This is the flip side of the list I posted on May 27, which was about easy plants I recommended for beginning growers of houseplants. These are the ones that are fairly easy to get (usually a little less common than the easy ones; it depends where you shop), but are not good prospects for growing year-round indoors.
There are a number of reasons why this could be the case. Some of the plants on the list are very prone to bug problems. Some of them are easy enough to keep alive, but are unlikely to ever again look as good as they do when you first see them in the store. Some have completely unreasonable care requirements, or are slow to recover from damage and consequently just sit there looking like crap forever if you forget to water once. That sort of thing.
I either know, or have at least heard of, people who have been successful with each of these plants. I have no doubt that there will be people reading the list who will say but I have a [name of plant] and it was the first one I ever bought and it's been awesome for me for fifteen years; I think you're nuts. And to those people, I say congratulations. (Also I say that whether or not I'm nuts is not the issue.) I know of many more people, however, including some people with a lot of indoor plant experience, who have tried some of these and failed multiple times.
The unfortunate thing is that these are still being sold, a lot, because they're really damned attractive. The stores don't actually care what happens to your plant once you purchase it, and in fact would probably rather you killed them, everything else being equal (people with dead plants are people who will buy replacements), so they'll keep getting them in. But give some easier stuff a try before handing over your money for these, is basically what I'm saying.
Alocasia amazonica 'Polly.' (African mask plant)
Why you would want one: they have big, dramatic leaves with striking shape and coloration.
Why you shouldn't get it: spider mites love them, they're fussy about humidity and temperature, and occasionally they will decide to go dormant, which if you don't know that they do this will make you think you killed it.
What to buy instead: Anthurium andraeanum (some cultivars have similar leaf size and shape, plus flowers), Ficus elastica 'Burgundy' (similar leaf color, size, and texture), Philodendron 'Congo Red' or 'Imperial Red' (similar leaf size and color), Syngonium wendlandii (vining plant with velvety, dark green, arrowhead-shaped leaves and a contrasting lighter center).
If you've already bought one: watch carefully for spider mites (they will show up as light webbing on the underside of the leaves and a dusty, tan, washed-out look on the tops of the leaves). Keep humidity and temperature high (not below 60F/16C). Provide good light (filtered sun or very bright indirect or artificial light). Hope for the best.
Begonia rex-cultorum 'Harmony's Red Robin' (shown) and other Begonia rex-cultorum cvv. (rex begonia)
Why you would want one: iridescent-metallic, multicolored leaves in green, gray, red, black, pink, purple, or silver, on a low, trailing plant.
Why you shouldn't get it: unreasonable environmental requirements, plus prone to mildew and other fungal diseases, unforgiving of lapses in care.
What to buy instead: Saxifraga stolonifera is a very easy, low-growing plant with silver-veined green leaves which are red underneath. Tradescantia zebrina is a trailing plant which usually has purple leaves striped in silver. Pilea involucrata 'Norfolk' trails, and has red, brown, gray, and silver leaves depending on the amount of light it is receiving; it's not a particularly good beginner plant, but I'd consider it an improvement on rex Begonias. Some of the cane Begonias, particularly the angel-wing or trout-wing types, may be slightly easier to get along with than the rexes, and have coloration which is similar, though their habit is very different. Some rhizomatous Begonias (Don suggests 'River Nile' in the comments) are also less fussy, and the patterns are frequently just as interesting even if the color range is narrower.
If you've already bought one: provide bright indirect light or filtered sun to maintain color. Keep humidity high around the plant, but try to avoid splashing water directly on the leaves. Do not allow the plant to dry out completely.
Calathea roseo-picta 'Medallion' (shown?) and other Calathea spp. (peacock plant, rattlesnake plant, zebra plant, pin-stripe plant, etc.)
Why you would want one: large oval leaves with delicate, fancy-schmancy streaks and blotches of color.
Why you shouldn't get it: drought-intolerant, sensitive to fluoridated water, prone to spider mites, unreasonable expectations for humidity.
What to buy instead: some Aglaonema and Dieffenbachia cvv. have similarly intricate color patterns and oval leaves, if not an equally broad color palette. Peperomia obtusifolia has some cultivars with feathery green-and-yellow variegation (for example 'Golden Gate'), and though it's a much smaller plant, it's also much easier. Variegated Epipremnum aureum cultivars like 'Marble Queen' have fairly intricate, swirly patterns, though the colors tend to disappear if the plant is grown in low light.
If you've already bought one: as for Alocasia, above.
Dionaea muscipula. (venus flytrap)
Why you would want one: dude! They move, and kill insects and shit!
Why you shouldn't get it: need special water because they're mineral-sensitive, very strong light year-round, and inhumanly cool temperatures during winter (when they go dormant). Plus they rot at the drop of a hat.
What to buy instead: not many good options. The sensitive plant, Mimosa pudica, also moves in response to touch and is perhaps a little more manageable, though it also needs very bright light and is not, in my opinion, a very pretty plant most of the time. I've heard nice things from certain quarters about Drosera (sundews), Pinguiculas (butterworts), and Nepenthes (pitcher plants), but my experience with Nepenthes is that they're not easy at all, and I'd be surprised if the others were either. I would recommend that a beginner either wait for a long time to attempt carnivorous plants in general, or else commit to growing nothing but carnivorous plants, because their needs are very different from the plants people normally keep indoors, and very little of your experience with one group will transfer to the other.
If you've already bought one: they need lots of light (full sun), distilled or reverse-osmosis water, and a winter dormancy; read the Dionaea muscipula profile for more specific information. You might also consider getting a terrarium for it.
Euphorbia pulcherrima. (poinsettia)
Why you would want one: 'cause they're so fucking Christmasy and festive.
Why you shouldn't get it: they're just very badly-suited for indoor cultivation all around. They need tons of light, even during the winter when you're least likely to have lots of light; they need a lot of warmth; they're a pain to rebloom; they're usually potted in crappy potting mix because the growers don't expect them to survive past New Year's so there's no point springing for the good potting mix; they're usually artificially dwarfed using hormones, so even if you did manage to keep it until the next year, you'd have a leggy monstrosity; they tend to be stressed from being forced to grow fast and bloom fast; if you're in a cold climate, they've probably been shipped in cold and are stressed from that when you see them; they're prone to fungus, whitefly, and everything else; the lower leaves fall off at the drop of a hat, even if it's the next-door neighbor's hat; they bring untold misery and despair to garden center and greenhouse workers the world over; and I say not to.
What to buy instead: oh my god anything. An. Y. Thing. Norfolk Island pines (Araucaria heterophylla) can be very nice long-term plants if you have a bright, cool spot for one. Schlumbergera cvv. ("Christmas cactus") are very easy, though plants purchased late are prone to drop flower buds once you get them home, so try to buy them out of season or else as early as you can. Those are probably the two I'd most recommend. But if you don't like those, English ivy (Hedera helix) is common in stores around Christmas: it's a terrible, terrible idea to start your houseplant career with Hedera, but better that than poinsettias. Forced bulbs like Hippeastrum ("amaryllis") can be saved and made into long-term, reblooming plants. Even Cyclamen persicum or Kalanchoe blossfeldiana, absolutely anything at all, just not a poinsettia.
If you've already bought one: enjoy it while it lasts.
Gardenia jasminoides. (gardenia)
Why you would want one: the flowers smell amazing.
Why you shouldn't get it: they have unreasonable expectations.
What to buy instead: there are no great Gardenia substitutes, because nothing else smells like a Gardenia. But Hoya lacunosa flowers are pleasant, and the plant is easy to grow. Quite a few of the other Hoyas have pleasant-smelling flowers, too, though ease of care and ease of flowering vary from one species to the next. Murraya paniculata is considerably easier than Gardenia though not easy, and blooms readily year-round if given enough light and water. Finally, Callisia fragrans, which looks and smells nothing like Gardenia, is still relatively easy to bring into bloom, and the blooms smell good enough. All three of the above substitutes also have going for them that they'll continue to bloom for a good long while, once they've started, if care is consistent.
If you've already bought one: Gardenias like cool nights for setting buds, so aim for low temperatures in the 50s F (10-15C). Do anything you can to keep the plant out of hot, dry air, as well, as this will stress the plant and encourage spider mites. Don't let plants dry out completely, either. Plants will also usually benefit from spending the summer outdoors, if you have a semi-protected spot you can keep the plant in where it won't sit in the sun cooking to death. See also the Gardenia jasminoides profile.
Juniperus sp. bonsai, other bonsai (juniper, fukien tea, elm, Japanese maple, box, etc.)
Why you would want one: they look like adorable little trees, they're Asian-feeling, you have action figures that would look perfect sitting next to a miniature tree.
Why you shouldn't get it: Juniperus in particular needs much cooler winter temperatures than most houseplants, and won't survive a winter indoors with central heating. Other types of bonsai tend to be extremely touchy about heat and drought. There's also a lot of precise work involved in keeping the plant miniaturized: they want to be full-sized trees, and are only miniature because they're being deprived of root space and fertilizer, and keeping them in line is something of a job.
What to buy instead: some varieties of Ficus, especially F. benjamina 'Too Little' and F. microcarpa, are used as bonsai specimens, but are more resilient and accommodating than most species used as bonsai. 'Too Little' is genetically inclined to grow tiny, bonsai-scale leaves, even when it's not being treated like a bonsai, and consequently is easier to maintain as a miniature tree. Polyscias fruticosa and Crassula ovata maintain a treelike form as they grow, branching spontaneously and forming woody trunks (Crassula ovata is occasionally a legitimate bonsai subject.). Polyscias fruticosa also tends to develop gnarled, bonsai-like forms over time. Araucaria heterophylla doesn't do a very good pine impression, and eventually gets very large, but if you're looking for a houseplant conifer, it may be as close as you're going to get, as a beginner.
If you've already bought one: depends on the species. I recommend Googling for your particular species ("common bonsai subjects," maybe?), or else (if it was sold without an ID tag, as will usually be the case) locating a dedicated bonsai forum of some kind, where you can get advice specific to your plant.
Lithops spp. (living stones)
Why you would want one: the weirdness of a plant pretending to be a couple pebbles, or the novelty of a plant with windows in its leaves, or just the all-around freakyness of the thing.
Why you shouldn't get it: watering is tricky, and they demand a lot of light.
What to buy instead: Astrophytum species of cacti, especially A. myriostigma, sort of resemble oddly symmetrical rocks. They're a little touchy about overwatering, too, but not to the same degree. Senecio rowleyanus resembles green beads on a string, and portions of the leaves are translucent. Quite a few Haworthia species, though not all of them, have "windows" at the tips of their leaves, though the resemblance to pebbles is debatable. Pachyphytum spp. look like small piles of pebbles, to varying degrees.
If you've already bought one: give it as much light as you possibly can, and give it water only 1) when it looks like it's shriveling up, and 2) in late August. Otherwise, not even a drop, you hear me? When you do water, don't feel compelled to drench the soil, either. Less is definitely more in this case.
Ravenea rivularis. (majesty palm)
Why you would want one: you're looking for a palm, and it's big and cheap. (The one in the photo is an unusually small specimen.)
Why you shouldn't get it: they're all but impossible to grow indoors in a long-term way. The reason it's so big and cheap is that in Florida or wherever they're being produced, they grow very, very fast, so there's less time invested in a majesty palm than in most of the others, which means less fertilizer, less water, less pesticide, etc. The down side is that although they grow very well in an outdoor tropical climate, indoors they completely suck balls.
What to buy instead: kentia palms, Howea forsteriana, tend to be outrageously priced when one even manages to find one, but people rave about them being incredibly good plants. I've never had the pleasure of growing one, though, so don't know whether I agree. WCW used to talk up the spindle palm, Hyophorbe verschaffeltii, as being a very good indoor palm, but I've never tried that either, and again, they tend to be pricey. I'm personally partial to lady palms, Rhapis excelsa, though they lack the arching, finely-divided fronds of Ravenea and are slow growers and therefore expensive. If it's just the general V-shape you're into, Dracaena fragrans 'Massangeana' is widely available, cheap, and has a certain palminess to it, as do the various cultivars of Dracaena deremensis ('Warneckei,' 'Lemon-Lime,' 'Janet Craig,' 'Limelight,' 'Art,' and so forth), Ficus maclellandii, and Yucca guatemalensis. Strelitzia nicolai, the white bird of paradise, does a decent job of signifying tropical, and is usually not that expensive, though they're very big and need a lot of light to do well.
If you've already bought one: don't get too attached, monitor for spider mites, and give it as much light, heat, and humidity as you can manage. Ravenea would probably also benefit from spending summers outside in a semi-shady spot, though they're extremely thirsty, so make sure to keep it watered.
Selaginella kraussiana cv. (shown) and other Selaginella spp. (spikemoss, clubmoss)
Why you would want one: delicate, finely-divided foliage, sometimes with a deep red underside (S. erythropus) or iridescent blue sheen (S. uncinata).
Why you shouldn't get it: they're unforgiving of low humidity, over- and underwatering.
What to buy instead: there aren't a lot of alternatives for this one either. I like some of the Davallias (rabbit's-foot ferns) for delicate, finely-divided foliage, and at least one of mine (D. tyermanii) has a slight blue tinge to it. Crassula muscosa has a similar texture and is easier care when properly established, though a lot of the plants sold seem to be sold before they've rooted completely, which makes them somewhat difficult. Pilea depressa lacks the color and is not as fine-textured, but it's still in that same small-leaved creeping category.
If you've already bought one: get a terrarium and plant Selaginella in it. You'll both be much happier.
Don't start with these either:
Adiantum spp. (maidenhair fern)
Asplenium nidus / antiquum (bird's-nest fern)
Caladium spp. (angel wings)
Citrus / Fortunella / etc. (citrus, lemon, orange, lime, kumquat)
Codiaeum variegatum (croton)
Cyclamen persicum (florists' cyclamen)
Fenestraria rhopalophylla (baby toes)
Hedera helix (English ivy)
Hibiscus rosa-sinensis (hibiscus)
Jasminum sambac (jasmine)
Kalanchoe blossfeldiana (flaming Katy, kalanchoe)
Maranta leuconeura cvv. (prayer plant, rabbit tracks)
Nepenthes spp. (pitcher plant)
Oxalis triangularis ("shamrock")
Rhododendron cvv. (azalea)
Rosmarinus officinalis (rosemary)
Soleirolia soleirolii (baby tears)
Streptocarpus cvv. (cape primrose)
Stromanthe sanguinea cvv.
tree ferns (Blechnum, Cyathea, Dicksonia, Cibotium)