. Plant labels identify the amount of sun a plant requires as full sun, part sun, part shade full shade, or dense shade:

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
Dense shade – No direct sunlight and little indirect light reaches the ground.

A Closer Look at the Terms

Full Sun

Most prairie plants fall into this category of sunlight exposure. This light is bright, sunny for most of the day like in open areas and backyards. These spaces get at least six hours of direct sunlight and need to be planted with full sun plants. Their deep roots and natural adaptations for direct sunlight will help them thrive in this harsh environment. Silver or gray leaves, pubescent leaves, or leaf orientation are adaptations that help them prosper in these sunny areas.

There are other plants that appreciate some protection from the hottest part of the days, but they still need at least six hours of direct light. Keep in mind that full sun in the Smoky Mountains and full sun in Texas are different. So, think critically about your local site, because some experimentation may still be needed.

Part Sun and Part Shade

When I think about part sun and part shade, savannah plants come to mind. They are tucked up close to the margins of the forest. They transition from prairie plants to woodland plants. Some will get sunlight for most of the day, but not often. It is not the hottest direct sun.

Part sun and part shade are very similar, but there are subtle differences. These two terms can be understood quite differently. Most plants requiring either part sun or part shade do well in filtered light for most of the day. In Kansas, a plant requiring part sun or part shade needs to be protected from the more intense afternoon sun. Give it morning sun to keep it happy.

Plants requiring part shade can be quite sensitive to too much direct sun, particularly in the afternoon, and will need shade during the hottest parts of the day.

Plants requiring part sun can usually tolerate more light and need a minimum amount of direct sun to thrive. These plants may bloom poorly if given too little sun.

For either group, providing a few hours of direct morning sun is a good choice.

Bumblebee on Echinacea purpurea-Purple coneflower appreciates partial sun conditions
photo by Janelle Flory Schrock

Full Shade

Plants requiring full shade are the most challenging in Kansas. Essentially, we are trying to grow shade plants in a prairie environment with lots of sun and inconsistent moisture. Shaded areas typically stay dry and need supplemental moisture to grow full shade plants. Full shade plants require anything less than three hours of direct light such as morning sun and late evening sunlight. Protection from the hot midday sun is very important. Filtered light, such as that found beneath a tree canopy, is a good setting for full shade plants. This type of light is referred to as dappled shade and offers many gardening opportunities.

*Native columbine thriving in the shade of an elm tree*

Dense Shade

Dense shade may occur under a dense evergreen tree against a fence, or the north side of your house protected by a deck. These areas get little if any sunlight throughout the day. These problem areas are usually dark and can stay very wet or very dry. There is not much you can do under these conditions, but maybe a ground cover or decorative yard element would be a good choice. Plants need some light and you are fighting nature by trying to grow something without much light. Rather focus on the areas that do have some light to draw your eyes away from this area.

It is best to become familiar with sun exposure in your landscape by checking on light conditions throughout the day and over the course of a full growing season. Growing plants in Kansas can be a test of your will, so match plants up to your landscape based on light conditions in your landscape. I have found that if you get this requirement right, some of the other elements like soil, water and fertility will sort themselves out on their own.

How to Add Native Plants to an Established Prairie

Posted on September 30, 2020 by Scott Vogt

As we wind down the growing season, now is a great time to take stock of your new prairie garden or established prairie landscape. Which plants have done well? What has struggled? What needs to be moved? Which plants need to be added? These questions will help guide your efforts this fall and especially next season.

If you have an established prairie, it can be challenging to make some desired changes. To add a few plants to a mature landscape takes some forethought and planning. The deep rooted natives have a distinct advantage over the immature perennial you are trying to get started. Here are a few simple steps to help give these new plants a fighting chance.

Choose spots

Maybe you want to add some wildflowers into a prairie setting dominated by native grasses. Visualize where you want these new plants. Remember, a prairie has subtle splashes of color. Sprinkling in a handful of wildflowers will look more natural.

*This couple is slowly adding a few native wildflower into their meadow. Some have even started coming in on their own.*

Prepare the soil

With your spots chosen, now it is time to make room for these additions to your prairie. We flag the spots and then spray them with Roundup. These spots are usually not more than one foot in diameter. If you want to avoid spraying, cut the area down to the ground and cover it with heavy cardboard for several months or over winter. Secure these one foot areas with several inches of mulch or stones.

Two or three inches of mulch will hold down the cardboard and smother out the existing plants.

Choose the right plant

I keep circling back to this point because it is so important. If plants have struggled in an area, it is usually because either the soil or the plant is out of balance. Typically, the soil is not to blame. It is more likely that the soil and plant have not been correctly matched. Observe soil, sun and drainage issues and match the proper plant to your area. It is good to have a sense of how some of these natives grow naturally in community. The more you know, the more successful you will be.

Establish your plants

After waiting several months or over winter, it is now time to plant. Establish plants using this method in either spring (April/May) or late summer (August/September). If you sprayed the small areas, you can simply plant right into the open weed free soil. If you put down cardboard and covered it with mulch, you can pull back a little of the mulch and slice through the cardboard. Put the plants into the ground and water daily. Leave the cardboard and mulch to decompose over the next few years, as this will give the new plants a little room to grow with less competition. The cardboard and mulch will ultimately disappear.

Next Steps

Over the next few years, it will be necessary to monitor these new plants. It generally takes two to three years for the root systems to get fully established. Remember to:

Water deeply as needed.
Make sure they are not getting too crowded by other vegetation.
You may need to cut back nearby grasses so these new plants get enough sunlight. This will only be necessary during this establishment phase.

*Native grasses are wonderful but a few wildflowers in the prairie make it even more beautiful and dynamic.*

This process is not guaranteed to succeed, but we have used it successfully to add some diversity to an established prairie. This approach can also be used to transform a smaller intensively planted display bed. Either way, plan now so you are ready to plant next season.