Plant indicators in field and garden
Illustrations are from the USDA Publication Selected Weeds of the United States, 1970
Mallow (Malva neglecta Wallr.) (M. rotundifolia L.)
Common names: round-leaved mallow, cheeses, low mallow
Indicator value: Mallow indicates a soil very rich in nitrogen, moisture fresh or intermediate and intermediate pH.
Habitat: Mallow grows on cultivated ground, pastures and new lawns.
Climate: warm, continental
Control: Hand weed or hoe when small, pull large plants and burn.
Fodder: Palatability varies with locality. Reports of fodder value vary from slight value, to cattle fond of it. Bees work mallow when there is little else to attract them, and it is of little value to the bees.
Food: The root, when cooked, yields a sweetish mucilage that is edible, and used for syrup, deserts, and lotions. The fruits are edible. Young leaves can be used in salads. The leaves are used to curdle milk to make cheese.
Use: food, herbal, skin lotion, poultice (2300)
Discussion: This common roadside plant has been used as a survival food and medicine like its cousin, marsh mallow, for millennia. Both the root and leaves have great value as a poultice for infected wounds. The mucilage from the cooked root can be used as egg whites to make chiffon deserts.
Storksbill (Erodium cicutarium L.)
Common Names: heronsbill, alfilaria, pin-weed,
Indicator value: Indefinite for nitrogen, indicator of dry soil, mostly on acid soil although indefinite as an indicator.
Habitat: on lawns and pastures
Climate: desert, between suboceanic and sub continental
Germination: Shallow cultivation of seed infested fields induces germination.
Control: hoe out rosettes as soon as recognized
Fodder: Storksbill is excellent spring forage, birds and wildlife eat the seeds, pollen and nectar for bees, nectar has highest tested sugar concentration. Great for spring stimulation of hives.
Use: pasture, fodder, nurse plant on hard saline soils
Discussion: Storksbill withstands concentrated alkaline salts, increases soil permeability, letting salts diffuse (5110).
Burr clover (Medicago hispida Gaertn.)
Indicator value: Indicator of low nitrogen and moist soil (4830) but tolerates drought (2705).
Soil description: The soil is moist, well drained, a fertile loam soil high in available nutrients (4830).
Control: Increase acidity and available nitrogen.
Fodder: The plant is not palatable at first, but livestock eat it freely after acquiring a taste for it (4830). Good for spring stimulation of bees (4700).
Use: pasture, green manure, best most economical cover crop (4830) great value to wildlife, especially quail, stock greedily eat pods, pods stick to sheep wool, hard to get out (2705).
Sow Thistle (Sonchus asper)
Common names: Prickly sow thistle, prickly lettuce.
Indicator value: Indicates a high nitrogen content. The weed also indicates the ground is very moist with a neutral pH.
Soil description: Good balanced loam
Control: Clean cultivate, then hand pull, hoe, or mow weeds waste places before seeds form. Use black plastic mulch to starve weeds.
Fodder: Sow thistle can be made into silage when green, and makes an excellent feed for geese and pigs. Bees obtain nectar from the flowers.
Food: Can be eaten in salads or as pot herb when young, gets bitter with age. Leaves can be blanched by covering with a can or bucket.
Use: food, forage
Willow herb (Epilobium hirsutum L.)
Common Name: willow-herb
Family: evening primrose
Indicator value: Willow herb indicates a soil rich in nitrogen, moist soil that doesn't dry out (1880) and a neutral pH (1880).
Soil description: The soil is gravelly, some what limey (4390) on low fields, especially along ditches.
Control: Improve drainage, and mow as first flowers appear.
Fodder: Willow herb is browsed by moose and deer. This is a valuable honey plant.
Chickweed (Stelaria media Cyril)
Common Names: starwort, starweed, bindweed, winter-weed, satin flower, tongue-grass
Indicator value: Indicates a very nitrogen rich soil with neutral to basic pH. If stunted, this plant indicates a low phosphorus level. Chickweed accumulates magnesium. The soil has a high concentration of organic matter on the surface and a moderate level of fermented organic matter.
Control: Clean cultivate when seedlings are small. In lawns mow close and rake.
Fodder: Pigs, poultry and birds are fond of buds and seeds.
Food: Chickweed is high in vitamin C and is great in salads. Lightly steamed, it is used as a bland flavored green. Blended with juices, it makes a refreshing green drink.
Use: food, fodder, ground cover.
Discussion: Chickweed makes most vigorous growth during cool weather when considerable moisture is available.
Nutgrass (Cyperus esculentus L.)
Common Names: yellow nut-grass, chufa, coco, coco sedge, rush nut, edible galingale, Earth almond
Family: sedge A ?
Indicator value: Indicates a wet soil, often not well aerated. The pH is on the acid side (1694).
Soil description: The soil is usually rich or sandy with poor drainage, especially low spots in fields (4390).
Control: Use 2 Chinese geese to the acre (train to dig tubers), improve drainage, and clean cultivate.
Food: The tubers have a nutty flavor and are delicious. Just dig them up, wash off the dirt, dry, eat and enjoy. The tubers are also good for flour to add "interest" to pancakes or blend to make a "nut milk." (2300)
Use: food, ornamental
Discussion: Nutgrass is an aggressive and invasive weed that is considered a problem on wet soils around the world. People around the world have used the tubers as food. The flowers, with their triangle symmetry, are a curiosity so find use in dried weed pots.
Charlock (Brassica kaber (DC.) L. C. Wheeler)
Common Names: wild mustard, field mustard, field kale, kedlock
Indicator value: Indicates low calcium if it has clubroot (5110), and low potassium if stunted (2910). The soil is neutral to basic pH (0460) with low humus (4810), and moderate to high fermented organic matter (2090). The surface is usually crusted or there is a plow pan (4810). Charlock accumulates phosphorus and salt (5110).
Soil description: Indicates area stressed by poor drainage, poor structure, that is sour, waterlogged, and where slime molds are growing (2090).
Habitat: spring grain fields, especially oats, cultivated land, waste places.
Germination: Frequent disking and wild oats stimulate the seeds to germinate (4390). Fusarium molds in soil stimulate mustards (2090).
Control: Clean cultivate then hand weed. Use mustard-free seeds. In wheat, harrow on a warm dry day when wheat is 4" high.
Allelopathy: Rape and beets inhibit charlocks growth (4810). Companion to fruit trees (5110).
Food: Leaves are good in early spring for salads and as a pot herb. The flavor is strong and spicy, so is usually mixed with milder greens (2300).
Use: food, orchard ground covers
Discussion: Charlock can be used to decrease salt in the soil, and sweeten acid soil (4810). It's extensive root system opens up heavy and compacted soils. Like other mustards it is a good winter ground cover in orchards that are disked in the spring.
Buckhorn plantain (Plantago lanceolata L.)
Common Names: English plantain, narrow-leaved plantain, rib-grass, rib-wort, black-jacks
Indicator value: Plantain grows on soils with a range of nitrogen, water and pH (1880). While the plant tolerates a low level of potassium, the potassium content of the leaves is proportional to the potassium in the soil (6220). A large area could be tested for potassium availability by just collecting plantain leaves and analyzing them. Usually the soil is moist and acid (1880). Plantain accumulates phosphorus and calcium (5110).
Soil description: Compacted, dense, possibly worked wet or trampled (4810).
Habitat: clover fields, meadows, lawns, paths, waste places
Control: Hoe out individual plants. If this is all that your lawn will grow, till it up, fertilize, add compost, and reseed (4390). In pastures and fields plant a clean cultivated crop for 2 years then reseed.
Germination: Plantain will germinate in complete darkness (0700) and can stand dense compacted soils (4810).
Allelopathy: Associates frequently with red clover (4810).
Fodder: Cattle like to eat plantain, which is high in protein. It is good for hay and has beneficial effects on cows (4810).
Food: The wilted leaves are used for cooling astringent compresses for bruises and strained joints. The seed oil (a high percentage of the seed) is fine and almost tasteless (4810).
Use: fodder, herbal
Discussion: Plantain is the most tolerant cool season weed to low potassium levels in the soil (2910).
Dandelion (Taraxacum officinale Webber)
Common Names: lions-tooth, blow-ball, cankerwort
Indicator value: This bright flowered weed indicates a nitrogen (1880) and phosphorus rich soil. If the plant is stunted this indicates a low phosphorus level (2910). The soil is usually rich in magnesium and potassium and low in calcium (2090) (3610). The concentration of potassium in the leaves is proportional to the potassium in the soil (6220). Soil moisture is fresh (1880), the pH is neutral to basic (0460), and the level of raw organic matter is moderately high (2090). The level of humus is low (2740).
Soil description: clay or heavy, good deep soil (2740)
Germination Sprouts the year after adding lime to an acid plot (3610)
Control: Spud out the roots. Cut off the tops before the seeds form and increase drainage and acidity.
Allelopathy: Dandelion is a good mother crop and companion to alfalfa (4810). The roots exude a substance that attracts earthworms (5110).
Fodder: Dandelion has a high protein content, makes good hay, has a protective effect for cows (5110) and makes a palatable nutritious feed for animals (5860).
Food: The leaves make excellent greens for salads or pot herb in the spring. The leaves get bitter with age but can be blanched by covering with large cans. A sweet wine is made from the blossoms. The root is roasted for a coffee-like drink. Many herbal remedies are based on this common plant. The leaves are a diuretic and supply potassium, which replenishes that washed out of the body with the urine. Here is a medicine whose side effects complement its main action.
Use: food, beverage, herbal, soil improvement
Discussion: The root penetrates hard pans (4810) withstands concentrated alkaline salts and increases soil permeability (5110). Dandelion is healing your yard by growing in it. When herbicides are sprayed on a lawn, soil fungi are killed, destroying the soil structure. So herbicides can encourage dandelions. Compost and soil acidifiers are better to discourage dandelions and stimulate grass.
Morning-glory (Ipomoea purpurea (L.) Roth)
Common Names: morning-glory
Family: morning glory
Indicator value: Tolerates low phosphorus (5110). The surface or lower soil layers compacted (4810).
Control: Hand pull, and hoe, then use clean cultivation to keep under control.
Allelopathy: Companion to corn in small quantities (1305), Morning glory stimulates the germination of melon seeds (4820).
Food: Take care to warn children not to eat the seeds as seeds are hallucinogenic.
Use: soil improvement, ornamental
Discussion: Morning-glory improves soil organic matter and improves soil texture.