House plants!

Baby boomers remember the 1970's as the golden age of houseplants. Everyone grew (or killed) them. Dish gardens packed with little tropical plants --without drainage--were popular, lasting a little longer than flower arrangements. Creeping Charlie, Wandering Jew, Spider plants, Purple passion, and Piggyback plants were ubiquitous. Easy to grow from cuttings, but short-lived, these have faded from popularity.

The indoor environment is too dark, dry, and dusty for most plants. Keeping any plant confined to a container for months or years means learning to manage the water and nutrient requirements carefully.

Houseplants can be grouped by how 'sustainable' they are indoors.

Many plants with flowers or pretty foliage will live a few weeks or months indoors. Treat these like long-lived flower arrangements: most holiday plants, many of the pretty flowering plants you see at the grocery store, and some old friends such as Coleus.

The greenhouse production industry produces great, compact Poinsettias, Kalanchoe, mums, and other seasonal flowers. Keeping them attractive and getting them to bloom again requires special treatment, and your house isn't the place to do it. Some are fine outdoors, perhaps brought back in for the winter. Toss 'em and buy new ones, unless you enjoy a challenge.

Did you know that easterners grow oleander as a houseplant? Gardenias, citrus, jasmine, and other plants that we grow outdoors are also listed in houseplant charts. Why? They aren't hardy into the low 20's. But why bother here, when they can be grown outside more easily? Herbs and seasonal flowers should be considered temporary. Bonsai and cactus need bright light; most are better outdoors.

African violets, Anthuriums, and orchids top this list. African violets like everything moderate: light, moisture, temperature, regular light feeding. Anthuriums are pretty easy, holding their waxy, colorful blooms for many weeks without special attention.

Orchids have become hugely popular, and are so diverse they are worthy of a column all to themselves. General requirements are bright light, even moisture (water about once a week under most conditions--is that vague enough?), and regular feeding. Some types are easier, especially Phaelanopsis and Dendrobium.

Most of the popular and easy houseplants are trees or vines from the tropics or subtropics. Many grow in the forest understory, so low to moderate diffuse light is what they're accustomed to. These are the plants for novice gardeners and busy people! Look for types that don't get spider mites, and don't water too often.

Water management is the key to success!

Most houseplants need water every few days--more often in the summer, less often in the winter. But indoor conditions vary so much that I can't tell you how often will be appropriate in your house. A moisture meter can be very helpful--you just poke it in the soil and it tells you when the soil is nearly dry. Potting soils used by commercial growers are very high in peat moss, which becomes lightweight when dry. Just lifting the pot to check the weight can tell you when to water.

Be sure to water each time until some appears in the saucer, so the soil is thoroughly wet.

Note: water from a sodium-based water softener is toxic to plants.

Regular feeding is helpful. Well-known plant foods are mixed in water and used every time the plant is watered, or monthly. Osmocote is very simple: put a teaspoon or so on the soil every season, and a little bit of fertilizer is released each time the plant gets watered.

The potting soil it came in can be difficult to manage, and houseplants are root bound when you buy them. Repot to a larger container within a few weeks. Afterwards, repotting is best done every year or so, preferably in spring or summer because root regrowth is rapid and the risk of overwatering is reduced. Extra soil around the roots stays wet, and cold-and-wet can lead to rot. Some root pruning can be done to manage the plant's size. Garden centers and hardware stores may repot for you for a nominal fee.

Houseplants love regular showers! Spider mites like dusty leaves, so the spray nozzle in your sink, your shower, or a brief outdoor visit for a blast from the hose will help manage this common indoor pest. Mealybugs (white moldy looking insects that cling to the leaves and stems) and scale insects (brown bumps on the stems and undersides of the leaves) can be blasted off at the same time, or daubed with alcohol on a Qtip. A sponge with lightly soapy water can be used to wipe off pests.

Finally, consider the law of diminishing returns. Some foliage plants have a life span; take come cuttings to start over, and throw out the parent. Likewise, you can't keep repotting a tropical tree into ever-larger containers! So the time may come when you have to discard a plant, manage it as it gets increasingly rootbound--or remodel your house.

-----------------------------

The Philodendron family provides several of the easiest houseplants. Most can go pretty dry between waterings, and can stay rootbound in the same pot for years. Note: members of this family contain oxalate crystals. Toxicity varies.

• Aglaonema commutatum. Chinese evergreen. Marbled foliage on a small, elegant, tough plant.

• Dieffenbachia. Dumb cane. Many varieties are chronic hosts for spider mites, but Tropic Snow doesn't get them. Name refers to the fact that the juice will paralyze your focal chords.

• Epipremnum aureus. Golden Pothos. The easiest house plant of all! Great for college dorm rooms. Climbing or trailing vine. Philodendron cordatum (Heartleaf philodendron) and Nephthytis (Butterfly vine) are similar.

• Monstera deliciosa. Split-leaf philodendron. Leaves will be small under low light, huge in bright conditions. Species name refers to the edible fruit, which may be produced under ideal conditions.

• Spathiphyllum. Peace Lily. One of the few easy indoor plants which flowers, sporting white calla-lily blooms in summer.

• Codiaeum variegatum. Croton. Leaves are mottled with bright colors. Always get spider mites, so wash them regularly, but otherwise unfussy.

• Dracaenas. Graceful habit is kind of desert-like. Allow to go dry between waterings. Some are prone to spider mites.

• Ficus decora and F. lyrata. Two types of figs--Rubber plant and Fiddleleaf fig--have big, bold leaves. Easier to grow than their better known cousin, below. Eventually huge.

• Maranta, Calathea, and Ctenanthe. Prayer plant and its cousins. These have stripes or blotches on the leaves. Marantas close their leaves at night, as if in prayer--perhaps that they won't be overwatered. (The C in Ctenanthe is silent).

• Sansevieria species. Snake plant, Mother-in-law's tongue. Tough, desert-looking plants which can take very low light and can go weeks without water.

• Schefflera arboricola 'Hawaiian Elf'. . Dwarf umbrella tree. Cute shiny tropical leaves. The big Schefflera is very prone to mites; these are resistant. Will even survive most winters outdoors.

Considered fussy

These need careful watering, so learn their special requirements.

• Ficus benjamina. Weeping Chinese banyan Should be called Tree That Dies Indoors. What it really does is drop its leaves if you move it, repot it, over water it, or generally irritate it. Do best in the brightest light you have (direct sun through a window is fine) and are watered as seldom as possible. Will survive most winters outdoors.