So I knew when developing the plant palette for the Sands House in historic Annapolis that I would need to adjust my approach. The yard is urban and tiny. The planting spaces were dry and temperatures were exacerbated by the heat that reflected off adjacent buildings. With little room for trees and the only shade being provided by buildings, the planting spaces quickly changed from full shade to full sun throughout the day as the sun moved across the site. 

Everything that was planted there needed to be an appropriate scale and remain tidy throughout most of the growing season. When referencing plant community analogues to develop the heavily native palette, Poverty Oats (Danthonia spicata) popped up in the list. Danthonia spicata prospers in full sun or part sun and infertile dry sandy or rocky soil and tolerates drought. Given the urban soil that we had to work with, which was dusty in texture and had already yielded a truck load of broken red brick, glass, oyster shells and animal bones, it seemed to fit the bill, so I included it in the palette.

Two growing seasons later and the Poverty Oats has filled in remarkably well and looks surprisingly tidy and ornamental. It has the same scale and effect as the exotic Fountain Grass (Pennisetum alopecuroides) and seems just as durable. For a small grass that is barely noticeable in its native habitat it can hold it’s own in a small garden.

Rhexia mariana is one of those plants that I discovered when developing a project plant list from a natural plant community analog. I would have otherwise never have considered it. Three years later, it has filled in quite nicely in the lower parts of the SPSC that I built where there is a minimum amount of consistent moisture. It provides solid ground coverage, filling in the ground plane around taller plants, and withstands the occasional high flow event. Grows one foot tall with pinkish-white flowers from June through October and prefers full sun.

From Plant Delights Nursery, this is probably my all time favorite plant description:

“…can be found in roadside ditches, pond edges, and wet prairies…a habitat also preferred by crushed beer cans and used condoms.”

For some inexplicable reason, they had the idea to run all of the proposed construction traffic through the neighboring Hillsmere community, rather than access the site from their own park, so it was quickly shot down. Prior to development, there was a farm road that ran straight from Forest Hill Dr in Hillsmere to Quiet Waters Park Rd, complete with a hedgerow that still stands today. So it wouldn’t have been a stretch to implement construction access from that direction. Anyhoo, the dog doesn’t care about any of that…

The top of the site is flat and open, with an amazing, $3.9m view of the South River and the Chesapeake Bay beyond. Sorry, rich people, better luck next time. The dog is grateful. It is a low grassy meadow, with surprisingly little turf grass mixed in, save for Red Fescue. We spotted several native forbs poking out of the meadow, which was relatively dry and sun/part-sun in most locations.

Salvia lyrata, Lyreleaf Sage, above. Hypoxis hirsuta, Yellow Star Grass, below.

Hieracium venosum, Rattlesnake Weed, above. In addition, we found broad stands of Gaylussacia baccata, Black Huckleberry, in drier, light-shade woods. We also found a couple of specimens of Rush (actually Luzula) that I have never seen before. Luzula echinata, Hedgehog Wood Rush, found above the toe of a slope.

Also, in case anyone was wondering, we don’t do outdoor kitchens.

You can read the full description of our project in our previous post:

https://welspryng.llc/welspryng-selected-as-a-finalist-in-the-2021-bubbas/

But wait, there’s more! Voting is open to the public through May 24th to select the Best Overall out of the seven category winners. There is no shortage of resources and talent amongst the other finalists. Can a small company using little more than a laptop, a mini-excavator and some unconventional ideas hold its own against the likes of Biohabitats, Environmental Quality Resources, Perkins & Will, the University of Virginia, and the U.S. Air Force? You decide! See link below for a list of the finalists and to submit your vote.

The Vernal Pool (A Different Approach to “Fixing” Drainage) was chosen by jurors as one of the 3 best projects in the Residential category. The category recognizes exceptional stormwater practices installed on a residential property. The project description follows below.

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Welspryng was retained by the homeowner in the Spring of 2019 to address drainage issues on their property. The homeowner’s lawn service was making a mess of large wet areas of turf in the backyard. A flat area held surface water, implying a grading problem, but test pits showed groundwater nearly at the surface, indicating a seasonally high water table. The homeowner was fully onboard with getting rid of some lawn and creating habitat, but with the site being so wet in the spring and then drying out in the summer, it would be challenging to implement a typical rain garden plant palette.

The proposed solution: Make it wetter.

Vernal pools are small, shallow, ephemeral water bodies. They fill each spring by rain and snow melt and are drier for a period of time during the summer. They support several species of animals that require these temporary wetland habitats. Approaching the drainage “problem” as an opportunity, additional runoff was directed towards the project area. The goal was to increase the hydro-period (i.e., the timing and duration of inundation) to extend the seasonal surface ponding and increase the sub-surface moisture level during the drier months. This permitted the use of a wetter community of plants that could better tolerate the seasonal ponding and fluctuations in water level, in essence creating a vernal pool.

To that end, three downspouts (975 square feet of roof area representing 20% of site impervious) were piped from the house to an 18-inch catch basin modified to filter out fine and coarse debris. The initial flush passes through the filter then enters a series of sub-surface detention chambers (480 gallons), placed adjacent to the ponding area and embedded in pea gravel. Runoff that is detained in the perforated chambers slowly percolates into the sub-grade under the ponding area through a sand-filled trench to supplement soil moisture and irrigate plants from the bottom up during drier periods. The project functions similar to a submerged gravel wetland in this respect, with the chambers providing the detention volume that is normally created by the voids in the gravel. The advantage of this innovative approach is that it eliminates the need to excavate and dispose of a large volume of soil and replace it with tons of imported gravel during construction.

When the chambers are full, gravity forces excess water up and out of the top of the catch basin to fill the ponding area. The basin functions like a conventional rain garden, with the ponding water infiltrating directly to the plant roots. An overflow at the far end filters water through a vegetated swale along the rear property line before reaching a county storm drain inlet in a nearby yard.

A unique approach to planting

Two dumpsters of sod were removed and 1,500 square feet of the back yard were planted with a native plant community based palette. Using data from USDA, Maryland DNR, NatureServe, the U.S. National Vegetation Classification (USNVC), VegBank and the Maryland Plant Atlas, Welspryng has developed a reference database for generating plant palettes based on natural plant community analogs that are likely to occur in Anne Arundel County. Most accepted definitions of a plant community include four central ideas: 1) uniform physical structure, 2) uniform habitat, 3) shared floristic composition, and 4) recurring distribution across a landscape. An advantage of this approach is that it can produce plant species palettes that are intrinsically tailored to the anticipated site conditions.

The USNVC is a standard process for identifying and cataloging plant communities. In this case, a list of species found in plots from CEGL006499 – Coastal Plain / Outer Piedmont Seepage Bog was cross-referenced with plant records for Anne Arundel County from the Maryland Plant Atlas to create a reference palette that informed plant species selections. This method is distinctly different from the conventional practice of assembling palettes per the subjective preferences of the designers, which commonly result in arbitrary collections of native plant species.

Many popular natives were present in the reference palette, such as Magnolia virginiana, Clethra alnifolia, Aster novi-belgii, Solidago rugosa, Juncus effusus and Carex crinita. However there were also many less commonly used natives in the reference palette which are commercially available but otherwise may not have been considered, such as Vaccinium corymbosum, Solidago fistulosa, Rhexia virginica, Ludwigia alternifolia, Triadenum virginicum, Woodwardia areolata, Dichanthelium clandestinum, Panicum anceps, Juncus canadensis and Eleocharis obtusa. The palette that resulted from this unique process features a more diverse selection of plants that looks more like a native habitat that may be found locally.

Lastly, it can’t go without saying that having the full support of the client made a huge difference in the success of this project. A simple drainage project was reimagined to also detain/retain impervious runoff, express the beauty of a native plant community and establish habitat. During the first growing season there were monarch butterflies, a ton of dragonflies and tadpoles, believed to be wood frogs, were observed in the vernal pool. What would perhaps have otherwise been addressed with a conventional, one-dimensional drainage solution by some has instead been allowed to fulfill its potential as an extraordinary stewardship opportunity.

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Presented by the Chesapeake Stormwater Network, the virtual awards ceremony for the 5^th edition of the Best Urban BMP in the Bay Awards will be held on March 10^th from 3-5pm. The 1^st place winner in each category will be announced during the 10^th edition of the Bay-wide Stormwater Retreat and the ceremony will officially kick off the “people’s choice” internet voting to determine who will take home the title of the overall BUBBA.

I have been involved in some aspect of the landscape industry my entire adult life. Along the way, I have encountered an endless world of plant species to discover and learn about. At this point in my career I have probably forgotten more than I have learned, yet I still have only forgotten a fraction of what there is yet to know. One of my latest discoveries, by happy accident, is Carex lurida.

The common name for Carex lurida is Sallow Sedge, or, maybe it’s Shallow Sedge. I suspect one of these is a misspelling but haven’t been able to determine which. The MD Biodiversity Project, MOBOT and the U.S. FWS Native Plant Guide refer to it as ‘Sallow Sedge’. The USDA, North Creek and Pinelands Nurseries refer to it as ‘Shallow Sedge’. The LBJ Wildflower Center references both names and others only refer to it as ‘Lurid Sedge’. As it turns out, ‘Sallow’ is actually a word – not a typo, meaning “of a sickly, yellowish or lightish brown color”. Lurid also turns out to be an actual word, meaning “sallow, ghostly”. The sedge does have a yellow-green color, but I wouldn’t go so far as to describe it as “sickly”. Nor, I suppose, would I describe my vocabulary as extensive, after this latest humbling excursion into the dictionary.

Carex lurida is listed as a wetland obligate in the Atlantic and Gulf Coastal Plain region. It is found in swales, seeps, wet meadows and fields, and on the margins of marshes and can tolerate periodic inundation. The foliage, as previously mentioned, is a yellow-green, which does not necessarily distinguish it from other wet sedges. It is clump forming, growing 18 to 30 inches. The most distinguishing feature are the seed heads, appearing in May-June, which are approximately 1-1/2 inches long and have a bristly feel and appearance.

I noticed this sedge at the rear of a neighboring property when I was doing reconnaissance for a stormwater project. I took a piece home and identified it as the native Carex lurida and decided that it would work well in my project. I subsequently ran into the owner of the property, who was renovating the house as a flip, and asked if I could grab a few clumps to transplant into my project. He was more than happy to oblige, as the sedge was starting to break through the rear fence and bully the lawn turf.

What impressed me most was the resilience of this plant. The house was listed for sale last July, just at the start of an unseasonably dry summer. Rather than take the chance that the future owners may feel differently about sharing plants, I quickly leapt into action and transplanted two dozen clumps into my recently completed drainage project. After a brief shock, the plants recovered remarkably well and established themselves quickly, even during the drought. Carex lurida is comparable in height and habitat to Juncus effusus and appears to be more robust and drought tolerant. I would consider this a ‘must-include’ for any raingarden or bioretention project.

Although most plants have yet to show any signs of life, it is not far off. Now is the best time to clean out planting beds because it is easier to do so before plant growth starts. The dead foliage from last season’s herbaceous plants should be clipped and excessive leaf litter should be raked from the beds.

Plants are integral to the performance of a BMP. Plants take up nutrients as they grow, the root systems stabilize the soil and the stems slow down the velocity of runoff passing through the BMP. It is critical to have a maintenance provider that can distinguish between which plants should be growing in the BMP facility and which should be considered weeds.

Most landscape maintenance companies (a.k.a. Mow and Blow) do not possess the plant knowledge and experience necessary to adequately maintain native plantings and BMPs. The average maintenance crew that descends upon a BMP like locusts wielding weed eaters and leaf blowers risks damaging desirable plants and leaving invasive plants in place. Just as competent physicians are necessary to provide sufficient health services, so too are competent service providers necessary for maintaining the health of a stormwater BMP investment.

There may come a time when you need a stormwater or drainage solution that requires sub-surface drainage i.e. pipes. Two kinds of pipe are commonly used in small scale drainage projects. Corrugated plastic pipe and rigid PVC pipe are comparable in material cost but differ significantly in installation cost and reliability.

Corrugated plastic pipe is available at any home improvement store. The ease of handling and installation has made it a favorite for the average landscaper. It is so ubiquitous that its use goes unquestioned, having achieved the status of ‘conventional wisdom’.

The advantage of corrugated plastic pipe (for the installer) is that it is flexible.

• The flexibility allows the pipe to be packaged and sold in long coils, making it economical to handle and ship.
• The continuous length requires fewer couplings and thus less labor to install.
• Less care and skill are required to excavate trenches when compared to rigid pipe, which requires trenches in straight lines with turns at specific angles to match elbow joints in the pipe run, thus less, and/or cheaper, labor is required to install it.

The disadvantage of corrugated plastic pipe (for the owner) is that it is flexible.

• The hose-like flexibility makes it difficult to lay the pipe flat along a trench to achieve a continuous slope. The resulting undulations in the profile create low spots along the pipe run.
• The corrugations that afford flexibility also function as speed bumps, reducing the velocity of the water flow and its corresponding capacity to flush sediment and debris out of the pipe.
• The cumulative effect is that sediment and debris will readily settle in the pipe, reducing its capacity over time.
• There is no way to clean out corrugated plastic drain pipe. The drain snake that is commonly used by plumbing services features a whirling blade that will readily tear through the soft plastic walls of the pipe.

If I had a dime for every linear foot of crushed, muck filled, corrugated plastic pipe I pulled out of the ground… OK, so it’s an old cliché. The ‘dime’ part is also dated, since it costs allot more than that, given the cost of the original installation, the replacement cost after it fails and the cost of the subsequent damage that may be encountered because of a failed drainage system.

Rigid PVC Sewer and Drain Pipe (SDR) on the other hand, while requiring more planning and time to install, can provide many more years of reliable service. Not to be confused with DWV (Drain, Waste and Vent) or Schedule 40 PVC, Sewer and Drain pipe has a thinner wall and thus requires different sized fittings (a tip for those DIYers). Because it is rigid, it is easier to ensure an accurate and continuous slope during installation. The smooth pipe walls have less friction loss than corrugated pipe. The resulting higher flow velocity facilitates self-cleaning and efficiently transports sediment and debris out of the pipe. Finally, if there ever is a need to clear the pipe, it can be snaked using conventional equipment.

Cost wise, the two products are comparable. However, rigid PVC must be cut and fitted with an elbow using PVC cement at each turn in the pipe run. Elbows are available in 22.5, 45 and 90 degree angles, so advance planning and layout are required to ensure that the required fittings are in hand and that the layout will fit around existing site features. It requires more time and effort to install rigid PVC, which is reflected in the project cost.

When comparing bids from installers, the bid that proposes rigid PVC pipe will most likely be higher than a bid proposing corrugated plastic pipe. However, the savings that are realized from choosing the corrugated plastic pipe may be outweighed by the shorter service life of the installation and a higher life-cycle cost. Life-cycle cost is calculated by taking the initial cost, adding anticipated maintenance costs, and dividing it by the number of years before the installation must be replaced. For example, a product that initially costs $3000, requires $100 in maintenance every other year, and lasts 10 years has a life-cycle cost of $350/year. A product that initially costs $4000, requires $100 in maintenance every other year, and lasts 20 years has a life-cycle cost of $250/year.

If a problem is significant enough to warrant the expense of installing a drainage system, then it is significant enough to invest in a solution that will remain reliable for as long as possible.