Fielding Questions: Christmas cactus conundrum, snow-damaged hedge, African violet cuttings
This week, gardening columnist Don Kinzler fields questions about a Christmas cactus that only bloomed on one side, how to repair a snow-damaged cotoneaster, and more.
Q: I received a Christmas cactus in 2021, and this year it bloomed all the way around the plant at Thanksgiving time. Now, as you can see in the picture, it’s blooming again, but only on the front third. It does get some afternoon sun. Should I move it completely out of the sun? Should I turn the planter periodically? Any advice would be appreciated. – Sandy F.
A: Although many such cacti are referred to as a Christmas cactus, there are three distinct species of these holiday cacti: Thanksgiving cactus, Christmas cactus, and the rarer Easter cactus. Your plant in the photo is a Thanksgiving cactus, identifiable by the visible prongs at the joints of each stem pad. A Christmas cactus has rounded, smooth stem pads, without the prongs at joints.
Both Christmas and Thanksgiving cacti are triggered into flower bud formation by an interplay of night temperature and daylength. If nighttime temperatures in the room stay above 68 to 70 degrees F., these plants aren’t likely to bloom.
If too much light is received at night, either from within the room, or from a streetlight coming through the window, bloom isn’t likely. Holiday cacti can rebloom, whenever temperature and light conditions trigger more flower buds.
To coax a Christmas or Thanksgiving cactus to bloom, select a growing location near a cool window having a microclimate that will drop to around 60 degrees F. at night, and that’s also totally dark for at least 8 hours each night. Some rooms are naturally well-suited, which is why some holiday cacti bloom for their owners without fail, and with no extra coaxing.
Holiday cacti will sometimes form flower buds on only one portion of the plant if that part received the necessary temperature or light trigger. Only a few degrees variance from one side of the plant to the other can make all the difference. Rotating the plant every few days is a good idea.
Q: When should a cotoneaster hedge be trimmed back due to heavy snow damage? How close to the ground should it be trimmed? – Jerry A.
A: This has been one of the more damaging winters to shrubs, as the early wet, heavy snow froze into an icepack that’s been weighing down branches ever since early December. Branches become extremely brittle in frigid weather and removing snow and ice isn’t easy.
If branches don’t snap under the weight, they’ll often return to normal shape in spring, or at least somewhat. Branches that have snapped will need pruning.
Snow damage on deciduous (leafy) shrubs and hedges is relatively easy to repair, because nearly all such shrubs can be pruned back severely to four-to-six inches above ground level and they rebound energetically from the base.
To repair your cotoneaster hedge, prune all branches back to about four inches above ground level in early April while it’s still dormant, before any new growth starts. Apart from repairing snow or rabbit injury, this is a great way to rejuvenate a cotoneaster hedge that’s become leggy and sparse at the base.
Q: I attended a recent webinar you presented about starting houseplants from cuttings. When you discussed starting African violets from cuttings, what was the material you started them in? – Charlene S.
A: African Violets root quite easily from just a leaf and about an inch of the leaf stem. Several materials can be used, but for rooting cuttings, vermiculite is a favorite for mine. Vermiculite looks like little flakes of gold, and it can be purchased at garden centers.
You can root African violets in a Styrofoam cup of vermiculite (poke holes in bottom of cup first.) Insert the African violet stem so the bottom is just barely covered with vermiculite. You can also dip the stem in rooting powder before inserting into the vermiculite.
Next place the cup in a plastic bag to create a humid greenhouse-like effect around the cutting. Allow a little air into the plastic bag by poking holes or leaving a corner of the top open. Place in bright light, but not direct sunshine. Small plantlets will appear at the base of the leaf in one-to-two months.
If you have a gardening or lawn care question, email Don Kinzler, NDSU Extension-Cass County, at email@example.com . Questions with broad appeal may be published, so please include your name, city and state for appropriate advice.