Dr. Matt Candeias talks about dormancy in all types of plants! From cacti and succulents to evergreens and tropical plants. Especially with climate change affecting the length of Spring and Fall, do your research to see if your plants require a dormancy period.
Publish Date: Apr 08, 2021
Uh, yeah. I mean, it's entirely dormancy is entirely to escape unfavorable conditions in the temperate zone. It's winter. Everything freezes. Sensitive tissues are easily damaged, and even if they could be growing, there's really no water because it's all locked up in ice. So that's getting them through the harsh winter conditions in seasonal areas. Even in the tropics, where you get a pronounced dry season, you can get dormancy there. Some probation stuff will die back completely woody stuff. Often that just drops its leaves. But even evergreen things can go dormant like you saw with your cactus. But I think a lot about like road entrance, for instance, at least the evergreen species. They just kind of stopped all metabolic activities, or at least slow it down to the point where they're not doing much other than maintaining. So, yeah, it's all just escaping harsh conditions, and that looks different based on where you are geographically, so that makes sense. So in other words, when I'm thinking about whether a plant needs dormant because I often get questions from people saying, Oh, does this plant need to be dormant? Does that plant need to be dormant? Really, you need to have a look at what it's native climbs to assess, whether it needs that dormancy based upon what's happening at different times of year and what the plant might be expecting to undergo in terms of okay, this temperate plant is expecting to be going into a cold British winter and lose all its leaves, um, and then pop back up from its corms or rhizomes in the spring compared to the cactus, which is just going to sit there and wait for things to improve. Yeah, I can't really think of any example where you could just look at a plant and sort of make a prediction about its dormancy needs that you definitely have to do. Your research, which I encourage you to do, regardless of what you're aiming for is like learn something about where these plants come from. What's the seasonality like? What kind of conditions would they experience? And the habitats that they're native to? And you know, the queues for dormancy vary. I mean, sometimes it's day length. Other times it's temperature extremes could be completely hormonal, and you know there's flexibility in that. So, for instance, due to climate change here. Our falls and springs are getting much more mild, so plants go dormant later and kind of wake up a little bit earlier. But they still being from a temperate zone, have that evolutionary sort of momentum, I guess you could say to require dormancy. In fact, plants from temperate zones most of the time absolutely require that dormancy period, depending on how long it is, uh, in order to, you know, maintain themselves long term. Yeah, that's a really good point. So plants must have some kind of internal body clock to know when they are. How are they doing that? Is that just by sensing the conditions changing, they were getting down to sort of heavy botany here. But is there a way you can explain that to me in a way that even I will understand? Sure. And it's going to vary. And to be fair, I don't fully understand. And I don't think actually, most scientists studying on a daily basis, reassuring, but yeah, Yeah, I like I like, uh, the never ending mysteries of the plant world. But yeah, usually it's I, I would say, is most often environmental cues. So for any of the temperate species that I like to grow here or that you're growing over there. Generally speaking, it's going to be the chill period, and so they kind of measure it in the same way I think they plant would perceive relative day length to night length. It's how many hours or days do, in a bigger sense, are you experiencing very cold temperatures versus warm temperatures, and so is that length starts to grow more cold temperatures than you're getting warm temperatures. That's a cue that okay, we're heading into a season defined by extreme cold and ice. Um, you know, sometimes that's also day length to that can also influence it. So as the days shorten, that's another queue to a plant to say Okay, we're heading into the coldest months of the year. Time to start winding things down again. It's going to vary. The hormones involved are pretty complex, and I think we're still discovering which ones are involved to what degree. But I think a lot of it is kind of a mix of environmental cues and just sort of hormonal rhythms within a plant based off of those, and presuming again, it varies whether dormancy. Our lack of dormancy impacts on the plant. I'm thinking of. You know, some people growing succulents don't really change their conditions in the winter and just keep them in them at the same kind of temperature and light levels. Presumably, those kind of plants are able to cope with that, whereas perhaps a plant from temperate region that's expecting to lose its leaves over the winter might have more of an issue. It just depends on the species and so on. Yeah, so if you try to keep most temperate species going, even if you could somehow flight their innate ability to just go dormant, you would burn them out. It would just be like keeping that flame going at high speed all the time. It's it's almost like they need that rest, period. But for a succulent, you know, from a desert that doesn't really get a ton of seasonality, maybe it does have a rainy season. I think those conditions are more tied to just the local growing conditions, and so if they stay favorable, so you're growing these in a warm house under heavy powered lights during the winter. And like you said, don't really change much. You could keep those going, probably to infinity and beyond. Provided again. You're meeting all their other needs. So yeah, it's again goes back to sort of the habitat and the environmental cues that they're relying on to go into dormancy and what they would experience when they do decide to go into dormancy. I mean, like, all things, it's experimentation, and everyone's home is going to be different. I mean, I'm sitting here with my Captain cycling's, which I'm kind of. I have watered them a little bit this winter, but I haven't. They haven't had much, and I'm sort of teetering on the brink of maybe giving them some water. But certainly the Algarve is in my unheated greenhouse will not be watered for a bit yet because I live in fear of the collapse I've seen so many, especially this winter. I think it's been a harsher winter here, and I've seen so many people posting pictures on social media of cacti that, like you, touch them and they just dissolve, um, and really tragic, tragic images of like, succulents that have suffered. So yeah, I'm not gonna I'm not gonna break mine out of dormancy too early because, yeah, that might end really badly. And I've done quite well this year. Have not lost any one dodgy looking at Garvey. But yeah, it's it's all going so well. Well, the next. The next challenge is bringing my captain succulents that have been inside out to the greenhouse without them getting sunburn, because obviously there they've been used to being inside. So that's that's the big one, where I have to kind of have the fleece ready to be shuffled about. And, yeah, the challenges of being a plant parent are considerable. But, hey, it's all part of the fun. The spring is always this delicate balancing act of Should I water? Is this enough light? Is this too much later? God, yeah, yeah, it really is. It's It's tricky time. But you know, I get I like plants that have a bit of a rhythm to them and or, you know, do sort of die back. I think it's kind of fun. I guess that's why I like the dictionary, adds like Smithy answers and things just because I can. Just right now, they've been dead in a pot for a while, and then I'll just start watching them again and they'll spring out, which is kind of fun. But I know lots of people don't have the places to store pots of soil with nothing in them so highly limited by space. Yeah, exactly, exactly.