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How to choose poinsettias and Christmas trees

  • Author: Jeff Lowenfels
    | Alaska gardening
  • Updated: December 3, 2020
  • Published December 3, 2020

(Getty Images)

The holiday season is a gift for garden columnists. So many topics from which to choose for a change. And so many email questions. Some are classic holiday fare, of course, but there are some new ones as well.

I might as well start with this question: What kind of Christmas tree do I recommend for purchase? The reader obviously doesn’t realize I have a third-generation artificial tree in the garage, but this is an easy one to answer. Get whichever one pleases you. If anything has to do with personal preference, the kind of Christmas tree to buy does. Just make sure you buy from a reputable source.

Besides personal preference, there are some guidelines. Do you want something with very stiff branches that can hold heavy ornaments? Then your best bet is a noble fir. Frasier firs, on the other hand, have softer needles with a whitish-gray underside. Nordman firs have the very softest needles, and theirs don’t fall when they dry up. (Actually, needle drop means you are not giving your tree proper care, which includes lots of water). If you want to cut your own, you can do so in any national forest as long as you have a permit.

Next, even though loyal readers know I am not fond of them, I always get requests for advice on poinsettia care. (Man, that sounds like a self-setup!) I am amazed how many people simply cannot get through a holiday season without a few of these plants. They are, after all, the top-selling plant in the whole world. I must be a minority of one.

Simply put, poinsettias should get at least six hours of good light a day, but they don’t need direct sunlight. Temperature-wise, they like it between 60 and 65 degrees at night and 65 to 70 degrees during the day. Soil should be “cake moist,” which is not too wet or too dry.

It is the foil that pots are wrapped in that causes most of the problems. Remove it or poke a hole in it to allow water to drain so your plant does not have to sit in water, which they hate. Don’t let it accumulate in the saucer under the plant. Most important, poinsettias do not do well in drafts, hot or cold. These cause them to drop leaves.

You know the rest. You are buying poinsettias for their colorful bracts, not flowers, which are yellow and ideally shouldn’t be open when you purchase (look for pollen), as the bracts will last a bit longer. Don’t leave the plants in the car while you shop; once the temperature hits 50 degrees, leaves and even whole poinsettia plants die. Also, poinsettias are not poisonous, though they may be slightly toxic to pets.

Here is a new one: A reader asks if those little desiccant gel packs that accompany many gifts to keep them free of excess moisture have any use in gardening. They are usually just silica and oxygen. However, you do have to be careful. Some have additives in the form of cobalt chloride or methyl violet. Both change colors with the presence of moisture. Both are also toxic.

The one safe use for either kind is in keeping seeds at the right moisture level from season to season. Stick one or two of those packets in a jar along with the packs of seeds to keep and seal the jar up. I suppose you can also use them in soil or compost to add silica, not for attracting that much moisture.

Finally, holidays and winter in general result in lots of fireplace ash. What is the story with using that in the garden? Is it beneficial for soil or not?

As you can imagine, the answer to this question has a lot to do with the kind of wood used to make the ashes. Anything treated with chemicals is best left out of the gardens. This would include painted wood, pressure-treated wood and ashes from artificial logs. You should also avoid using ashes that used to be cardboard. It may have chemicals that can harm plants. While on the subject, don’t use charcoal residue or coal ashes either.

That said, wood ashes do contain lots of essential elements, especially calcium, magnesium and potassium, and usually can be added to soil and compost piles. However, the real impact of adding ashes to soil is it raises the pH, which should be around six to seven on the pH scale of one to 14. If your soil has too high a pH, then nutrients become chemically locked up and unavailable. So, test your soil’s pH before you add ashes. Also, realize it takes about six months to move your pH scale.

That said, garlic, chives, leeks, lettuces and asparagus usually do well with an addition of ashes. Potatoes, blueberries and strawberries are more acid loving, so don’t use ashes around them.

Jeff’s Alaska garden calendar:

Alaska Botanical Garden: Get tickets for the garden’s light display, take a virtual class to make a bird feeder or learn to watercolor paint mushrooms and more. Also, now more than ever: Join. What a holiday gift for the whole family! All at

Poinsettias and other plants: They are here. Most holiday plants last year round.

Lights: Really? After all this pleading and all the new darkness? Get some lights for your plants.