How to Care for an Asparagus Fern
The asparagus fern (Asparagus plumosus) is an ornamental relative of edible asparagus that provides lush greenery, whether grown outside or in a pot indoors. This plant, formerly classified as Asparagus setaceus, grows in U.S. Department of Agriculture hardiness zones 9 to 11, according to North Carolina State University Cooperative Extension.
Asparagus densiflorus is another variety of asparagus fern that is also hardy in USDA hardiness zones 9 to 11, notes Arizona State University. Indoor and outdoor ferns require similar care to grow well and produce lush foliage.
Asparagus Fern Growing Environment
Place potted ferns, so they receive bright but indirect sunlight, either indoors or outdoors. Plant garden ferns in an area with bright, filtered light, such as under a tree. If you notice the fern's needles are yellowing, it may need more sunlight.
Only plant ferns in the ground if temperatures in your area never drop below 24 degrees Fahrenheit, advises Missouri Botanical Garden. If you live in a colder climate, you can still grow an asparagus fern outdoors, but grow it in a pot, so you can bring it in to avoid frost damage. Bring potted outdoor ferns indoors before the average nighttime temperatures dips below 50 degrees Fahrenheit. Move them back outdoors in spring after frost danger passes and temperatures climb above 50F.
Asparagus ferns prefer well-drained, neutral or slightly acidic soil. Improve fern health and growth by adding plenty of compost to the soil and cover the soil with mulch to help keep the soil moist, advises Marin Master Gardeners.
Plumosa Fern Care
Water potted plants regularly to keep the soil moist. Water garden plants once or twice a week, so the soil doesn't dry completely. Asparagus ferns are moderately drought tolerant, but they will grow at a slower rate without sufficient moisture, notes the University of Florida.
Asparagus ferns like high-nitrogen soil, so be sure to fertilize in the late winter and again mid-summer. Add compost around outdoor planted ferns each spring to replenish the natural nutrients in the soil. Asparagus ferns don't go fully dormant in winter, but they do benefit from a rest period during which they require less water and no fertilizer.
Prune the fern by removing dead stems and branches. About every three years, cut back both garden and potted asparagus ferns to the root in early spring before new growth begins, advises Arizona State University. The ferns send up new foliage that's healthier and brighter green after pruning.
Asparagus Fern Considerations
Potted asparagus ferns may quickly become root-bound. When this occurs, the University of Florida recommends removing the root ball and dividing it. Replant one division of the root ball. You can discard the unused divisions or re-plant them in another pot.
Frost may kill your asparagus fern. However, as long as temperatures remain above 24 degrees Fahrenheit, the roots will likely survive, and the fern will return when temperatures rise in the spring. Some locations, including Hawaii, Florida and Southern California, consider Asparagus densiflorus to be an invasive species, advises Missouri Botanical Garden. Check your local guidelines before planting this fern in your garden.
Use caution when planting asparagus ferns around your pets. Some cultivars, such as Asparagus densiflorus 'Sprengeri,' have berries that are toxic if ingested and can cause vomiting, diarrhea and abdominal pain in your cat or dog, advises Louisiana State University. Contact with the fern also can cause dermatitis.
- Asparagus ferns don't go fully dormant in winter but they do benefit from a rest period where they require less water and no fertilizer.
- Asparagus ferns are not edible and can be toxic if ingested.
Maureen Malone has been a professional writer since 2010 She is located in Tucson, Arizona where she enjoys hiking, horseback riding and martial arts. She is an outdoor lover who spends her weekends tending her raised garden and small orchard of fruit trees.