(Howdy to visitors from Homegrown Evolution!)
Although we can't be certain about the location or severity of the upcoming Zombie Apocalypse of 2014, we have a fairly good idea what it's going to involve: there will be zombies, brains will be eaten, civilization as we know it will end, and people will need to be resourceful. And also, obviously, we know it's going to happen sometime in the year 2014, 'cause otherwise the name makes no sense.
Though food-producing plants like potatoes and corn will be of primary importance in the days and months immediately following the rise of the zombie menace, there are other plants, including many sometimes grown as houseplants, which may also prove useful in obvious and non-obvious ways. I have collected a list here. The reader may wish to acquire and begin growing several of these immediately, just to be sure to have enough on hand when the time comes: we only have four years, give or take, so people may need to start propagating some of the slower-growers now.
Please leave a comment if you have any additional suggestions. I'm very interested in everyone's thoughts about the subject.
Abutilon cvv., with their relatively broad, fuzzy leaves, can be used as toilet paper, according to my dad. He was referring to Abutilon theophrasti, or velvetleaf, a common agricultural weed here in Iowa, but I'm pretty sure the more ornamental Abutilons would work. And who wants to survive the zombie apocalypse without toilet paper, am I right?
Agave species can be planted near the home as a first line of defense against zombie attack. Obviously Agaves will not kill the zombies, since zombies are already dead, but it'll slow them down -- the spines can snag clothing and body parts, slowing down attackers, and in the case of sufficiently dense plantings, attacks might be stopped altogether. In areas where Agaves are not hardy, they may still be useful houseplants: the terminal spines of Agave leaves may be removed and used as sewing needles, and the fibers of dried leaves can be spun into coarse but strong ropes. Larger species like A. americana are most efficient for such uses, but other Agaves can be used as well.
Aloe vera is widely respected for its ability to soothe and heal burns, which is very useful if your zombie defense system includes flamethrowers. As your zombie defense system should.
Zombie-resistant fortifications are likely to be airtight or nearly so, both to keep out the stench of rotting zombie parts on your Agave-planted perimeter and to keep zombies from detecting the presence of your delicious, delicious brains. Plants like Chlorophytum comosum will help to improve the air quality of such tight quarters, decorate your living space, and continually produce oxygen so you don't accidentally suffocate while hiding from the zombies.
Cissus quadrangularis has been used, historically, to speed healing of broken bones and injured tendons. It is currently used in dried, processed form as a dietary aid among the bodybuilding community.
Dieffenbachia canes, when chewed, cause pain and swelling in the mouth and throat, potentially leaving the victim mute for extended period. Fed to zombies, this will quiet their moans of "Braaaaaaains! Braaaaaaains," enabling you to sleep comfortably, safe in your defensive bunker.
Effective as your defensive perimeter of Agaves may be, the zombie body parts they accumulate will begin to stink and rot over time, and with stink and rot come flies. Dionaea muscipula, in large enough quantities, can eliminate said flies and protect you against the diseases they transmit, as well as the annoying buzzing sounds they make as they fly around.
The thorns and sap of Euphorbia grandicornis are capable of deterring or capturing zombies, as with Agave spp., preventing them from getting close to your bunker.
In the event that the zombies breach the Agaves and/or Euphorbia grandicornis, your first line of defense, you can use Euphorbia tirucalli as a backup: when the sap contacts zombie (or human) eyes, it causes temporary blindness and searing pain, potentially for several days, enabling you to repel the attack or relocate with significantly less risk to you and the other survivors in your bunker. To use, simply cut a few branches of the plant and fling them repeatedly in the direction of the zombies until sap contacts the zombies' eyes. (WARNING: Do not fling sap unless you, and all humans in your vicinity, are wearing goggles or other protective eyewear. Wash all exposed body parts extremely well following the use of Euphorbia tirucalli in defense.) Additionally, processed sap of this plant shows potential as a fuel source, which may be used to power generators or vehicles. This is likely critical, since power plants and oil refinery operations will likely shut down shortly after the existence of zombies becomes public knowledge.
The sharp marginal spines on Pandanus can deter or slow zombie attacks, as for Agave spp. The leaves can be dried and spun into ropes, or used fresh as a water-repellent shelter for food or other valuables. Some Pandanus species, like P. amaryllifolius, are used in cooking to impart a sweet flavor and aroma to cakes, breads and meat dishes.
As for Euphorbia tirucalli, though less effective as a form of defense and possibly more effective as a fuel source.
Plectranthus amboinicus has a pungent odor similar to oregano, and is used as an oregano substitute when cooking. As spices will probably be difficult to come by once civilization has shut down, this is a cheap way to maintain a little bit of flavor in one's diet. The smell is extremely strong, and may partly mask the odor of rotting corpses from the front lawn. The oil is said to be effective at relieving arthritis pain when applied directly to the skin. As a very tolerant plant which grows quickly, it also has the ability to clean and oxygenate the air, as for Chlorophytum comosum.
Salvia elegans can be used in cooking to impart a pineapple aroma to food; one can also make a refreshing and anxiety-reducing tea from the leaves. The leaves may also be somewhat useful in masking the scent of dead bodies, as for Plectranthus amboinicus. Its quick growth also oxygenates and detoxifies air. Hummingbirds are attracted to the bright red flowers, which appear in late summer into fall, thus the plant may also be grown outside (it's even perennial in warmer climates) and used as bait for catching hummingbirds to eat. (What's for dinner? Pineapple upside-down hummingbirds!)
Spathiphyllum spp. are relatively easy-care, attractive green plants with a high capacity for air filtering and oxygenation. They are frequently given as funeral gifts in pre-apocalyptic America, and may be useful for expressing condolences to other groups in other bunkers following zombie attacks, facilitating trust between survivors and forming bonds which will help to rebuild civilization after the zombie threat has been eliminated.
Citrus / Fortunella cvv., citrus fruits. (culinary, medicinal, environmental) (thanks, Daphne!)
Colocasia esculenta, taro. (culinary, shelter) (thanks, Taylor!)
Cordyline fruticosa, ti plant (culinary, shelter, clothing, alcohol, fuel)
Dioscorea bulbifera, air potato. (culinary, visual camouflage) (thanks, Errant!)
Dracunculus vulgaris, voodoo lily. (olfactory camouflage?) (thanks, Kenneth Moore!)
Musa spp. / Ensete spp., banana. (culinary, shelter)
Ocimum basilicum, basil. (culinary, environmental)
Opuntia spp., prickly pears. (culinary, defense/offense, livestock feed) (thanks, Andrew!)
Salvia officinalis, sage. (culinary, environmental)
Sansevieria trifasciata cvv., snake plant, mother-in-law's tongue. (fibers, environmental)
Yucca guatemalensis, spineless yucca. (fibers)
Zingiber officinale, ginger. (culinary, environmental, medicinal)
P.S. in response to criticism on a forum I don't want to register for just to make this one point and then never visit again: Yes, I know none of these would survive outside in a northern winter. "Houseplants" is in the title for a reason.
The reason being that sometimes they would have to be grown in the house.
As one does with houseplants.