What you need to know to care for holiday greenery

Virtually all the greenery we use to mark the holidays is an invention of modern times, though the sacred sentiments they express of goodwill and good cheer are deep-rooted and timeless.

Besides poinsettias, there are many other organic, vegetative ornaments that make the season come alive. Just remember that if the holiday spirit is eternal, these plants decidedly are not.

Rosemary topiary

A rosemary topiary (Courtesy of Smith & Hawken)

In the language of the herbalist, rosemary is for remembrance, as in, “Do you remember last Christmas when it croaked before we opened the presents?”

Indoor rosemary trees and other topiary forms are alluring — cute, fragrant, festive — but they are not plants to grow old with. If you accept their fleeting nature, you may treasure your brief encounter.

There are ways to prolong the experience, but unless you have a bright, cool conservatory or an approximation of one, the rosemary tree is sort of doomed.

Field-grown in warm climates or raised in greenhouses, rosemary trees are too tender to go outside in Washington — they haven’t been acclimated in the way that garden-variety rosemary has — and yet the typical indoor room is ill-suited to their needs. It is too dark, too dry and too warm, though those conditions alone are not the rosemary’s biggest peril. When they start to look a bit peaky, our impulse is to water them, which hastens their demise.

If you want to give yours a fighting chance, take it out of the foil wrapper, place its plastic pot into a decorative cache pot, and keep the rosemary on the brightest, coolest windowsill you have. Typically, tables are too far inside a room to have sufficient light levels.

Water it only when you feel the top surface of the soil is dry: Grab the inner pot, run it under the tap and let it drain in the sink before returning it to its outer pot. If you keep the soil constantly moist, it will decline rapidly.

Mass-produced rosemary topiaries tend to be a little ragged and not entirely symmetrical. I fluff them up with my hand to bring out their scruffiness and then use scissors to give them a grooming.

If you are into rosemary topiary deconstruction, you can harvest some stems for culinary use. Rosemary farmers may use pesticides, which is something to consider, but so do apple, citrus, peach and strawberry growers. Wash it before use. Or before it dies.

Mass-produced rosemary topiaries tend to be a little ragged and not entirely symmetrical. I fluff them up with my hand to bring out their scruffiness and then use scissors to give them a grooming.

If you are into rosemary topiary deconstruction, you can harvest some stems for culinary use. Rosemary farmers may use pesticides, which is something to consider, but so do apple, citrus, peach and strawberry growers. Wash it before use. Or before it dies.

Greenery

Garland. (Len Spoden/For The Washington Post)

Evergreen wreaths, ropes and garlands come in many forms — fir, spruce, cedar, pine, boxwood, holly and magnolia, to name the most popular types. They are all perishable, and the challenge is to keep them fresh, which is linked to where you place them, how you condition them and the type you choose.

“It’s just so difficult to get it to last,” said Linda Roeckelein, who as head of the Alter Guild Of the National Cathedral is responsible for furnishing the cathedral’s Christmas greenery. This includes 10 56-inch wreaths on the pillars of the nave and various wreaths and ropes elsewhere in the cathedral.

Guild members typically install greenery at the beginning of Advent (this year Nov. 30) and then replace it with fresh material in mid-December. The big wreaths, of cones, fir and cedar, don’t go up until the week before Christmas.

Roeckelein likes to prolong greenery by making fresh cuts and keeping the branches in a bucket of water for a day before assembly. This is not an option, obviously, if you buy ready-made wreaths and garlands. Boxwood and holly tend to last longer than other material. Spraying greenery with a horticultural anti-desiccant will help. Roeckelein sometimes dips the material in a weak solution of floor polish to achieve the same effect.

Wreaths can be formed from a ring of saturated Oasis floral foam, she said, which will prolong the greenery’s life. The garland planned for the cathedral’s high altar will be a row of stems in moistened foam, arranged to look like one long piece. The effect could be replicated on a mantel

Southern magnolia leaves are good for a week or two but can be preserved with a long deep soak in a glycerin solution. The optimum treatment can take as long as six weeks — too late for this season — but an option for future Decembers. The treatment dulls the leaf color, but you can’t have everything.

Berries have a tendency to dry and drop before the greenery declines — there is no shame in using artificial berries, or even faux fruit. This leads to the vexed question of whether entirely artificial greenery passes the good-taste test. It comes down to the quality of it, I’d say. Some synthetic versions scream “hydrocarbon,” but others are entirely convincing, though you lose the piney fragrance of the real McCoy. You will know quality when you see it, which may make ordering online a problem.

Mistletoe

A bunch of mistletoe (Viscum album). (Alistair Scott)

Mistletoe is an evergreen tree parasite that is toxic, especially its white berries, but it had been ascribed magical powers long before the Victorians reinvented it as a Christmas ornament. But a plant that at times was said to open the doors to the underworld and, later, bring smooching couples together at Yuletide seems to have become a generational dinosaur. Or so I thought, until I found a music video of Justin Bieber with a Christmas song named “Mistletoe.” The song lasts an excruciating 3 minutes and 10 seconds and is capped with Bieber and his lucky date kissing under what appears to be a sprig of boxwood, but hey ho.

Amaryllis and paperwhites

A paperwhite. (BIGSTOCK )

I’m a fan of both of these indoor bulbs for the holidays, though a lot of people dislike the pungent fragrance of the paperwhite narcissi.

The problem with these bulbs is that they take several weeks to grow and bloom, and unless you bought them already forced and in bud, or started them when they first hit the market earlier in the fall, you’re not going to have blooms for Christmas. (A cyclamen will fill that floral void if you’ve missed the amaryllis boat.)

A lot of gardeners enjoy watching them grow and can wait for the flowers to appear when they are ready. That may suffice because the prospect of amaryllis and paperwhite blooms in January and February makes the winter more bearable.

Another challenge is their tendency to stretch and flop. Any staking should be done when the growth is young, so it can be trained rather than trussed. Paperwhites are more recalcitrant, and it helps to plant the bulbs deeply and to have high-sided containers. The more light you can give them, the less they will stretch. A little rubbing alcohol in the water will also stunt growth. The cooler their environment, the longer the display.