One good reason to grow rosemary is that otherwise you can't find it at markets, not in big branches to use for Christmas.
Juniper, box, holly, ivy, bay, mistletoe -- these are all great for Christmas, though I guess the day is fast approaching in which plastic replicas will serve all but the very rich.
Some -- indeed, all -- the traditional greens have a good bit of lore attached to them, but mainly they are traditional greens because there wasn't anything else commonly available in the past, except yew, and yew was sacred to Palm Sunday in place of palms (which never grew in England until recent years when gardeners started trying them along the western and southern coasts).
I would not hesitate, myself, to use any greens I had: andromedas, pine, spruce, mahonia or anything else.
Every year I take either a mallet or (in years the mallet cannot be found, which about every other year) a hammer, and smash the bottom two inches of the branches. It is said this helps them absorb water and causes the greens to last longer. I doubt it, but I do it.
The rosemary problem has never been solved, with me -- nor the bay, either. Often we have had rosemary growing in the garden, in the final stages of decrepitude, but have never had enough to cut branches for the house. s
One of the most beautiful greens is rue (Ruta graveolens), which is almost all blue, and one year the garden was full of it; but it seemed wrong, somehow, to cut rue for Christmas, so we didn't. But each man to his own inhibitions.
Some people will not bring ivy into the house for Christmas, despite its long association with Christmas. Perhaps they object to it because it was sacred to Dionysus, the god of wine and the theater and other heathenish things. But that never seemed to me very much of a legitimate objection. Christmas itself, after all, is timed to replace pagan festivals; but if ivy doesn't seem quite right, then there's nobody forcing you to use it.
Cedar is not a traditional green -- I mean the true cedars (Cedrus libani, deodars, atlantica) from Lebanon, the Himalayas, the Atlas Mountains -- though they are beautiful and (if you have an old tree in the garden) available by the ton. Furthermore, Solomon's temple was built of the cedar of Lebanon, which Solomon bought from Hiram, the king of Tyre and was endlessly proud of.
At the Nativity itself, cedar (from Lebanon) was much more likely in the neighborhood than mistletoe or holly.
Rosemary, by the way, was sometimes reckoned to be the wood of which the Cross was made; hence the tradition that after 33 years of age, the rosemary never grows any taller. With us, it usually freezes in the winter its first or second or third year, so it is difficult to test this. And everywhere it tends to sprawl and die out here and there. The obvious fact that nowadays rosemary wood is too slight to construct anything at all is no argument, probably, against its constructional uses in the past.Especially its uses in legend.
All Christmas greens used to come down on Jan. 7, the feast day that marks the appearance of the kings from the East with their gifts. American housewives tend to lose patience with drying greens, however, long before then, and undoubtedly most American houses now bring the greens down on New Year's Day.
It's a question, I imagine, how traditional you are and what tradition you got used to as a kid, as well as how much you heat your house. In our house, I believe the greens could stay up until May, since there is no furnace heat to speak of that might dry them out, though the smoke from the fireplace (every since I foolishly had it cleaned out a couple of years ago by a chimney-sweep firm) would probably pickle them, as it does us.
All the greens are more or less magical, and bad luck follows leaving them up after Jan. 7. For every berry you miss, you will see one goblin, it is reliably reported by the poet Herrick, who was quite sound on traditional lore.
My neighbor, the Widow Barnes, assures me holly berries are poisonous to cats. She will not have it about, because of Napoleon. I am almost sure Luke used to eat holly berries, along with everything else, but then he was a hound and perhaps holly does not poison hounds.
Mistletoe is widely believed to be poisonous and so are poinsettias. So is the gasoline in the car and the brass polish and much else that is about the house; but in case creatures at your dwelling are much given to eating everything, then I'd be careful of all plants and assume all of them are poisonous. I have myself eaten mistletoe berries on several occasions, which shows not only that a few of them will not kill you (or didn't kill me) but also that kids will try eating almost anything.
Not everybody is Christian, of course, but I see no reason they should not enjoy fresh branches of green in the house at this season. Most Christians, after all, are not very Christian either.
Once I tried out a wreath of ivy in my hair -- quite privately, of course -- such as you see in various classical sculptures from pre-Christian times, and I thought it looked well. There are two theories about ivy, that it keeps people from getting drunk or that its scent increases the drunkeness. I merely tried out the garland and know nothing about the rest. But some pagan might wish to experiment.I have heard that ivy berries are poisonous, too. Just so the ivy will not feel left out, possibly.
Almost always we bring in yew branches for Christmas, traditional or not. Let me warn you that one year I cut a whole jeep-load of yew branches for the parish church in Tennessee to use outdoors on the pavement around the main door, and I regretted this because several rather large yews died from this severe harvest. I did not know, then, that while yew will take butchering better than almost any other plant, still there are limits; and the hybrid yews (Taxus intermedia), which is what we largely grow, will not stand for sudden severe pruning back to the trunk. Never prune away more than a third of the tree at once, I have since been instructed.
I imagine few readers had really intended to go out and saw all the branches off their yew trees for Christmas. But then (as one learns at my age) there really is no telling.