Weeds in your Horse Pasture

Star of Bethlehem

A bulbous perennial frequently sold commercially as a spring flowering ornamental. It has escaped cultivation and can grow as tufts in lawns and landscapes in the early spring. Although it is pretty…

All parts of the plant are poisonous if ingested.

Reproduction is primarily by small bulbs formed around the base of a parent bulb. Bulbs are renewed each year. Young plants are noticeable in turf in the early spring and landscapes in late spring. Leaves are linear, and flowering stems are up to 30 cm high and leafless. The grass-like leaves are fleshy and dark green with a whitish grooved midrib. Ovate bulbs grow in clumps and are subtended by a fibrous root system. Flowers present from April through June, are bright, waxy, white, on branched, open, clusters on the end of leafless flower-stalks. The 6 petals are lanceolate-oblong and white above with a distinctive green stripe underneath. Seed pods are present mid to late spring. Fruit are three-lobed, egg-shaped capsules containing several seeds that are black in color.

Here is what they look like:


Black Swallowwort

A twining, vine-like perennial with stems 1-2 m long. Climbing stems can envelop small trees and other desirable vegetation in natural areas. Reproduction is by seed. Stems are mostly unbranched, twining, and nearly smooth. Leaves are simple, opposite, dark green, petiolate, oblong to ovate, hairless with entire margins. The leaf tip gradually tapers to a point, and the base of the leaf blade is rounded. Flowers are produced from June through September. Clusters of 6-10 flowers are located in the left axils on 0.5-1.5 cm long peduncles. Flowers are purple-black with a 5-lobed corolla. The lobes are fleshy, triangular, 1.5-3 mm long with tiny hairs on the upper surface and a fleshy inconspicuous 5-lobed disk in the center. The fruit grows in pairs. Each fruit is a smooth, slender, elliptic, dark brown pod, 4-7 cm long. Seeds are brown, flattened, 5-7 mm long egg-shaped, with a wing margin and a tuft of silky hairs at one end. Although primarily a wood land species, black swallowwort has become an invasive weed in recently cleared areas, conservation habitats, Christmas tree plantations, nursery crops, and other perennial crops such as alfalfa. It also grows in fields, pastures and waste places and along fence rows, often in sunny areas.


Slender Rush

A clump-forming, grass-like perennial, with narrow, wiry, rounded stems. Reproduction is both vegetative and by seed. Seedlings are small with slender grass-like leaves only 1 mm wide. Whitish auricles are present at the junction of the leaf blade and sheath. When the plant is mature the steams are round, hollow, wiry, and dark green. Leaves are basal and flat, inwardly rolled at the margins to almost rounded. Sheaths cover 1/3-1/2 the height of the stem and have thin dry papery margins with a pair of papery ligule-like auricles at the junction of the blade and sheath. Fibrous roots are present at the nodes of short rhizomes. Flowers occur from June through August and are produced in clusters near the end of the stems. Two leaf-like bracts often extend beyond the flower cluster. Flowers are small, greenish brown, with lanceolate sepals and petals. Fruit are small, orange-brown, egg-shaped capsules that split into three sections at maturity. Slender rush is a weed of turf grass, landscapes, and nursery crops, especially along paths and in gravel or stone driveways and roads. It also grows in pastures, meadows, and waste places, on both moist and dry sites. It is particularly successful in compacted soils.



A summer annual that usually produces a prostrate, mat-like rosette with steams radiating from a central point but can grow erect to 60 cm in height. The flattened leaf sheaths in the rosette are whitish to silvery. Reproduction is by seed; seeds germinate in early to midsummer when soil temperatures are above 64 degrees Fahrenheit. Goosegrass usually germinates 2-3 weeks later than crabgrass. For seedlings the first leaf blade is about 3-5 time longer than wide and opens parallel to the ground. Leaves are folded in the bud, lack auricles, and have a short, membranous, unevenly toothed ligule. Sheathes are smooth, prominently compressed, and light green to white at the base. For a mature plant the leaves are similar to that of the seedlings. The ligule is membranous, blades are folded along the midvein, smooth or occasionally harry on both surfaces, and have rough margins. The root system is fibrous. Goosegrass does not root at the nodes. Goosegrass will die after the first hard frost. Flowers are produced from June through September. Seed heads mature in late summer through early autumn but persist into winter. Seed heads consist of 2-3 spikes in clusters at the top of stems. Spikelets are flattened in 2 rows along the spike and contain 3-6 reddish brown to black seeds. Goosegrass is common in turf, nursery, landscape, and agricultural crops. It is also found in gardens, roadsides, and waste areas on most soil types. It tolerates close mowing, compacted soils, and drought.



A mat-forming, stoloniferous, course-textured perennial. The foliage is greyish green. Stems are erect when young but become branched with age, spreading and bending, and rooting at the nodes. Tips of the developed blades strongly arch towards the soil. In unmowed areas, nimblewill grows from 20 to 60 cm high. Reproduction is from seeds and stolons. In seedlings the first leaf blade in linear, tapering gradually to a point, about 5 times longer than wide. It opens parallel to the soil surface and eventually arches downward. Leaves are rolled in the bud; auricles are absent, and the ligule is membranous, very short, and toothed across the top. A mature plant is very similar to a seedling. Horizontal stems root at the nodes, producing a fine , fibrous root system. Roots are weakly connected to the stolons and are easily pulled from the ground. Nimblewill flowers from August to October. The seed heads are spike-like panicles that are produced both terminally and axillary nodes. In the winter nimblewill turns brown but mats of stolons persist and re-sprout the following spring. It thrives on moist, right soil, often in the shade.



A winter or summer annual. Seedlings develop into a basal rosette. Mature plants produce and erect central stem with a terminal panicle of inconspicuous flowers. Reproduction is by seed; seeds germinate in late summer or spring. Late summer germination results in overwintering rosettes. Stems are erect, bristly hairy, with many small flowering branches in the upper portions. Leaves are hairy, alternate, numerous, and crowded along the stem. Blades are sessile, linear to elliptic, broadest at the apex and tapering at the base. Leaf margins can be entire but are usually toothed. When growing as a winter annual, the basal rosette is produced in late summer. After the stem elongates, the basal leaves deteriorate. Stem leaves are lanceolate to linear, with nearly entire margins. Leaves become gradually smaller up the stem. Roots are short taproot with secondary fibrous roots. Flowers are present from July through October. Plants turn brown before fruit dispersal.


Now that you know more about the weeds you may encounter in and around your horse pasture, tune in again next week to find out how to safely and effectively get rid of weeds.

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Shelly Ingram

I am a third generation horsewoman; My father operated a 50 horse boarding and training facility in northern California, where he specialized in re-training spoiled horses. I was his demonstration rider and general assistant in all aspects of running the ranch. I went on to work for several major show and race horse trainers, eventually opening my own barn where I focused on Junior and Amateur riders. I have trained numerous champion horses and riders on all levels and in variety of disciplines. I have also worked as a journalist and have more than a decade of experience in land use planning.

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