Q: Can you identify this tree in our home? Eight years ago, a friend was going to Florida for the winter and asked if I’d babysit her 3-foot tree. When she returned, she said I could just keep it. It’s done well in its south window, and is now 8 feet tall, but I don't know what to do with it.
It has new growth on the top every year, so should I prune the top? Would it survive outside? There are new sprouts at the base, but I really hate to kill the large tree. Any suggestions? — Connie K.
A: The evergreen is a Norfolk Island pine, which we also discussed as a Christmas tree alternative in a recent column. In its native tropics, they can reach 200 feet high, which is why given sufficient light indoors as a houseplant, they can easily surpass ceiling height.
Norfolk pines aren’t winter-hardy outdoors in our region, and are quickly killed by freezing temperatures, so planting outdoors isn’t an option. To maintain at its current height, you can prune out the top growing point once a year.
A more drastic approach would be to cut the main tree trunk down, and let the sprouts that are visible at the base become dominant.
Q: I have found, as you have suggested, that 10-10-10 granular fertilizer is great for gardens. Do you have a suggestion as to how many teaspoons to put into a gallon of water for houseplants, where using the granular form doesn’t work well? — Monroe B.
A: I’m glad you’ve had success with 10-10-10 granular fertilizer, which is a great all-around product for fertilizing vegetables, fruit, shrubs and flowers. The granular formula is meant to be used in the dry form, and the granules don't seem to dissolve uniformly enough in water to be used in solution form on houseplants. The labels of common granular fertilizer brands rarely include a rate for potted plants.
Other fertilizer types, referred to as water-soluble, truly dissolve in water, such as the Miracle-Gro brand, forming a liquid solution that’s convenient and effective in fertilizing houseplants.
Another fertilizer type that is effective for all potted plants are slow-release types, which are composed of beadlike particles formulated to slowly dissolve in the soil, releasing nutrients over time. Osmocote is a brand commonly found at garden centers.
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Q: I have a caragana hedge along the back of my property that I’ve been maintaining at a height of 8 feet. To make this easier, I’d like to cut it back to 6 feet. Should I just cut off 2 feet and continue trimming at the 6-foot level, or should I cut it down further, maybe to 5 feet, before letting it grow back to 6 feet? Would that make the top be thicker? — Steve J.
A: Caragana was commonly used as a hedge around farmsteads and homes in the early 1900s. I’ve always liked caragana as a tough, winter-hardy hedge, and my grandparents had such a hedge around their farmyard between Alice and Fingal, N.D. Most of it was maintained about 4 feet high, but some was allowed to grow to its natural height of around 12 to 15 feet.
Every so often, we would prune the hedge all the way back to about 6 inches above ground level and let it grow back full and thick, because it tended to get leggy and open at the base. You might consider such a rejuvenation, if your caragana hedge ever becomes bare and unsightly at the base.
To reduce your hedge from 8 feet down to an eventual 6, you might consider cutting it down to 4 feet next spring before it leafs out, which could promote thicker branching, and it’ll soon rebound to 6 feet. Such shrubs tend to proliferate at the point at which you prune, so depending where you would like better branching, prune down to that level.
If you want the hedge well-branched at the base, rejuvenate down to the 6-inch level, as mentioned before.
If you have a gardening or lawn care question, email Don Kinzler, NDSU Extension-Cass County, at firstname.lastname@example.org. Questions with broad appeal may be published, so please include your name, city and state for appropriate advice.