How to Grow Asparagus Ferns
If you remember the seventies, then you remember fern bars. For everyone else, fern bars were upscale bars where upscale young people went to pick up or be picked up. As the name implies, the main ornamental item were large ferns. Ferns were popular in that era as houseplants. The most popular of them was the asparagus fern.
They are neither asparagus nor ferns
The asparagus fern looks very much like an asparagus plant and like asparagus is a member of the lily family. It is not a true fern. Its "fronds" are actually long stems with needle-like leaves. Unlike true ferns, the asparagus ferns grow from underground tubers. They also flower, something else you won't find on a true fern. The flowers produce berries that are first green, then turn red when ripe. Birds love them and help asparagus ferns spread by eating the berries and then excreting the indigestible seeds, usually far away from the original plant. The plants themselves are toxic for dogs and cats so you might want to either not grow them or hang them high that your pets can't reach them.
Grow them outdoors
Asparagus ferns are easy to grow. They are hardy in zones 9 through 11 where they can be grown outdoors year round. They are native to South Africa so it is not surprising that they are drought tolerant. They work well in xeriscapes because they prefer being dry. Plant them in rich, well-drained soil and water sparingly. Fertilize monthly with a balanced fertilizer. Asparagus ferns grow best in dappled shade but can tolerate full sun. If grown in sun, the plants tend to be bushier and more compact rather than sprawling. In a shadier location, try planting them along the tops of walls where they can trail over the edge. You will need to divide your ferns every three years or so to prevent them from crowding out surrounding plants. In some places of the world, they are considered an invasive weed which crowds out the native plants. They are not bothered by diseases or insects.
Grow them indoors
North of zone 9, asparagus ferns should be grown in containers and brought indoors during the winter. Use regular potting mix in the containers and place them in a semi-shady area outdoors. Indoors, they prefer indirect light or a north facing window. Fertilize your containers weekly with a weak fertilizer. Water regularly because containers dry out quickly. Bring your ferns indoors before the first frost in the fall. Keep them indoors until all danger of frost in the spring. Make sure that the room they are in is not too warm. Asparagus ferns prefer cooler temperatures. The room should be between 55°F and 70°F. They like being pot bound but you will have to divide them every two years because the mass of tubers will fill the container and prevent proper drainage. These ferns prefer to be dry, so if the soil in which they are planted doesn't dry properly, they will literally drown. When dividing your plants, replant them in the same size containers that they were in previously so that they can "grow into" them, rather than in smaller containers which they will outgrow quickly.
Asparagus ferns have been declared weeds in Florida, Hawaii and New Zealand.
Other than in xeriscapes, you don't see asparagus ferns much since their heyday in the seventies which is a shame because they are so easy to grow and make gorgeous houseplants. No one, I'm sure, misses fern bars.
© 2014 Caren White