Lafayette County Master Gardeners: “Asparagus Fern”

by Bronwynne Bailey

Asparagus fern (Asparagus Densiflorus Sprengeri) is not a fern at all, but a member of the Asparagaceae family. It is a close relative of true asparagus and is edible. Asparagus ferns are ideal for the patio where they are well suited for use in hanging baskets, mixed planters, or in individual pots. The cut stems may also be used as greenery in flower arrangements. They grow best in bright locations with a uniform supply of moisture. The plants have great drought tolerance, but they drop their modified leaves and stop growing when they get too dry. Plants can be kept over winter indoors by placing in the brightest possible location and keeping them slightly on the dryer side.

Growth Habits

Like our garden asparagus, the asparagus fern is a perennial in milder parts of the country. It will reliably overwinter in protected beds in Zone 8. Being frost tender, it will die to the ground if it is subjected to even a light frost. The roots will remain hardy to temperatures of 20–25 degrees Fahrenheit. For container-grown plants, take indoors before the first frost. The plant forms a greenish white tuber that looks just like a grape. When it emerges in the spring the shoots grow rapidly and form arching canes that are clothed in inch-long fake leaves called cladophylls. The cladophylls are modified branchlets while the true leaves take the form of small, soft spines. In late summer, plants that are at least a year old typically produce quarter-inch white, fragrant flowers followed by pea-sized red berries later in the year. The seeds sprout readily and are the most reliable means of propagation, although old plants can be divided. Asparagus ferns can attain great age and become family heirlooms. Mature plants will reach up to 2′ tall and spread to fill a 4’ area.

Soil Preferences

While it tolerates a wide variety of soil conditions and textures, make sure the planting bed or pot is well drained.

Planting Depth & Spacing

The crown of the plant should be placed at the top of the soil level.

Watering

Prefers medium warmth, regular watering in spring to autumn, and sparingly in winter. It is intolerant of direct sunlight and wet soils.

Fertilizing

Fertilize every other year or so in the spring.

Pruning

Pinch back stem tips as needed to maintain plant form and promote dense foliage growth.

Pests

Watch for slugs, mites, mealybug, and aphids. Leaf spot and root or crown rotting may occur. Leaf drop can be a nuisance when kept indoors, especially in winter.