Thursday, February 12, 2015

ASPARAGUS FERN (Asparagus aethiopicus)

It is useful to have an old potted asparagus fern around in the garden.  They make a nice full display as well as being a source for long dangling cuttings of greenery to insert in floral arrangements.  This plant,a native of South Africa, is not in the fern family, despite its name, but is a relative of the edible asparagus.  It has a couple of cousins that are also common in warm climate gardens........the Fox Tail Fern and the Climbing Asparagus Fern that I associate with old time bridal bouquets and boutonnieres. 

The Asparagus Fern is a natural for hanging pots but also is used as a ground cover.  Personally, I would not use it for a ground cover as it can get a bit messy looking with age.   I see on the internet that there is a problem with it getting invasive in Florida.  Another reason for not planting it out in the ground.  Birds could spread the seeds I guess but I have never noticed the fruit eating birds taking any interest in it.  I like to grow Asparagus Ferns in a large pot so that I have more control over it plus I can move it around for special garden events if wanted.  I rarely notice any bug or disease problem with it.  If it does get a problem it usually means it is getting too much water and not enough sun.  They do not like wet feet.  If I use the plant indoors for a special event, it is only for a day or two at most.  Longer than that and the plant will be dropping yellow needles all over the place.

Asparagus Fern can be propagated by division but I much prefer to grow them from seed so that I get a pretty, fluffy and upright plant to start off that will stay attractive for a long time.  As the plant grows older, it produces hundreds of white grape looking tuberous roots.  It is one of the mysteries of potting plants. Where does all the potting media disappear to?  You can plant a young Asparagus Fern in an azalea pot full of potting mix and in a few years the pot is just jam packed with the "white grape" tubers and no potting mix to be seen.  It will not stop there.  The plant keeps on producing its little tubers so that the plant root ball is lifted up right out of the pot and can grow several inches above the pot rim if left to do so ending up looking plain ugly.  You can see this tuber growth in older plants grown out in the landscape too and it does not look pretty.  This is when growing the Asparagus Fern in a pot helps for easy plant management.  It is time to be the boss and cut the plant down to size.

First, you give the overgrown Asparagus Fern a haircut.  This is done by cutting it totally bald.  You do not want any bits left sticking up and looking unattractive in the next new growth. Next, you remove the root ball from the pot and cut all those tubers off, keeping a small "cake" of roots, 2-3 inches deep and about  4-6 inches across.  A good carving knife or machete is the best tool for this job.  It is rather like cutting bread.  Repot the remaining "cake" of roots in fresh potting mix, fertilize and water well and you are done.  In a few weeks the new fronds will be coming out and in a few months you would never know that the plant had undergone such intensive surgery.  If a plant is not outgrowing its pot but looking very sad and straggly, I do just the haircut and fertilize part to get it looking good again.  Asparagus Fern loves getting fertilized and really responds to it with  lots of new growth.

The old-timer, before it meets the knife.
The same plant, after the haircut.
The root ball full of "white grape" tubers
The roots after surgery with the resulting "cake" on the left.
The root "cake" repotted.
New growth two weeks later.

To grow new plants, gather the little round red fruit and plant them in some potting mix.  You can rub the red fruit part off  the black seed inside or not worry about it.  I might also soak the seeds in water for a few hours before planting but either way, the seeds sprout quickly and easily.  After they have put up a few tiny fronds I transplant them into a 4 inch pot.  In a few months, when the small plant is full and bushy, I will transfer them to something bigger.  They always look nice in an azalea pot but I will use a big 4 gallon pot for the old timer that I want to keep for long dangling greenery.


PS    May 2019
Here is a picture of a recent visitor having a nap among my baby Asparagus Ferns.  The pots are 4" size so you can figure out how big the cane toad is.  As soon as the sun moved over to the nursery area he moved on.