Field Trip: Lady Bird Johnson Wildflower Center, part one

Last week my place of employment sent me to Austin, Texas to spend some time at the Lady Bird Johnson Wildflower Center. I was there for a native plant conference put on by the American Public Garden Association. I had been wanting to visit the Wildflower Center for a long time, so it was great to finally get the chance. Their gardens are truly amazing. I spent three days there, but could have easily stayed much longer. The native plant conference was great, too. I learned a lot about native plant horticulture, and I left feeling inspired to put those things into practice. If you are wondering “why native plants?,” the Wildflower Center has a good answer to that on their website.

While I was there I took dozens of photos, so I am sharing some of those with you in a two part post. The plant name following each photo or series of photos links to a corresponding entry in the Native Plant Database which is managed by the Wildflower Center’s Native Plant Information Network. The quotes that accompany the plant names are taken from the Native Plant Database entries.

Sophora secundiflora (Texas mountain laurel). “The fragrance of Texas mountain laurel flowers is reminiscent of artificial grape products.”

Ranunculus macranthus (large buttercup). “This is one of the largest flowered native buttercups. The large butter-yellow flowers and attractive foliage of this plant immediately attract the eye.”

echinocereus reichenbachii 3

Echinocereus reichenbachii (lace cactus). “Lace cactus is unpredictable in its development, one plant forming a single stem, while its neighbor may branch out and form a dozen or more.”

Dalea greggii (Gregg’s prairie clover). “Grown mostly for its silvery, blue-green, delicately compound leaves, the shrub is awash with clusters of tiny, pea-shaped, purple flowers in spring and early summer.” 

viburnum rufidulum 5

Viburnum rufidulum (southern blackhaw). “In Manual of the Vascular Plants of Texas, Correll and Johnston noted that the fruit tastes similar to raisins.”

mahonia trifoliata 5

Mahonia trifoliolata (agarita). “Songbirds eat the fruits, and quail and small mammals use the plant for cover. It is considered a good honey source.”

lady bird johnson quote

How Pitcher Plants Eat Bugs (Frog Optional)

SAMSUNG

A few months ago at work I captured this photo of a frog inside of a pitcher plant. Do you see it? It is pretty well camouflaged and poking its head out just enough to intercept curious insects lured in by the promise of nectar, eating them before they can make their way into the tube. Either way, approaching insects are about to meet their fate. Whether by plant or by frog, they are destined to be consumed lest they turn away in time.

This frog was hiding inside the modified leaf of a species of Sarracenia, a carnivorous plant commonly known as a North American pitcher plant. There are at least eight species of Sarracenia, all of which naturally occur in the southeastern region of the United States. One species, Sarracenia purpurea, also occurs in the northeast, the upper Midwest, and throughout much of Canada. Sarracenia is in the family Sarraceniaceae along with two other genera of pitcher plants, Darlingtonia (the cobra plant, native to northern California and southern Oregon) and Heliamphora (the sun pitchers, native to South America). Plants in this family are not to be confused with the distantly related tropical pitcher plants which are in the genus Nepenthes (family Nepentheaceae).

The natural habitats of Sarracenia are sunny, open areas that remain permanently wet, including meadows, savannahs, fens, and swamps. The soils are acidic, nutrient poor, and typically composed of sandy peat commonly derived from sphagnum moss. In the southeast, less than 5% of the original (pre-European settlement) Sarracenia habitat remains, threatening its survival in the wild. Sarracenia oreophila (green pitcher plant) is currently listed as critically endangered on the IUCN Red List.

Flowering occurs in the spring, usually before pitchers form. Individual flowers are formed on tall stalks that rise straight up and then bend at the very top, hanging the flower upside down. Early flowering and tall flower stalks help prevent pollinating insects from being consumed by the plant. In his book The Savage Garden, Peter D’Amato describes the flowers as “showy, brilliant, and very unusual – a wonderful bonus to an already handsome class of foliage plants.” The flowers are either yellow or a shade of red and last about two weeks, after which the petals drop and a seed pod forms. Seeds are released from the fruits in the fall.

Flower of Sarracenia rubra (sweet pitcherplant) - photo credit: www.eol.org

Flower of Sarracenia rubra (sweet pitcher plant) – photo credit: www.eol.org

D’Amato writes that Sarracenia are among the “most ravenous” plants, with each leaf having the potential of trapping “thousands of nasty insects.” In some cases pitchers even flop over, heavy with the weight of bugs inside them. The specifics of capturing and killing insects varies between species of Sarracenia, but in general prey is lured to the opening of the pitcher with a combination of nectar, scent, and color. Upon entering the tube, gravity, waxy surfaces, drugs, and hairs force the captives downward where they are eventually consumed by enzymes and microbes. Digested insects provide the plant with nutrients necessary for growth – nutrients that otherwise are taken up by the roots of plants that occur in more nutrient rich soils.

Sarracenia purpurea (purple pitcher plant) is unique in that its pitchers lack a “hood” or “lid” – a standard feature of other species of Sarracenia that helps keep rain from entering the pitchers. Instead, the pitchers fill with water and insects are killed by drowning. The most brutal killer is probably Sarracenia psittacina (parrot pitcher plant) which has an additional opening inside of its pitcher. The opening is small and difficult to find again once an insect is on the wrong side of it. The inside walls of the pitcher are covered in long, sharp, downward pointing hairs, and the struggling insect is pierced repeatedly by the hairs as it makes its way to the bottom of the tube to be digested.

Hoodless pitchers of Sarracenia purpurea (photo credit: www.eol.org)

Hoodless pitchers of Sarracenia purpurea (photo credit: www.eol.org)

Hooded pitchers of Sarracenia leucophylla (photo credit: www.eol.org)

Hooded pitchers of Sarracenia leucophylla (photo credit: www.eol.org)

According to D’Amato, “the Sarracenia are one of the simplest carnivorous plants to grow, and certainly among the most fun and rewarding.” Learn more about growing North American pitcher plants by consulting D’Amato’s book and/or by visiting the website of the International Carnivorous Plant Society.

Want to learn more about Sarracenia? The Plants are Cool, Too! web series has a great video about them:

Other carnivorous plant posts:

Year of Pollination: The Anatomy of a Bee

A greater appreciation for pollinators can be had by learning to identify them – being able to tell one from another and calling them by name. Anyone can tell a butterfly from a bee, but how about telling a sweat bee from a leafcutter bee? Or one species of sweat bee from another species of sweat bee? That takes more training. This is where knowing the parts of a bee becomes important.

I am new to learning the names of pollinators. I’ve been learning the names of plants for many years now (and I still have a long way to go), but my knowledge of insect identification is largely limited to one entomology course I took in college and the occasional reading about insects in books and magazines. So, this post is just as much for me as it is for anybody else. It also explains why it is brief and basic. It’s for beginners.

This first illustration is found in the book Pollinators of Native Plants by Heather Holm. The book starts with brief overviews of pollination, pollinators, and pollinator conservation, but then spends nearly 200 pages profiling specific plants and describing the particular species of pollinating insects that visit them. The photos of the insects are great and should be very useful in helping to identify pollinators.

bee anatomy_pollinators of native plants book

This next illustration is from the book California Bees and Blooms by Gordon W. Frankie, et al. The title is a bit deceptive because much of what is found in this book is just as applicable to people outside of California as it is to people within. There is some discussion about plants and pollinators specific to California and the western states, but there is also a lot of great information about bees, flowers, and pollination in general, including some great advice on learning to identify bees. The book includes this basic diagram, but it also provides several other more detailed illustrations that help further describe things like mouth parts, wings, and legs.

bee anatomy_california bees and blooms book

As part of their discussion on identifying bees, the authors of California Bees and Blooms offer these encouraging and helpful words to beginners like me: “Even trained taxonomists must examine most bees under a microscope to identify them to species level, but knowing the characteristics to look for can give you a pretty good idea of the major groups and families of bees that are visiting your garden. These include size, color, and features of the head, thorax, wings, and abdomen.”

If you would like to know more about the pollinators found in your region, including their names, life history, and the plants they visit, books like the aforementioned are a good start. Also, find yourself a copy of a field guide for the insects in your area and a good hand lens. Then spend some time outside closely and quietly observing the busy lives of the tiny things around you. I plan to do more of this sort of thing, and I am excited see what I might find. Let me know what you find.

Here are a few online resources for learning more about bee anatomy and bee identification:

Other “Year of Pollination” Posts:

Plants Use Mycorrhizal Fungi to Warn Each Other of Incoming Threats

The March 2015 issue of New Phytologist is a Special Issue focusing on the “ecology and evolution of mycorrhizas.” This is the second of two articles from that issue that I am reviewing. Read the first review here.

Interplant signalling through hyphal networks by David Johnson and Lucy Gilbert

When an individual plant is attacked by an insect or fungal pest, it can warn neighboring plants – prompting them to produce compounds that either repel the pests or attract beneficial organisms that can fight off the pests. There are two main pathways for a plant to send these communications: through the air by way of volatile organic compounds (VOC’s) or through the soil by way of a vast collection of fungal hyphae called mycelium. Plant communication by aerial release of VOC’s has been well documented; communication via mycelium, however, is a fairly recent discovery, and there is much left to learn.

“The length of hyphae in the soil and the ability of mycorrhizal fungi to form multiple points of entry into roots can lead to the formation of a common mycelial network (CMN) that interconnects two or more plants.” These CMN’s are known to play “key roles in facilitating nutrient transport and redistribution.” We now understand that they can also “facilitate defense against insect herbivores and foliar necrotophic fungi by acting as conduits for interplant signaling.” The purpose of this research is to explore the “mechanisms, evolutionary consequences, and circumstances” surrounding the evolution of this process and to “highlight key gaps in our understanding.”

interplant signaling

An illustration of plant communication (aka interplant signaling) by air and by soil form the article in New Phytologist.

If plants are communicating via CMN’s, how are they doing it? The authors propose three potential mechanisms. The first is by signal molecules being transported “in liquid films on the external surface of hyphae via capillary action or microbes.” They determine that this form of communication would be easily disrupted by soil particles and isn’t likely to occur over long distances. The second mechanism is by molecules being transported within hyphae, passing from cell to cell until they reach their destination. The third mechanism involves an electrical signal induced by wounding.

If signal molecules are involved in the process, what molecules are they? There are some molecules already known to be transported by fungal hyphae (lipids, phosphate transporters, and amino acids) and there are also compounds known to be involved in signaling between plants and mycorrhizal fungi. Exploring these further would be a good place to start. We also need to determine if specific insect and fungal pests or certain types of plant damage result in unique signaling compounds.

It has been established that electrical signals can be produced in response to plant damage. These signals are a result of a process known as membrane depolarization. “A key advantage of electrical-induced defense over mobile chemical is the speed of delivery.” Movement of a molecule through cells occurs significantly slower than an electrical charge, which is important if the distance to transport the message is relatively far and the plant needs to respond quickly to an invasion. Various aspects of fungal physiology and activity have been shown to be driven in part by membrane depolarization, so involving it in interplant signaling isn’t too far-fetched.

photo credit: wikimedia commons

photo credit: wikimedia commons

How and why does a system of interplant communication involving mycorrhizal fungi evolve? And what are the costs and benefits to the plants and fungi involved? Determining costs and benefits will depend largely on further establishing the signaling mechanisms. Exploring real world systems will also help us answer these questions. For example, in a stable environment such as a managed grassland where CMNs are well developed, a significant loss of plants to a pest or disease could be devastating for the mycorrhizal community, so “transferring warning signals” would be highly beneficial. Conversely, in an unstable environment where a CMN is less established, assisting in interplant signaling may be less of an imperative. Regarding questions concerning the degree of specialization involved in herbivore-plant-fungal interactions: if a “generic herbivore signal” is sent to a neighboring plant that is not typically affected by the attacking herbivore, the cost to the plant in putting up its defenses and to the fungus in transporting the message is high and unnecessary. So, in an environment where there are many different plant species, species-specific signals may be selected for over time; in areas where there are few plant species, a generic signal would suffice.

As research continues, the mysteries of “defense-related” interplant communication via CMN’s will be revealed. Field studies are particularly important because they can paint a more accurate picture compared to “highly simplified laboratory conditions.” One exciting thing about this type of communication is that it may mean that some plants are communicating with each other across great distances, since “some species of fungi can be vast.” CMNs can also target specific plants, and compared to communication via aerial VOC’s, the signal will not be diluted by the wind.

Since I am in the process of reading Robin Wall Kimmerer’s book, Braiding Sweetgrass, I have decided to include her description of a tree-mycorrhizal fungi relationship:

The trees in a forest are often interconnected by subterranean networks of mycorrhizae, fungal strands that inhabit tree roots. The mycorrhizal symbiosis enables the fungi to forage for mineral nutrients in the soil and deliver them to the tree in exchange for carbohydrates. The mycorrhizae may form fungal bridges between individual trees, so that all the trees in a forest are connected. These fungal networks appear to redistribute the wealth of carbohydrates from tree to tree. A kind of Robin Hood, they take from the rich and give to the poor so that all the trees arrive at the same carbon surplus at the same time. They weave a web of reciprocity, of giving and taking. In this way, the trees all act as one because the fungi have connected them. Through unity, survival. All flourishing is mutual.

Using Plant Root and Mycorrhizal Fungal Traits to Predict Soil Structure

The March 2015 issue of New Phytologist is a Special Issue exploring the “ecology and evolution of mycorrhizas.” A mycorrhiza is a symbiotic association between a fungus and the roots of a plant. The introductory editorial of this special issue asserts that “almost all land plant species form a symbiosis with mycorrhizal fungi.” Generally, the association benefits both plant and fungus. The plant gains greater access to water and mineral nutrients by the way of fungal hyphae, and the fungus recieves carbohydrates (glucose and sucrose) that have been synthesized in the leaves of the plant and transported down into its roots. We have been aware of this relationship since at least the middle of the 19th century, but recent advances in technology have given us new insight into just how extensive and important it is . “Plants cannot be considered as isolated individuals anymore, but as metaorganisms or holobionts encompassing an active microbial community re-programming host physiology.”

However, there are still “critical gaps” in our understanding of mycorrhizas, hence the special issue of New Phytologist. In this issue they endeavor to address the following questions: “How is the balance of mutualism maintained between plants and fungi? What is the role of mycorrhizal fungi in the soil ecosystem? What controls fungal community composition, and how is diversity maintained?” There is so much more to learn, but the research presented in this issue has us moving in the right direction. If you are interested in this sort of thing, I encourage you to check out the entire issue. I have picked out just 2 of the 32 articles to present here – one this week and the other next week.

photo credit: wikimedia commons

photo credit: wikimedia commons

Plant root and mycorrhizal fungal traits for understanding soil aggregation by Matthias C. Rillig, Carlos A. Aguilar-Trigueros, Joana Bergmann, Erik Verbruggen, Stavros D. Veresoglou, and Anika Lehmann

Soil structure is determined by the size, shape, and extent of soil aggregates and the resulting pore spaces found between them. The arrangement of soil aggregates and pore spaces helps determine the availability and movement of water and air and also has an influence on the growth and movement of micro- and macroorganisims, including fungi, plant roots, bacteria, and arthropods. The authors state that “soil aggregation is important for root growth and for a wide range of soil features and ecosystem process rates, such as carbon storage and resistance to erosion.”

Soil aggregates are composed mainly of clay particles, organic matter (including plant roots), organic compounds (produced by bacteria and fungi), and fungal hyphae. There has been plenty of research on soil aggregation, but much of it is focused on management practices and physical chemical factors. Less is known about the contribution of plant roots and mycorrhizal fungi to the formation and stabilization of soil aggregates. We know they play a role, but we lack understanding about the extent to which soil aggregation can be predicted not just by abiotic factors but also by the presence of plants and mycorrhizal fungi. The authors of this paper propose a widespread, trait-based approach to researching this topic, recognizing that “summarizing ecological characteristics of species by means of traits has become an essential tool in plant ecology.”

Possible traits to be considered were grouped into two categories: formation-related traits and stabilization-related traits. Formation refers to “the initial binding together of particles” to form an aggregate. Stabilization is a process in which aggregates are “increasingly resistant to the application of disintegrating forces, such as water penetrating into pores.” These two processes (along with disintegration) are occurring simultaneously in virtually all soils, but they “may be executed by different organisms expressing different traits.” Some of the formation traits include length, extension ability, and relative growth of roots and hyphae; root and hyphae exudate quality and quantity; and the “ability of roots or hyphae to bring soil particles together by moving them, leading to potential aggregation.” Stabilization traits include tensile strength, density, and “entangling ability” of roots and hyphae; water repellency of the aggregates and cementation capability of the exudates; and the life span, palatability, and repair capacity of roots and hyphae.

photo credit: wikimedia commons

photo credit: wikimedia commons

The amount of time and effort it will take to measure the traits of each and every plant and mycorrhizal fungi species and to determine the extent to which those traits contribute to soil aggregation will be considerable. The authors acknowledge that “some of these traits will be relatively easy to measure,” while “others will be quite challenging.” However, as technologies advance, the mysterious world under our feet should become easier to explore. As the traits of each species of plant and fungi are measured, a database can be constructed and eventually used to determine the plant/fungi combinations that are the best fits for restoring and conserving the soils of specific regions.

Ultimately, this research may help us answer various questions, including whether or not we can use a survey of plant and mycorrhizal fungi (along with soil type, climate, and management) to predict soil aggregation. Ecosytem restoration efforts may also benefit if we are able to produce “tailor-made mycorrhizal fungi inocula and seed mixes” in order to “enhance soil aggregation.” Better understanding of these traits could also be applied to sustainable agriculture in areas such as crop breeding and cover crop selection. This research is in the hypothesis phase right now, and “only controlled experiments employing a range of plant and fungal species” can reveal the role that certain plant root and mycorrhizal fungal traits play in soil aggregation as well as the full range of applications that this information might have.

Speaking of soil, did you know that the 68th United Nations General Assembly declared 2015 the International Year of Soils? The purpose of this declaration is to “increase awareness and understanding of the importance of soil for food security and essential ecosystem functions.” You can read a list of “specific objectives” on their About page.

Year of Pollination: Hellstrip Pollinator Garden

This month I have been reading and reviewing Evelyn Hadden’s book, Hellstrip Gardening, and I have arrived at the fourth and final section, “Curbside-Worthy Plants.” As the title suggests, this section is a list of plants that Hadden has deemed worthy of appearing in a curbside garden. It’s not exhaustive, of course, but with over 100 plants, it’s a great start. Photos and short descriptions accompany each plant name, and the plants are organized into four groups: showy flowers, showy foliage, culinary and medicinal use, and four-season structure.

This list is useful and fun to read through, but there isn’t much more to say about it beyond that. So I have decided to write this month’s Year of Pollination post about creating a hellstrip pollinator garden using some of the plants on Hadden’s list. Last year around this time I wrote about planting for pollinators where I listed some basic tips for creating a pollinator garden in your yard. It’s a fairly simple endeavor – choose a sunny location, plant a variety of flowering plants that bloom throughout the season, and provide nesting sites and a water source. If this sounds like something you would like to do with your hellstrip, consider planting some of the following plants.

Spring Flowers

Spring flowering plants are an important food source for pollinators as they emerge from hibernation and prepare to reproduce. There are several spring flowering trees and shrubs on Hadden’s list. Here are three of them:

  • Amelanchier laevis (Allegheny serviceberry) – A multi-trunked tree or large shrub that flowers early in the spring. Other small trees or shrubs in the genus Amelanchier may also be suitable.
  • Cercis canadensis (eastern redbud) – A small tree that is covered in tiny, vibrant, purple-pink flowers in early spring.
  • Ribes odoratum (clove currant) – A medium sized shrub that flowers in late spring. Try other species of Ribes as well, including one of my favorites, Ribes cereum (wax currant).

There aren’t many spring flowering herbaceous plants on Hadden’s list, but two that stood out to me are Amsonia hubrichtii (bluestar) and Polemonium reptans (creeping Jacob’s ladder).

Creeping Jacob's ladder (Polemonium reptens) is native to eastern North America and attracts native bees with its mid-spring flowers. (photo credit: www.eol.org)

Creeping Jacob’s ladder (Polemonium reptens) is native to eastern North America and attracts native bees with its mid-spring flowers. (photo credit: www.eol.org)

Summer Flowers

There is no shortage of summer flowering plants, and Hadden’s list reflects that. When planting a pollinator garden, be sure to include flowers of different shapes, sizes, and colors in order to attract the greatest diversity of pollinators. Here are a few of my favorite summer flowering plants from Hadden’s list:

  • Amorpha canescens (leadplant) – A “good bee plant” and also a nitrogen fixer.
  • Asclepias tuberosa (butterfly weed) – “Valuable pollinator plant and larval host for monarch, gray hairstreak, and queen butterflies.” I love the tight clusters of deep orange flowers on this plant.
  • Coreopsis verticillata (threadleaf coreopsis) – I really like coreopsis (also known as tickseed). Try other species in the genus as well.
  • Penstemon pinifolius (pineleaf penstemon) – North America is bursting with penstemon species, especially the western states. All are great pollinator plants. Pineleaf penstemon is widely available and great for attracting hummingbirds.
  • Salvia pachyphylla (Mojave sage) – A very drought-tolerant plant with beautiful pink to purple to blue inflorescences. Salvia is another genus with lots of species to choose from.
  • Scutellaria suffratescens  (cherry skullcap) – A good ground cover plant with red-pink flowers that occur from late spring into the fall.
The flowers of butterfly weed (Asclepias tuberosa). Milkweed species (Asclepias spp.) are essential to monarch butterflies as they are the sole host plant of their larvae.

The flowers of butterfly weed (Asclepias tuberosa). Milkweed species (Asclepias spp.) are essential to the survival of monarch butterflies as they are the sole host plant of their larvae.

Fall Flowers

Fall flowering plants are essential to pollinators as they prepare to migrate and/or hibernate. Many of the plants on Hadden’s list start flowering in the summer and continue into the fall. A few are late summer/fall bloomers. Here are some of my favorites:

  • Epilobium canum (California fuchsia) – “Profuse orange-red tubular flowers late summer into fall furnish late-season nectar, fueling hummingbird migration.”
  • Liatris punctata (dotted blazing star) – Drought-tolerant plant with tall spikes of purple-pink flowers. “Nectar fuels migrating monarchs.”
  • Symphyotrichum oblongifolium (aromatic aster) – Loaded with lavender-blue flowers in the fall. It’s a spreading plant, so prune it back to keep it in check. Hadden recommends it for sloped beds.
  • Agastache rupestris (sunset hyssop) – Spikes of “small tubular flowers in sunset hues attract hummingbirds, butterflies, and bees midsummer to fall.” Try other species in the Agastache genus as well.
  • Monarda fistulosa (wild bergamot) – The unique flower heads are like magnets to a wide variety of pollinators. Also consider other Monarda species.
Lemon beebalm (Monarda citriodora), an annual plant that attracts an array of pollinators.

Lemon beebalm (Monarda citriodora), an annual plant that attracts an array of pollinators.

As with any other garden, your hardiness zone, soil conditions, water availability, and other environmental factors must be considered when selecting plants for your hellstrip pollinator garden. Groups like Pollinator Partnership and The Xerces Society have guides that will help you select pollinator friendly plants that are suitable for your region. Additionally, two plans for “boulevard pollinator gardens” complete with plant lists are included in the book Pollinators of Native Plants by Heather Holm – one plan is for sunny and dry spots and the other is for shady and wet spots (pgs. 268-269). Once your pollinator garden is complete, consider getting it certified as a pollinator friendly habitat. There are various organizations that do this, such as the Environmental Education Alliance of Georgia. If you are interested in such a thing, the public nature of your hellstrip garden makes it an ideal place to install a sign (like the one sold in The Xerces Society store) announcing your pollinator garden and educating passersby about the importance of pollinator conservation.

habsign

Other “Year of Pollination” Posts

Book Review: Hellstrip Gardening, part three

The second section of Evelyn J. Hadden’s book, Hellstrip Gardening, is all about the unique challenges and obstacles one faces when gardening in that stretch of land between the sidewalk and the road. I highlighted some of those challenges last week. This week we are into the third section of Hadden’s book, the part that is all about designing, building, and managing a curbside garden. As I have read through this book, I have begun to look at hellstrips in a much different light. They are no longer boring sections of yard with little potential, but instead are full of possibility and have unique characteristics involving publicity and functionality that are absent from most of the rest of the urban landscape. Now that we are in the creation phase of the book, this fact becomes abundantly clear.

Choosing a Style

When deciding how to design and plant your curbside bed, it is important to consider – along with aesthetics – the functions you wish to achieve (storm water runoff collection, food production, wildlife habitat, etc.) as well as how you are going to maintain it. You may decide to embrace minimal maintenance with a mass planting of a single species or mass plantings of a handful of species in sections called drifts. This can be very attractively done, but it also has the risk of a disease or pest wiping out a section of plants. A mass planting of ground covers acts as a living mulch and will eliminate the need to replenish non-living mulch. Hadden provides descriptions of a few styles of garden design, such as formal, naturalistic, cottage garden, and stroll garden, each with their virtues and limitations. Growing food is also an option in a hellstrip. If this is the option you choose, keep the bed looking full by intermixing flowers and crop plants, growing perennial crops, and staggering planting times. Ultimately the style of the garden is the preference of the gardener; however, the environmental conditions of the hellstrip must also be a consideration.

Choosing Plants

Because hellstrips are by nature public gardens, they are the ideal place for plants that appeal to the human senses – plants that invite interaction. Hadden calls these plants “friendly plants.” They are plants that are aromatic, have interesting textures and bold colors, “feel great underfoot,” have “aesthetically pleasing symmetry,” and have unusual flowers or unique foliage. Hadden asserts that, “plants that invite touching engender good will,” so consider the ways that your hellstrip might make you a better neighbor.

Their public nature also means that hellstrip gardens are not the place for rare and valuable plants, and instead are ideal for easily replaceable and self-repairing plants. This includes perennials that are easily divided, shrubs that reproduce by layering, creeping plants that send out runners, and plants with seeds that are easily collected and can be sown in bare spots. One option is to plant only annuals. This eliminates the loss of plants during the winter when snow, sand, and/or salt are deposited in the beds by road clearing equipment. Just be sure to protect the soil with mulch or a cover crop during the cold months of the year.

A hellstrip is also an ideal location for an alternative lawn. Traditional lawns require loads of water and fertilizer and regular mowing in order to stay looking good. There are lots of other grasses and ground covers available now that are drought tolerant, require little or no fertilizer, don’t need to be mowed often or at all, and are still very attractive. Hadden has a website all about lawn alternatives called Less Lawn.

The seed heads of blue grama (Bouteloua gracilis), one of many attractive alternatives to traditional turfgrass. (photo credit: www.eol.org)

The seed heads of blue grama grass (Bouteloua gracilis), one of many attractive alternatives to traditional turfgrass. (photo credit: www.eol.org)

When selecting plants for your hellstrip garden, consider the conditions it will have to endure. Unless you want to make serious amendments in order to accommodate certain plants, it is probably best to choose plants that are already adapted to your site. One way to determine this is to observe sites similar to yours and see what is thriving there; particularly make note of plants that look like they have been there for a while. Also, feel free to ask local experts at garden centers and public gardens what they might recommend for your site.

Earthshaping

“Diverse topography makes a more visually interesting garden, and it adds microclimates, letting you grow more diverse plants.” Shaping a curbside bed can also serve other functions such as softening traffic noise, defining pathways, collecting runoff, and providing wildlife habitat. When building a large berm, first create a rocky base and then fill in the spaces between the rocks with sand and small gravel. After that, add topsoil and firmly pack it down with machinery or a rolling drum. Small berms can be formed by simply piling up excess soil or turning over sections of sod and piling them up. Maintain good plant coverage on berms in order to reduce erosion, and consider planting shrubs with extensive root systems like sumac (Rhus sp.) and snowberry (Symphoricarpos sp.).

Hellstrips are ideal locations for rain gardens and bioswales since they are typically surrounded by impervious surfaces. Storm water can be directed from these surfaces into your rain garden, thereby reducing the amount of storm water runoff that must be handled elsewhere. Hadden provides a brief overview on how to construct a rain garden; the process is too detailed to go into here. If you are serious about building one, it is important to do your research beforehand to be sure that it is built properly. There are several great resources available; one that I would recommend is Washington State University Extension.

Partnering with Nature

Time spent managing and maintaining your hellstrip garden can be greatly reduced when it is well planned out, contains plants that are suited to the site, and has good soil health. Helping you achieve these things is essentially what Hadden’s book is all about. Watering properly and wisely is key to the success of your hellstrip garden. Hadden suggests organizing plants into “irrigation zones,” separating those that need little or no water from those that need frequent or regular watering. When you do water, water “thoroughly and infrequently to maximize deep root growth and drought resistance.” Consider installing a drip irrigation system, particularly one that will direct the water to the roots of the plants and deliver it slowly. Avoid watering areas where there are no plants, as this encourages weed growth.

Mostly likely you will be doing some amount of trimming and pruning in your hellstrip. Consider how you will handle this plant material. You may choose to cut it up into fine pieces and leave it as mulch; or maybe you have a compost pile to add to. Large woody materials can be placed in a section of your property set aside for wildlife habitat. Choosing plants that will not outgrow the space will reduce the amount of pruning you will need to do.

As much as Hadden is an advocate for alternatives to conventional lawns, she is also an advocate for reducing the use of gas-powered leaf blowers. Nobody enjoys hearing the clamor of a smelly, polluting leaf blower echoing through the neighborhood, so be a good neighbor and use a broom or rake instead. You will probably enjoy the task more as you listen to nature, get some exercise, and revel in your garden.

Continued focus on building healthy soil is paramount to the ongoing success of your curbside garden. Continue to add organic matter by letting some of the plant litter lie and decompose. Plant nitrogen fixing species like lupines (Lupinus sp.) and false indigos (Baptisia sp.). As much as possible avoid compacting the soil, especially when it is wet, and keep tilling and digging to a minimum once the garden is planted.

Partidge pea (Chamaecrista fasciculate), an annual plant in the pea family (Fabaceae). One of many nitrogen fixing plants that can help improve soil health. (photo credit: www.eol.org)

Partridge pea (Chamaecrista fasciculata), an annual plant in the pea family (Fabaceae). One of many nitrogen fixing plants that can help improve soil fertility. (photo credit: www.eol.org)

Again, this is only a fraction of what Hadden discusses in this section of her book. Consult the book for more of her wisdom. The final section of Hellstrip Gardening is a long list of plants that are “curbside-worthy” complete with photos and descriptions. Next week’s post will be all about a particular type of hellstrip garden that employs a subsection of those plants.