Many of the plants in my sunroom in the winter are ones that I use both indoors and out. Some of them are old tried-and-true favourites, such as the asparagus fern. These are dependable, easy-to-grow plants that can put on an attractive display of foliage.
An asparagus fern is delicate looking (although it really isn’t) and feathery. The foliage is produced on long, thick wiry stems which begin by being upright but become pendulous as they lengthen, some growing well over a metre in length. The small leaves, which can be a couple of cm long and a quarter of a cm wide, are produced along the stems in bunches and are bright green.
The asparagus fern gets its common name because of the foliage, although it is not really a member of the asparagus plant family at all. It is grown outdoors in tropical areas but is definitely not hardy in our area.
The most common form of asparagus fern is Asparagus sprengeri, which produces the longest fronds. The plants grow from fleshy rhizomes and soon form gigantic balls of fibrous roots. This rampant root growth means that roots and rhizomes soon fill a pot; this is one plant that needs to be divided and repotted frequently. The foliage also grows quickly; if the branches get too long and cascade down too far they can be trimmed off, which will cause the stems to branch and the plant to become bushier. Asparagus ferns are heavy feeders and need to be fertilized frequently; the foliage becomes quite pale green if nutrients are lacking.
Another variety of asparagus fern is Asparagus densiflorus, sometimes called the foxtail fern because of its unusually shaped fronds. While the ordinary asparagus fern has a pendulous, informal growth habit, the foxtail fern produces stems of foliage that are round in shape because the leaves are attached all the way around the stems, creating stems that do resemble a fox’s round tail. The foxtail fern also has shorter fronds and therefore has a more upright growth habit, although some of the longest fronds do occasionally become pendulous.
All asparagus ferns like rich, well-drained soil. I have grown them successfully in a good-quality soilless mix which is peat based, and some gardeners add compost to the mix. The plants require a consistent fertilizing regimen and like their planting medium to be kept moderately moist and resent having it dry out. Yellow leaves on an asparagus fern usually indicate that the soil is too dry. These will not recover and will drop off the plant, so don’t allow the soil to become too dry.
Asparagus ferns make good houseplants but in the last few years they have been used increasingly outdoors in containers — in particular Asparagus sprengeri — often referred to in greenhouses as a basket stuffer.
Used as a filler in a large outdoor container, the foliage acts as a foil for the other plants in the container which usually have larger leaves. It also can be used by itself in a hanging basket, but whatever way it is used, it must be high enough off the ground to accommodate its long pendulous branches. Outdoors, the plant should be protected from the strongest rays of the midday sun but will be happy receiving some direct sun. Indoors, asparagus ferns will tolerate some direct sun, particularly in the winter, but will also perform well in bright, indirect light.
If you see these plants at a garden centre, pick one up and add it to your indoor landscape with the view to using it in an outdoor container when spring arrives. By springtime it might even have grown large enough that you will be able to divide it (asparagus ferns are easy to propagate by division) and wind up with more than one attractive specimen for your garden.