Written by Fergus Masons • December 28 Spider Plant
Many tropical or subtropical plants need a lot of care and attention to grow successfully, but there’s a much easier way to add a hint of the exotic to your home. The spider plant is a striking-looking specimen that does well as an indoor pot plant and has been popular in the USA for decades. Here’s a quick guide to this interesting species.
The spider plant, Chlorophytum comosum, is a native of tropical and southern Africa. It’s a small perennial evergreen, and can reach up to about two feet high. Its most conspicuous feature is the spray of long, slim leaves, which make up most of its bulk – there isn’t much of a stem, and the leaves grow directly from the base of the plant.
It’s the leaves that make spider plants so distinctive. They’re narrow and blade-shaped, and can reach a length of 18 inches or more in a large plant. At most they’re around an inch wide and they taper to long, fine tips. There are varieties with plain green foliage but these are rarely seen; almost all of those sold as houseplants have variegated leaves. The two most common are “Variegatum”, which has dark green leaves with white margins, and the larger “Vittatum” with lighter green leaves with a while central stripe. The leaves of a healthy plant take on a characteristic arched shape, growing up from the center then curving over and down. This makes them an ideal choice for hanging baskets, as the leaves will hang down past the basket in an attractive cascade.
One of the most interesting features of the spider plant is its method of reproduction. When the plant flowers it extends a long stem, which then displays small white flowers along its length in clusters of one to six. Fertilized flowers produce small capsules of seeds, which eventually break open to scatter the seeds on the wind. That’s not the only way the plant can spread itself though. The flowering stem, like the leaves, eventually grows too long to support itself and droops towards the ground. As it grows it puts out branches, and a small plantlet develops at the end of each. It’s these plantlets that give the species its name – they look like green spiders descending from the stem on a thread. When each plantlet touches the ground it puts out roots; it can act as a sucker from the main plant, but if the stem is cut it will grow independently. For gardeners these plantlets are a useful source of new spider plants, as each one can be cut away and planted in a pot.
If you’d like a spider plant at home, the good news is they’re remarkably easy to grow. Despite their African tropical roots they can tolerate a wide range of conditions. They’re not likely to survive freezing temperatures, but should be able to survive outside in USDA hardiness zone 8 or higher. They’re likely to thrive in any temperature found indoors.
Like many houseplants the key to success with spider plants is to get the right size of pot. This species does best when it’s slightly potbound, so don’t give it too much space. The roots are another distinctive feature; they’re thick and fleshy, almost like slim tubers, and in the wild the plant uses them to store moisture during dry spells. If you ever find yourself lost in the South African bush look for spider plants, because chewing their roots is a great source of liquid! If your aims are less adventurous just keep an eye on the pots your plants are in; when the root ball begins to protrude over the edge of the pot it’s time to move the plant to a larger home, because if the tangle gets too thick water won’t be able to reach the roots at the center.
A shortage of water is the most common source of problems with spider plants, and it can affect them even if you think it’s getting enough. Don’t pour water onto the leaves, because little of it will reach the soil; most of it will either run down the leaves (and probably drip on your floor) or evaporate from the surface. Instead pour it directly on the soil. If most of the surface is covered with roots consider repotting; if the surface dries out very quickly after watering that could also be a sign that the plant’s getting cramped.
In summer your plant should be watered regularly enough that the soil stays moist (but not waterlogged) to the surface. In winter let the top layer dry out slightly between waterings. You also need to watch the humidity in winter; it’s too low in most homes, so mist the plant every few days. This will keep the leaves in good condition and also deter spider mites, which occasionally infest spider plants.
Water quality is another thing to keep an eye on. Spider plants are sensitive to salts, especially anything that contains chlorine or fluorine. Unfortunately that includes most tap water, and it can affect your plant. Look for brown tips to the leaves; this could mean there’s a build-up of chemicals in the soil. To avoid this problem leave tap water to stand overnight in an open jug, so the chlorine has a chance to evaporate out. Alternatively use filtered or distilled water, or collect rainwater; it’s ideal for watering plants. If your spider plant already has brown tips try watering very heavily then allowing the pot to drain thoroughly – that should leach the salts out of the soil. Letting it drain is vital though, because spider plants are vulnerable to root rot.
By the time your plant is around two years old it should be fully mature and plantlets will begin to appear. If you wait until these develop roots you can cut them off the stem and plant them in small pots; alternatively you can place pots below the plantlets as they descend on the branch and let them establish themselves naturally, then once they’re firmly rooted cut the stem.
You can also divide an adult plant while you’re repotting it. Split the leaves and root ball into two or three pieces then plant each one in a new pot – it’s that simple.
One final useful fact about spider plants is that they can actually improve your environment. Many building materials release formaldehyde gas, especially in new homes. Formaldehyde is a natural substance and all living things produce it – even you – but at higher levels it can cause health problems and even cancer. The good news is that spider plants are very efficient at absorbing it from the air, so as well as their attractive looks they also have real benefits for your health. That’s just one more reason no home should be without one of these delightful plants.