Q: I kept last year's Christmas poinsettias alive and well this summer. They are big and very beautiful, but very, very green! Incidentally, they were not a true red poinsettia; they were more of a pink color. What do I do now? I think they have to get some nights and days of darkness.
A: Congratulations! You are now a poinsettia grower. You've taken excellent care of your plants, and now, with a little more work, they will reward you with blooms. But don't expect them to be as large and glorious as plants you bought last year. They will be smaller but just as beautiful, more like the wild poinsettias from Mexico.
Poinsettias are light-sensitive plants that time their blooming to the hours of daylight and darkness. If you interrupt the pattern, the plants may still bloom, but on their own time — maybe for Valentine's Day or Easter! You must now be in charge of timing their light accurately, and you must start the dark-light process now for blooms in mid-December.
Plants should be inside now and thriving on a warm, sunny windowsill. Treat them as any other houseplant — keep them watered, watch for bugs, especially mealy bugs, and fertilize with your leftover tomato fertilizer to promote buds. Now comes the hard part: Poinsettias need to be put in total darkness for 12 hours out of every 24 hours on a regular schedule for the next eight weeks. No cheating or peeking!
Depending on the number and size of the plants — and your stamina — you can put them in a closet or a dark room, or you can cover them with an inverted sturdy box or a lightweight sheet. Each day, you must return the plant to the sunny windowsill and water and feed as usual.
Surprise! One day in December, you will see color beginning to develop in the leaves, and you'll know you're on the way to a colorful Christmas. Your job is almost done. As soon as you see color, you can stop the total night darkness routine and return the plants to the sunny windowsill until next summer.
Q: An icky question for you: Friends step outside to smoke, and while there is a receptacle for their butts, they flick the ashes into an (unmulched) flower bed, and those ashes can pile up. Do I need to correct this? What's the effect of ashes in the soil (especially when it rains)? Do they make it more acidic or something?
A: My goodness! You do have the most interesting questions.
Cigarette ash is highly alkaline (with traces of potassium and calcium), so make corrections to the soil, but only after a soil test. You may have overestimated the amount of ash you are getting, but only you can guess how much your friends are smoking out there.
Could you persuade your guests to use an "outdoor ashtray"? A coffee can filled with sand or kitty litter would be more sanitary and, after all, you are giving them the privilege and allowing them to smoke on your premises. They should respect that.
There are also commercial outdoor cigarette receptacles. You see them outside the doors of many businesses, malls and offices, and they can be bought online.
You really should remove the dirty, filthy, old butts from the garden area. The filters are cellulose, not cotton, and will not rot in a lifetime. (Another reason for your guests to use a can/container for their butts: You wouldn't have to get your hands in the mess while cleaning out your garden each spring.)
But the No. 1 reason for not allowing the butts in the garden: Tobacco can carry tobacco mosaic, a deadly virus to plants.
Q: Last fall, I found seven to eight Oriental bittersweet plants growing in front of our shrubbery. I cut them down, but the vines are back. How can I get rid of them?
Also, I have wild roses growing near my shrubs. Is there any way to get rid of them, too? We do cut them down, but they keep growing back each year and have spread.
A: Isn't it strange? Weeds grow more easily than our desirable plants. You can see why bittersweet is on the list of invasive plants. It eventually will take over and strangle plants growing around it.
Getting rid of an unwanted plant that is growing right in the middle of a wanted plant is really difficult, but with persistence, it can be done.
You have a choice. Watch it closely and repeatedly cut it down, or kill it with a poison; both will take time.
Cutting is obviously what you have been doing. With both the rose and the bittersweet, constant cutting will rid the hedge of the weedy plants. And if the plant ever flowers, you must get every flower before it goes to seed. Cut and destroy the cuttings; do not compost.
Or you could carefully use a "plant poison" like Roundup. We do not condone the wholesale use of chemicals, but sometimes the careful and limited use is necessary.
Cut the unwanted plant as close to the ground as possible, then carefully paint the Roundup on the cut ends of the plant. By using a paintbrush instead of spraying, there will be far less chance of the poison drifting to your valuable plants. (This is also a way to get rid of poison ivy growing close to or in another plant.)
Both the constant cutting and the poison painting will have to be done repeatedly. Please wear gloves and dispose of your brushes carefully. Let me know what happens.
This week's dirt
Look all around the yard, under the picnic table, on back kitchen steps. The houseplants all enjoyed their summer outdoors, but now it's time to go inside for the winter.
How do you know? The night temperatures are flirting with the 50s now, and that's the minimum temperature for houseplants. Don't chance having all the benefits of summer negated by a cold night in October.
My, how some of them have grown! They will need new pots. Do repotting outside where it's easier and you can hose down any mess.
A stray branch or shoot? A snip or two won't hurt, but don't do a mass pruning at this time when plants are going to rest.
Have you had a frost yet? What does it mean to our plants when the weathermen begin talking about when we are going to have a freeze and what temperatures constitute death for most plants?
Light freeze: 29 to 32 degrees Fahrenheit — tender "juicy" plants, like impatiens are killed, with little destructive effect on other vegetation.
Moderate freeze: 25 to 28 degrees — widely destructive effect on most vegetation, with heavy damage to fruit blossoms and tender and semi-hardy plants.
Severe freeze: 24 degrees and colder — damage to most plants.
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North Shore Gardener by Barbara Barger of Beverly is a feature of Friday's Lifestyles section. Reach Barbara by e-mail at firstname.lastname@example.org or write to her c/o Salem News, 32 Dunham Road, Beverly, MA 01915. Previous North Shore Gardener columns can be found at www.nsgardener.com.