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Tuesday, May 4, 2021

Dormancy Cycles in Sinningia

Sinningia leucotricha is a species that has a normal, leafless dormancy phase. They can be grown without this, particularly when young, but it is normal for them, and I think can result in better blooming cycles. However, if you are not used to keeping houseplants that are strongly seasonal in their growth, or even plants that produce a minimum of new foliage each year, this might be alarming to you. So let's discuss. 

 The first thing I need you to do is not panic. :)

So what does it look like?  First, the foliage starts looking tired.  It can even start looking like there is a nitrogen deficiency, like these plants here.

Sinningia leucotricha mature, aging foliage; semi dormant
Sinningia leucotricha seedlings with mature, aging foliage; semi dormant

How do you differentiate between nitrogen deficiency and dormancy? Well, I don't have a perfect answer for this, but largely I would consider "stage" or "season". In older plants that have been trained to seasonal growth through warm, damp summers and cool, dry winters, obviously they start to visibly shut down their foliage in the fall. But if you are an apartment dweller, and the plant gets only small seasonal changes, it is going to decide on its own when its time to take a nap. Here, you need to consider how long has the foliage been on the plant. Has the foliage been in place a while, and suddenly started looking trashy? If so, dormancy is likely. This may eventually align with the seasons, particularly on a windowsill, since the seasonal changes in light intensity and window draftiness will give the plant some signals.

As a side comment, I don't find the species to be a particularly heavy feeder, so by that token, nitrogen deficiency is automatically unlikely. Of course, it is also never quite impossible. Just make sure you feed it "sometimes."

If you see your plant doing this, perhaps slack off on the watering a little, letting it dry out more or for a little longer between watering, but wouldn't withhold completely.

Eventually, the plant may just get over itself and pop out some new growth, like the wee leaves you see starting here:

Sinningia leucotricha seedling with new apical growth

In this case, just continue on with normal care like nothing happened.

But the plant may fully shut down the foliage like you see here:

Leafless-dormant Sinningia leucotricha seedlings

It may even be crunchy-dry:

Crunchy Sinningia leucotricha foliage

I repeat: please do not panic.

At this point, we will similate a "dry winter". Ideally this means cooler temperatures - I usually keep plants around 55F in an unheated basement, but work with what you have. I've also just set plants aside on a cool tile floor away from the heat. You'll also dramatically reduce water at this stage. You can still water *a little*, on occasion, but bias toward bottom watering to avoid getting the crown of the tuber wet. Be patient. Accept that the plant needs a nap. As long as that tuber looks plump and undamaged, all is fine.

If the foliage seems to come off easily, take it off. Don't force it though, you don't want to chance damaging the crown by ripping the little stem off.

Remember to check on it periodically, see how it looks, see if there is any change. What you are watching for is this:

Fuzzy new Sinningia leucotricha growth!

Its wakingup! When you see this, you can put it back in high light if you've moved it off elsewhere while dormant, start increasing water, and maybe feed it at this stage. The plant is entering its spring/summer phase.

From here, you know pretty much what to expect. It will grow new foliage, sometimes one stalk, sometimes a few. It may flower soon, when the foliage is partially grown but not mature. During and after flowering the foliage will continue to expand until it reaches its full size for the season, at which point it will be a medium silver-green color. Then it turns to bulking up its tuber. The foliage may not change much, or at all from here to the end of the growing season, but the plant is busy doing important work below the soil surface to prepare for next winter.

You will likely find that each year, the foliage will increase in size or leaf count as the tuber increases in size. Enjoy watching the show each spring, knowing you've done a good job over the past year to help it prepare for the event.

For more photos and chit chat about this species in various stages of development, including a look at my oldest plant entering dormancy last fall and the beginnings of its show this spring, check out the instagram hashtag #pgcsinningialeucotricha.


Anonymous said...

Both concise yet wonderfully explanatory. Thank you for this👍🏼

Anonymous said...

Would there be any harm in watering once they go dormant. I have one that I don’t want to separate from the rest as they haven’t gone dormant yet, but I also don’t want to separate it and run the risk of forgetting to water it! Which would produce less catastrophic results: watering too often in dormancy or not watering often enough during dormancy?

Julia said...

Re: watering too little vs too much. I can't say that I've experimented extensively, but what I can say is this.
1. You can opt to not let them go fully dormant by continuing to water lightly, and keeping warm. The foliage in this case will hang on, but will look a bit tired. In the spring snap it off and continue watering as usual, and new growth will come in a few weeks. If its already starting some new fuzz, it'll go faster. When you do this, the tuber tends to get bigger faster, but they don't always bloom as well. But an advantage might be that its less scary for you.
2. Tubers that are of any size (meaning 1.5 inches or more) you can just... not water all winter. Now that I have thing things coming out of my ears, I do tend to do this with more of them for the sake of having less watering chores in the middle of winter. They do not care. Even without me watering them and keeping them around 50F, they're all starting to sprout. I just keep them near other cool growing plants so that I can see them easily, and know when they're waking up and I have to start paying attention to them.
To sum up, you have options. Now, if you were keeping the tuber cool and it did in fact shed its foliage, but you kept watering, I think that might be where the drama would happen. That said, I can't say for sure. Based on their behavior described above, I somewhat wonder if they wouldn't just carry on making new foliage early. They seem to be rather flexible on a number of points.

Anonymous said...

Thank you so much for taking the time to reply! Definitely makes sense, I think I’m just scared of dormancy turning into death. Just discovered all your sinningia content, it’s great:)