What are “Natives” and why are they important?

Plants are considered “native” if they occur naturally in the place where they evolved. Native plants are those plants that evolved as part of the overall ecosystem. They often:

• are habitat for native animals
• sustain other life such as forage or shelter for animals
• have deep root systems that hold soil and decrease erosion
• have root systems that absorb excess standing water decreasing surface water runoff
• are tolerant of area temperature and moisture fluctuations requiring minimal care
• can solve other problems such as air pollution and heat (trees), excessive wet areas (rain gardens), excessive dry areas (erosion control) and so much more by planting the right plant in the right place

What to consider when matching a plant and a place

• Light
• Temperature
• Soil
• Water
• Aggressiveness

Light

It is easy to say a plant needs light but the question is how much light. Some plants prefer shady areas such as forest (nothing grows under trees) or woodlands (plants will grow under trees) or the shady side of a structure while others require full sun such as on prairies (land with usually deep fertile soil, a cover of tall coarse grasses, and few trees), glades (open space in a forest), savannas (land containing scattered trees and drought-resistant undergrowth) and the sunny side of a structure. For example, our mural wall actually faces north but gets full sun (defined as more than 6 hours of sunlight per day). Consequently, we installed plants that thrive in full sun: daffodils, amsonia, coneflowers, New England asters. All of these plants are native to Missouri and, once established, will need minimal care.

Some plants, such as most vegetables, require more than 6 hours of sunlight to mature. Tomatoes in particular need 8-10 hours of sun per day to thrive and bear fruit. Other plants prefer only partial sun (3-5 hours) such as some azaleas, periwinkle and bluebells while others require full shade such as some ferns, columbine, ginger and mayapples. Azaleas are not native to St. Louis and require care to feed and water while the native bluebells will spreas with abandon and prefer to be undisturbed.

Temperature

Different plants tolerate different temperature extremes. Some plants, such as tropicals, thrive in the south but can not tolerate our winters. Other plants tolerate our winters but can not handle our heat without assistance. USDA has created two maps to help identify what plants will thrive in what temperature ranges.

The classic example of heat hardiness is lawn grass. Some grasses, such as zoysia and bermuda, require the heat to grow but can not tolerate cold. Theses grasses tend to be dormant i.e. brown until the heat of summer. On the other hand, fescue and bluegrass are considered cool season grasses. The roots actually grow in the fall and the blades green up as soon as the ground temperatue is above 50 degrees. However, they are generally stressed in our heat, hence they tend to turn brown in August but green back up in September when the temperatures decrease. Same principle holds for other plants, such as pansies, as well.

Soil

Composition

As discussed in the section of soils, “dirt” is made up of a mixture of sand, silt, clay and loam as well as a variety of micro-organisms and trace minerals. In general, the soil around the metro area is a clay loam. That is not necessarily true everywhere though. Soils that have been well amended with organic matter may have significantly more silt. If sand has been mixed into the soil to address drainage, the standard proportions of a clay loam soil with be altered.

While there’s no such thing as a perfect soil, different plants grow best in different types of soil. Most common garden plants prefer loam — soils with a balance of different-sized mineral particles (approximately 40% sand, 40% silt, and 20% clay) with ample organic matter and pore space. However, some plants grow better in sandy soils, while others are well-adapted to clay soils.

To test your soil:

1. Fill a clear container with straight sides about two-thirds full of water; then add enough soil to nearly fill the jar. You can also add a pinch of laundry detergent to help the soil components separate well. Shake the jar vigorously and then set it in a place where it won’t be disturbed.
2. Observe the jar over the next couple of days as the particles settle into layers. The larger sand particles are heaviest and settle at the bottom, followed by a layer of silt, then topped by a layer of clay. The clay may stay suspended and cloud the water for several days, which is why the sample needs to sit undisturbed. Organic matter will float on or just below the water surface.
3. Measure the height of each layer, as well as the overall height of the soil (including all layers). Then translate these measurements into percentages for each component by dividing the height of each component by height of the sample.

Use the U.S.D.A Natural Resources Conservation Service’s Soil Textural Triangle to determine the soil type by drawing lines to represent the percentages of the three components. The point where they converge is the soil texture; in this case, between a sandy loam and a sandy clay loam.

By adjusting the per-centages of the components, the soil can be improved to meet the needs to the plants. (Note: be careful if you want to add sand. Sand and clay make brick, not good soil for plants. Compost and well rotted manure will break up soil for better drainage much better than sand!)

Acidity

One of the most overlooked aspects of soil is its acidity/alkalinity. The acidity of a soil determines which nutrients are available to the plants. More acid soils allow different microbes and nutrients to be available to a plant which differs from more alkaline soils. Soils west of the Mississippi tend to have more alkaline soils (Soils above 7 on the pH scale). The pH scale is the measure of the potential Hydrogen available. Below is a pH scale for common foods.

Plants need food (nutrients) too and the pH affects the nutrients available in the soil as seen in the chart below with strongly acid to the left and strongly alkaline to the right.

Testing your soil’s pH will give you a good idea of what the soil needs for the plants you want to grow. For example, in my front yard, I grow azaleas, magnolia, spruce and ivy. They face north and have the correct amount of sunlight. However, all of these plants require a more acidic soil (around 6-6.5) then my yard’s average of 7.1. Consequently I had to acidify just that part of the yard. This can be done by adding sulfur (not recommended) or gradually adjusting the pH by adding coffee grounds, diluted whey (the greenish white liquid formed when milk sours or at the top of sour cream) or acidic compost and mulch. On the deck area, pots of blueberries (prefer pH of 5.5) and raspberries (prefer pH of 6) grow. They receive more dilute whey or coffee grounds than the front yard as they require a more acidic environment to thrive. On the other hand, in the back yard, I have roses (prefer acidic) and lavendar (prefers alkaline) along with many other plants more comfortable in a neutral soil. First, the roses and lavendar can not grow in the same area as their needs are different. Second, each gets different care with roses getting dilute whey each spring and lavendar getting a neutral to alkaline feed.

Something not growing where you think it should? You can take soil samples in to the University of Missouri Extension office for testing, buy an expensive gadget or you can test yourself. Test the soil pH yourself:

• Take a small handful of soil and rub your hands with it. This will clean off anything on your hands that might affect the soil.
• Take another clean handful of soil. Wet the soil with vinegar. If it fizzes and bubbles you have alkaline soil.
• Take another clean handful of soil. Add baking powder and then wet the soil baking powder mix with distilled water. If it fizzes your soil is acidic.

To use the test strips (available at any pool supply or aquarium place, just be sure they have a range of at least 4.4-8):

• Rub your hands with a small handful of soil to clean off anything on your hands that might affect the soil.
• Take a small handful of soil and wet it thoroughly with distilled water. You could also use a plastic lid to mix the soil with distilled water.
• Touch the test strip to the water and soil mixture and wait for the color to change.
• Compare the color to the color chart that comes with strips. Take the reading from the area that is closer to the soil rather than further away where the water wicks up to.

Water

Water, water, everywhere but not a drop to drink! Plants need water but the quality and quantity of the water will determine what lives and what does not. As with soil, some water is slightly more acidic or alkaline then other water. East coast soil is slightly more acidic than west of the Mississippi as water filters through that soil. Our water tends to be slightly alkaline in many places as it has picked up lime particles as it filtered through the soil. Additives and processing of water can affect not only taste but acidity. There is little that needs to be done with the water unless you are trying to significantly alter the soil pH or the water is polluted.

Quantity, on the other hand, is an issue to be considered. Some plants require water all of the time (rain forest) while others prefer a good drenching once or twice a year (desert). Note that none of those plants survive in the Midwest with our wet springs and dry late summers.

An assessment of the water drainage of an area will determine any adjustments needed and which plants will grow there. Things to consider include:

• slope of the ground
• high and low spots
• overhangs and roofs that spill additional water into an area
• water quality and potential pollutants
• how long does the water stand or does it evaporate and absorb immediately
• is water runoff affecting adjacent property
• is water causing flooding, mosquitos or sewer back ups

The engineers from Engineers Without Borders are considering all of these factors when designing the parks. These factors went into the design of the native garden in front of the mural wall:

• the ground slopes north from the wall to the asphalt
• high and low spots were evened out with the additions of the soil preventing standing water in the garden
• water will be coming from the city hydrants (city processed water) until the garden is established. Water will be coming from rain after the garden is established.
• There are no overhangs, roofs or extensive tree canopies but there will be sheeting from the water hitting the retaining wall as well as water runoff every 10-12 feet at the drains for the wall.
• Water runs to the asphalt and runoff, if much, will be addressed when drains are installed for the Greenway

Essentially, once established, the native garden will have full sun, clay loam soil ammended with compost and water consistent with this area to support plants “native” to or consistent with our ecosystem. These plants will not only grow (and thrive) where they are planted but also provide food and shelter to native birds and butterflies while creating a restful area in the middle of the city.

What is an “Invasive” plant

“Invasive” plants can be native or non-native plants which are aggressive in their growth, usually crowding out or killing other plants around them. Non-native invasive plants are particularly troublesome as they do not provide shelter or forage for native animals, do not generallly control erosion or water runoff, and kill off the native plants that do provide these benefits. The classic example in the city is Bush Honeysuckle.

Bush honeysuckles are large, upright, spreading shrubs reaching up to 15–20 feet in height, with flowers that change from white to yellow; juicy red berries; and opposite, simple leaves that green up much earlier than surrounding native vegetation. Leaves are deciduous, opposite, simple, 1–3 inches long, narrowly oval with a rounded or pointed tip, the margin entire (not toothed or lobed); upper surface green, lower surface pale green and slightly fuzzy. In late autumn, leaves typically remain green and attached well after the leaves of our native trees and shrubs have fallen. These are the weedy looking trees that have grown up in alleys and along fence rows as well as along our native trees in vacant lots.

This had to be removed both by cutting and spraying and will have to be sprayed out for several years to keep it from coming back into the native garden along the Mural Wall and the Lewis Place Park.