Overview of Digitaria simpsonii
Digitaria simpsonii, also known as Simpson's crabgrass, is a type of annual grass in the Poaceae family. This species is native to the southwestern United States and northern Mexico.
Common Names
In addition to Simpson's crabgrass, this plant is also commonly referred to as Simpson's fingergrass or purple crabgrass.
Appearance
Simpson's crabgrass has a dark green to purplish coloration, with slender stems that can grow up to 2 feet tall. The leaves of this grass are narrow and can vary in length from 1 to 5 inches. The seed heads are also quite distinctive, with a purple to reddish hue and a finger-like shape that gives rise to the common name "fingergrass."
Uses
In some regions, Simpson's crabgrass is considered a desirable plant for forage or grazing. However, it can also be a nuisance weed in lawns and gardens, as it can quickly spread and crowd out other plants. In traditional medicine, some species of Digitaria have been used to treat various ailments such as diarrhea, dysentery, and jaundice. However, there is not enough scientific evidence to support these claims for D. simpsonii in particular.
Growth Conditions for Digitaria simpsonii (Vasey) Fern.
Light Requirements
Digitaria simpsonii (Vasey) Fern. is a warm-season grass species that requires full sun to grow effectively. It can tolerate some shade, but full sunlight is essential for optimal growth. In areas with insufficient sunlight, the grass may become spindly and weak, making it more susceptible to disease and pests.Temperature Requirements
This grass species is adapted to warm climates and thrives in temperatures ranging from 75 to 85 °F (24-29 °C). Although it can tolerate temperatures as low as 60°F (15.5°C), growth is slower, and it may not establish as well in colder climates. Temperatures above 95°F(35°C)should be minimal.Soil Requirements
Digitaria simpsonii (Vasey) Fern. prefers well-drained soils that are rich in organic matter. The soil should be neutral to slightly acidic (pH 6.0-7.5) soil. The plant can tolerate compacted soils, but growth may be reduced significantly. The ideal soil type is loamy sand, with moderate fertility. In situations where the soil is sandy, application of organic matter or supplements of nutrients may be necessary. This grass species can tolerate saline soil environments.Water Requirements
Digitaria simpsonii (Vasey) Fern. requires moderate amounts of water to grow. The plant is drought tolerant, but prolonged water shortages can lead to slow growth and development. The frequency of watering depends on soil moisture and temperature conditions. It is recommended to water every 7-10 days when soil moisture is low.Nutrient Requirements
This grass species requires moderate to high levels of nitrogen for optimal growth. Additions of phosphorus and potassium may be necessary in soils that are low in these nutrients. The use of proper fertilization techniques, along with regular soil testing, can help to ensure that adequate nutrition is provided for the grass species.Cultivation methods
Digitaria simpsonii is a warm-season grass that grows best in areas with well-drained soil and full sun exposure. It is recommended to plant the grass in spring or early summer when the soil temperatures are consistently above 60°F. The planting depth should be shallow, about 1/8 inch. Once the seeds have been sowed, it is important to keep the soil moist for the next two to three weeks. The grass should germinate within five to seven days if the soil temperature is adequate.
Watering needs
Digitaria simpsonii requires adequate water to grow well, but it is important to avoid overwatering. The grass should be watered deeply, preferably in the morning, to allow sufficient time for the soil to dry before nightfall. The frequency of watering will depend on factors such as soil type, temperature, and rainfall. In general, the grass should be watered once a week during the growing season and every two weeks during the dormant season.
Fertilization
Digitaria simpsonii requires regular fertilization to maintain healthy growth. A balanced, slow-release fertilizer with an NPK ratio of 3-1-2 is recommended. The first application of fertilizer should be in early spring, just before the grass starts growing. Additional applications should be made every six to eight weeks throughout the growing season. It is important to follow the manufacturer's instructions for the appropriate amount of fertilizer to apply.
Pruning
Digitaria simpsonii does not require regular pruning, but it is recommended to keep the grass mowed to a height of three inches or less. Mowing should be done regularly during the growing season, every two to three weeks. This will help maintain a neat appearance and encourage new growth. If the grass becomes overgrown, it can be cut back to three inches in late summer or early fall. Pruning should be done with sharp shears or a lawnmower with a sharp blade to avoid damaging the grass.
Propagation of Digitaria simpsonii
Digitaria simpsonii can be propagated by several methods including seeds, plugs, and division. Understanding the characteristics of each method can help maximize the plant's propagation success.
Propagation by Seeds
Propagation by seeds is the most common and easiest method of propagating Digitaria simpsonii. Seeds should be collected in the fall when they mature and can be directly sown in the field, nursery bed or flats with good quality soil. Pre-germination treatments such as soaking in water or scarification can improve the germination rate. The ideal soil temperature for germination is between 20 and 30?, and germination can take from 5 to 21 days.
Propagation by Plugs
Propagation by plugs means planting of small plantlets directly into the soil. The plantlets can be grown from seeds in nurseries or trays using a good quality soil mix. The optimal planting time is in the early spring when the soil is moist, warm and temperatures range between 15 and 25?. The root system of the plantlets should be well-developed before planting in the field.
Propagation by Division
The propagation of Digitaria simpsonii can also be done by dividing the mature plants. It involves lifting the plants with a shovel or fork, dividing them into several pieces and replanting them into the ground or in pots. The best time to divide is in the early spring when the plant starts to grow actively, and the soil is warmer.
Disease and Pest Management for Digitaria simpsonii
Digitaria simpsonii is a hardy species of grass that is drought-resistant and commonly found in arid regions. However, like all plants, it is susceptible to a range of diseases and pests. Here are some common issues that may arise with this plant and ways to manage them.
Diseases
Fungal diseases are the most common problems that Digitaria simpsonii may encounter. Here are some typical diseases and their management techniques.
Fungal Leaf Spot
The symptoms of fungal leaf spot include small brown spots on the leaves that may join together to form large patches. Fungal leaf spots can be managed by removing the infected leaves and improving air circulation and drainage around the plant. Fungicides may also be used in severe cases of the disease.
Fusarium Root Rot
Fusarium root rot causes wilting and yellowing of leaves. The roots of the plant will appear brown and rotten. It can be managed by avoiding overwatering the plant and planting it in well-drained soil. The use of fungicides may also be effective in controlling the disease.
Pests
Despite being a hardy plant species, Digitaria simpsonii can be affected by pests. Here are some common ones and their management techniques.
Armyworms
Armyworms are caterpillars that can cause extensive damage to the leaves of the plant. They can be controlled by handpicking them from the plant or using insecticides specifically designed for this pest.
Grasshoppers
Grasshoppers are common pests that feed on the leaves of plants, including Digitaria simpsonii. These pests can be managed by reducing their numbers through physical removal or using insecticides that are designed to target grasshoppers.
Overall, the key to managing these pests and diseases is to maintain a healthy plant by providing it with optimal growing conditions, such as adequate water and sunlight, and removing any diseased or infected parts of the plant. Regular inspections of the plant, making note of any changes in its appearance or behavior, can help identify potential issues before they become widespread problems.
