Juncus ensifolius
Juncus ensifolius, commonly known as sword-leaf rush, is a clump-forming evergreen perennial that grows in dense tufts of upright stems. It is native to temperate climates throughout the Northern Hemisphere. Foliage is a bright grass-green color in summer, turning bronze or rust-colored in winter. Tiny, inconspicuous flowers are borne in clusters from late summer into fall. This is an excellent cultivar for narrow strips of turf, water gardens, and for ground cover in sunny to partially shaded locations. Cold hardy in USDA zones 4-11.
Sword-leaf rush is quite tolerant of dry conditions once established. It prefers rich, moist soils that are slightly acidic, but is drought-tolerant. Make sure the soil is draining well when planted in pots to prevent root rot.
Juncus ensifolius prefers full sun to partial shade, the more shade it is given the thinner and less robust the foliage becomes. However, when grown in full sun in a warm climate sword-leaf rush foliage becomes bronze and more delicate.
Juncus ensifolius is cold hardy to USDA zones 4-11 and can tolerate temperatures as low as -20°F (-29 °C). In warmer climates it can also tolerate temperatures as high as 80°F (27°C).
Sword-leaf rush tolerates indoor humidity levels, but prefers high outdoor levels, ideally between 40-60%. If indoor humidity levels become too low, it is possible to mist it once or twice a week.
Sword-leaf rush prefers fertile, humus-rich, slightly acidic, moist soil, but can tolerate damp or even dry conditions. It prefers a slightly acidic soil with a pH of 5.5-6.5, but is tolerant of a range of soil pH levels when grown in the garden.
Fertilization is not necessary for sword-leaf rush, however if you choose to fertilize, do not use a fertilizer that is high in nitrogen. A slow-release balanced fertilizer according to manufacturer directions can be applied every other month throughout the growing season.
Juncus ensifolius is typically pest and disease-free, however if grown in overly wet soils, it may become vulnerable to root rot or fungal diseases such as root rot and powdery mildew. To prevent these from occurring, make sure proper drainage is present and water is not allowed to stand. If pests such as mealybugs and aphids appear, treat them quickly by physically removing them and spraying the foliage with insecticidal soap.
Sword-leaf rush should be repotted once every two years, or when the roots begin to fill up and press against the sides of the container. Use fresh, well draining soil and make sure to water it thoroughly after repotting.
Sword-leaf rush requires little pruning, however if it begins to look ratty or spread beyond the boundaries of its designated space, it may be necessary to keep it in check. Clean-up pruning should be done once in the early spring.
Mulching is beneficial for sword-leaf rush, as it helps to preserve moisture and keep weeds away from the foliage. An organic mulch such as bark chips, leaf mold, or compost should be applied in spring or early summer.
Sword-leaf rush propagates readily from division. Choose divisions from clumps that are at least 3 years old, and gently separate the roots with a spade or garden fork. Plant divisions in well prepared soil, keeping the foliage at about 4-6 inches tall, and water them in thoroughly.
Sword-leaf rush typically does not require staking or other support, but in windy areas or exposed locations, it may benefit from lightly leaning stakes.
Sword-leaf rush does not have a true rest period, but its growth does slow as the days grow shorter and colder in winter months. During this time, it is best to avoid over-watering it, as this can lead to fungal disease.
Juncus ensifolius is not toxic to animals.