The genus Asparagus has several plants. Commonly known as Asparagus fern, these plants are categorized into different varieties. Some of them are Asparagus aethiopicus, Asparagus plumosus, Asparagus virgatus, Asparagus densiflorus and Asparagus setaceus
This article focuses on Asparagus fern plants, their history, propagation, caring, varieties, and uses.
In spite of its attractive name, Asparagus fern is not a true biological fern. Rather than developing spores, these plants set seeds. Being tiny protrusions, the true leaves are barely noticeable. The visible false leaves are just flattened stem portions or cladodes.
These evergreen herbaceous perennial plants grow vigorously. Due to this growth habit, people living in USDA Zones 9 – 11 (Texas, Hawaii, Florida Etc.,) consider them invasive. However, you can grow them confined in sturdy planting pots.
Indigenous to eastern and southern Africa, some varieties are toxic to both animals and humans. Make sure to keep children away from these ornamental plants.
History and Characteristics of Asparagus Fern
In the USA, the Asparagus fern plants found their way through Europe from Africa. They have been largely commercialized as ornamental plants in the late nineteenth century.
In commercial markets, you can most widely find A. setaceus. A. retrofractus and A. densiflorus. Many species of these plants thrive in wildlands. Some of them like A. racemosus and A. africanus have medicinal properties.
Generally, these plants grow in upward fashions like shrubs. The delicate branches sprout out in multiple layers. Under ideal conditions, they develop white blossoms and red, orange, or purple berries. Adding to the ornamental interest, these berries develop seeds that can be stored for future propagation.
Being dioecious, both male and female plants produce their respective flowers. However, only the female plants can develop fruits. While purchasing, it is impossible to differentiate between male and female plants (unless fruiting occurs).
Normally, the Asparagus fern plants grow about three feet tall and spread about the same measure. Under optimal conditions, they may grow more extensively. The normal life span of these plants is about 10 years. With good maintenance, their life span may extend by a few years more.
Propagation of Asparagus Fern
In USDA Zones 9 – 11, asparagus fern grows outdoors as a perennial. In other zones, people commonly grow them indoors in pots or as annuals in the garden.
These plants thrive well in dappled shades. They can also tolerate a little bit of sunlight. However, keep them away from direct, hot, bright sunlight.
Temperature and Humidity
Generally, Asparagus fern plants do well in temperatures around 70 F. They cannot withstand temperatures below 55 F for a long time. In summer, if you place the indoor container plants in shady porches or a greenhouse, they respond positively with prolific growth.
For indoor plants, use well-draining loose potting soil. Outdoor plants prefer to grow in well-draining soil that is rich and slightly acidic with a pH range of 6.5 – 7.0. These plants can also thrive in slightly less favorable soils.
You can purchase the seeds online or use your own saved ones. Each berry has about one to three seeds. As germination is not guaranteed, this method may prove to be challenging.
Before planting, scrape the hard outer shell of the seeds with sandpaper. If you cannot handle them, place them in a bag containing a little sand and shake well. Then, soak them in a jar of water overnight. By weakening the outer shell, this process helps the seeds to germinate faster.
For indoor growing, plant the seeds in seed starter trays or grow disks. If you live in Zones 9 – 11, you can plant the seeds directly in the gardens.
1.) Moisten the soil surface by applying water.
2.) Sprinkle the seeds on the soil surface and gently press them down with fingers
3.) Cover them barely as they need light for germination
4.) Maintain the soil moisture by applying water regularly. Allowing the soil to dry out completely can be risky.
You can expect germination in a month or two. You can also further quicken the germination by maintaining the soil temperature about 70 F – 80 F consistently.
Generally, Division is the easy, fast, and more successful method for propagating Asparagus fern plants. In the early spring, begin this process carefully.
1.) Select a healthy mature plant and dig it out as a whole.
2.) After inspecting the tuberous roots, cut off the infected/damaged portions carefully with garden knives.
3.) Using a good-quality shovel, divide the healthy roots into several sections. Make sure each section has at least a couple of shoots.
4.) According to the zone you live in, replant each section into individual planting pots or shady locations in the outdoor spaces.
5.) Maintain the water moisture by watering regularly. Avoid over watering as it can cause waterlogging.
Caring Asparagus Fern Plants
While working in the gardens, it is recommended to wear garden gears and use garden tools. In addition to enhancing personal safety, this prevents plant damages to a large extent.
Focusing on stems, mist the plants every day with water. These plants tend to thrive well in warm and humid environments. Upon water shortage, they turn brownish. So, never allow the soil to dry.
Using good quality weeders, remove the weeds regularly. Otherwise, these weeds may compete with plants for water and invite pests. Mulching prevents weeds and also helps to retain the soil moisture.
In summer, feed these plants weekly with half-strength all-purpose liquid plant food. As the growth slows down through fall and winter, gradually decrease the feeding frequency to 2 – 3 months.
Spring is the growing season for plants. Hence, pruning in spring helps the plants to grow fresh. Using garden shears, cut off the brown cladodes or other decayed parts from the base.
In addition, remove the dead woods and debris regularly. This helps to increase airflow and prevent common plant diseases.
In winter, the indoor plants tend to shed some cladodes. This is one of their common characteristics. Hence, choose a suitable location for placing the pots as deep cleaning may be required.
The roots of these plants can easily burst through thin plastics pots. Hence, use large sturdy pots that can accommodate mature plants. Make sure they have good drainage facilities.
Alternatively, start with small pots and transplant to larger ones as the plants grow. However, this is not an effective method as the plants have to go through transplant stress.
Generally, the Asparagus Fern plants do not develop blossoms and berries often. However, if you happen to see berries, try collecting seeds. Wait till the berries soften and decay out. Then just pick them up. Wiping the berry pulp off, dry the seeds in a dark, cool and dry space.
As a general rule, keep the berries, seeds, Etc., away from the reach of children and pets.
Pests and Diseases
With indirect lighting, a wet environment, and favorable temperatures, Asparagus Fern plants are prone to attract some insects and diseases.
Aphids, whiteflies, spider mites, mealy bugs, Asparagus beetles (spotted asparagus beetle), etc., can often trouble these plants. Under moist conditions, these plants attract snails and slugs easily.
Most commonly, these pests chew through the foliage. Some insects like aphids suck the sap out of the infected parts. As a result, the affected parts shrivel and die off.
If insects like snails and slugs are less in number, just dispose of them by hand. Otherwise use Diatomaceous Earth to kill them effectively.
You can treat most insects including aphids with neem oil sprays or insecticidal soap solutions.
Asparagus Rust (Puccinia asparagi)
Under high humid conditions, this disease readily infects plants. The infected parts develop yellow or orange pustules and die back with time.
Using clean and sharp garden shears, cut off the infected plant portions. Dust the plants with sulfur. Most importantly, regulate the irrigation.
Cercospora Blight of Asparagus (Cercospora asparagi)
This disease infects plants in high humid conditions. Through rain and wind, the lesion spores spread quickly to other plants.
The affected parts develop gray or tan oval spots with reddish-brown or reddish-black borders. These symptoms progress further to upper parts from lower parts of the plant.
As a perfect cure is not available, remove and dispose of the infected plant immediately.
Phytophthora crown and spear rot (Phytophthora spp)
This disease infects plants in wet and soggy environments. The infected plants develop soft and watery lesions mostly on the bottom portion of stems, near the soil surface.
Treat the infected plants with copper fungicides. Avoid over-watering.
Cultivars of Asparagus Fern Plants
Asparagus Densiflorus – Myeri (Foxtail Fern)
When shopping, you may see variations of this cultivar such as Myers, Myersii Etc., You can purchase seeds online also. This variety of plants grow about two feet tall and spread about 3 – 4 feet wide.
Resembling pine needles, the conical-shaped stems are densely packed with cladodes (Flattened stem portions). In fact, the name “foxtail fern” itself is derived from the spade of these conical-shaped stems.
In summer, these plants develop white flowers following which, the berries are formed in the fall.
Asparagus Densiflorus – Sprengeri (Emerald Fern)
This mounding variety of plants grow about 1 -2 feet tall and spread about 3 – 4 feet wide. Resembling small pine needles, the arching stems are loosely packed with cladodes.
As the plants mature, they become woody. Usually, the blooming season is summer and the berries follow the flowers in the fall.
Also known as Asparagus plumosus or Protasparagus setaceus, this variety closely resembles typical fern in appearance.
The plants have climbing layered stems. In fact, the pretty-looking stems are covered with tiny soft needles. So, be cautious while handling them. With age, the stems can grow a few feet long. For denser growth, just prune them every spring.
Generally, the Asparagus Fern plants are considered toxic to both humans (especially children) and pets.
Most commonly, sap contact can cause dermatitis and skin irritation in humans. In addition, the prickles’ may lead to severe mechanical injuries that may take a long to heal. This results in further sufferings like feeling uncomfortable while sleeping, eating, or working,
Generally, the pets suffer from Allergic dermatitis due to dermal exposure (contact with these plants). In most cases, the pets tend to swallow berries playfully. As a result, they may suffer from gastric disorders such as abdominal pain, diarrhea, or vomiting.
During summers, Asparagus Fern plants are primarily grown as filler plants in mixed flower containers. They fit well in window boxes, wall boxes, hanging baskets, and all kinds of planters
For decorating patios, just exhibit them in simple hanging pots. For simple arrangements, just allow them to trail across an accent table or shelves. In either case, these plants won’t fail to impress you and your guests!
Interestingly, you can grow them alone or interplant them with large shade-tolerant flowers in partly shaded spaces. While doing so, make sure to choose combination plants with a little bit of stature like tuberous begonias. otherwise, these plants can simply overpower the combination plants with their vigorous growing habits.
Asparagus species have many biological properties including anti-inflammatory, immunostimulant, antioxidant, antihepatotoxic, antibacterial, and reproductive beneficial ones.
Among them, experts have selected five species for anticancer activities after the scientific examination. They are A. africanus Lam., A. racemosus, A. laricinus Burch, A.densiflorus (Kunth) Jessop, and A. officinalis L.
In most parts of the world, Asparagus species are used to treat urination problems, pulmonary infections, diarrhea, dysentery, skin diseases, andrology and gynecology problems. They are also large widely used as antiepileptic and diuretic agents.
Some Mexican physicians use the decoction of the branches to treat pulmonary infections and the decoction of roots to treat diuretic problems.
In Tanzania, some people use Lobedu drink (cold infusion of stems and leaves) to cure malaria.
Some east Asian countries’ home medicines include milk (boiled with root tubes and sugar) to treat diarrhea and dysentery.