Merry Christmas Eve! Remember to keep cut trees well-watered. Slide a stick down into the reservoir and add water if it’s a little dry.
If you received a rosemary Christmas tree as a gift, move it into a larger pot ASAP. These cute little trees are always rootbound and moving them into a bigger pot with more soil makes them much easier to keep alive.
Keep poinsettias warm and well watered.
Once the flowers on your holiday amaryllis are open, move the plant into a cool spot out of direct light to prolong the bloom time. Once the flowers have faded, move the green plant back into bright light and give it a gentle feeding to begin preparing it for a fresh run of blooms next season.
And you know those cute little paperwhite bulbs you grow in rocks and water? (They’re popular gifts this time of year.) You can keep your paperwhite stalks nice and tidy instead of tall and lanky by watering them when they’re still small with nine parts water to one part vodka or gin. Really! It dwarfs the plant naturally, doesn’t impact the flowers one bit, and makes for a much better show.
Old Christmas trees are for the birds
What plans do you have for your cut tree after Christmas? Many neighborhoods have recycling programs, but you can also recycle that tree yourself.
If you followed my advice from back in the fall and have pansies growing outside, prune the branches off your tree after the holidays are over and keep those cut branches at the ready to cover the plants if ice or heavy snow is forecast; the springy boughs offer perfect protection against a winter crush.
Or take the tree out back and hang suet feeders where ornaments once were. The big branches make it easy for winter birds to feed in safety and comfort, and suet feeders attract chickadees, nuthatches, wrens, woodpeckers and other carnivorous birds, all of whom will hang around and eat your garden pests for you in the summer. You can smear some peanut butter on the branches as well. The birds love it.
Houseplant pests? Be careful with ‘soapy water’
Susan in D.C. has a very common question for this time of year.
She writes: “We have fruit flies in our office. Some folks have plants and some don’t, but all the offices have fruit flies. Building management suggested spraying the plants with soapy water and some plants have been sprayed. But since the spraying, the fruit flies are worse. Any suggestions?”
Yes, my first one is to be very careful with “soapy water.” Professionally made insecticidal soap is great at smothering pest insects, but home-made soap sprays often act as herbicides. And be aware that insecticidal soaps and horticultural oils are contact pesticides. They must soak the pest to be effective. Just spraying the plant won’t stop the pests.
Fruit flies? Fungus gnats? Name that indoor pest
In our last thrilling episode, Susan in D.C. asked for help with what she called “fruit flies” in her office. “Some folks have plants,” she explained, “and some don’t, but all the offices have fruit flies.”
Well, Susan, it’s not uncommon for workplaces to have the occasional fruit fly infestation, especially when people eat at their desks or bring fresh fruit into the office. Luckily, it’s easy to break the cycle of infestation. Leave out little saucers of vinegar on each desk; the pests will gleefully drown themselves in it.
Then make sure that no food is left out on desks or even tossed into trash cans for a solid week. Have your co-workers seal all leftovers in plastic bags before tossing them in the trash. Any remaining flies will vanish by the end of the week.
But your pests could also be fungus gnats, which look similar but breed in houseplant soil. If that’s the case, have the plant owners cut way back on their watering and cover the soil in the top of each pot with a half inch layer of sand to prevent the adults from laying new eggs in the soil.
If the infestation proves hard to control, get a BTI soil drench (like this product from Gardens Alive). It’s a totally non-toxic larvacide that kills the nasty little worm-like baby gnats while they’re still down in the houseplant soil.
Tough time of year to transplant a tree
Kirk in Warrenton writes: “I’m a gardening novice with a question about transplanting a young pine tree that’s about three to five feet tall. Will the tree survive if some roots are cut or broken? And how much water should it get and for how long at this time of year?”
Oof! I strongly suggest you wait until spring, Kirk. It’s really hard to get a tree out of rock hard frozen soil, or to even dig the new hole at this time of year. When the soil softens, get a bunch of guys together and dig out a wide area around the base until you can heave it out of the ground, root ball and all. The more intact the root system, the better it will survive the move. (And it will take three or four guys to move the thing if you do this right.)
Plant it high in its new hole, with the root flare showing (don’t make it look like a lollipop). Fill the hole back up with the soil you removed to dig the hole. Don’t amend the soil in the planting hole with anything. Mulch the tree with an inch of compost, starting six inches out from the trunk and going out two to three feet all around. No mounding, no touching the trunk, and no wood or bark mulch.)
Then let a hose drip very slowly at the base for 24 hours. Afterwards, give it a similar deep slow watering for at least an hour twice a week if we don’t get rain-and keep the watering up until fall if rain is scarce.