Episode 258: Q&A special
Homalomena rubescens, the shield plant. Photograph: Dinesh Valke on Flickr.
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Transcript
On The Ledge podcast
Episode 258
SUMMARY KEYWORDS
plant, mealy bugs, thrips, houseplants, seeds, peat, substrate, lynn, question, bit, foliage, pot, rhizome, hagen, ledge, water, week, succulent, deal, grow
SPEAKERS
Jane Perrone
Jane Perrone
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Jane Perrone
Slanket on: check! A cup of tea by my side: check! Microphone in the right position: check! That must mean it's time for On The Ledge podcast! I'm your host, Jane Perrone, and in this week's show, we're tackling questions, questions, questions! All those conundrums you've been dealing with about your houseplants. Well, things are getting seedy around here! Yes, the On The Ledge sowalong launched last week and lots of you are already getting involved. If you haven't listened to that episode yet, go back and listen to episode 257, where I introduced the On The Ledge sowalong - my mission to get everybody growing houseplants from seed! I'd love you to join in with that. It's very simple, but if you're feeling intimidated, I'm thinking of doing - is this nuts I don't know!? I'm not sure if this is a good idea or not - but I'm thinking of doing a YouTube live On The Ledge sowalong episode. Would that work? Maybe I'll give that a go. Could be fun. For the moment though, I'm just going to round up some of the things that people have been talking about on the old socials regarding this sowalong. If you want to post on social media about your sowalong efforts, you can use the hashtag 'otlsowalong' and that's exactly what Elspeth did, on our Facebook group, Houseplant Fans Of On The Ledge. Elspeth has ordered not one, not two, but three types of Euphorbia seed! I wonder what they are? Euphorbias are fantastic, often mistaken for cacti, but I've never grown any from seed. So, let us know how you get on Elspeth, and Chris, meanwhile, is embracing the sowalong in a different way. As I said last week, if you don't want to sow seeds, that's fine. You can plant a bowl or you can do some cuttings. We allow vegetative propagation around here because we are not sticklers, so Chris has been propagating a blood lily, planting Caladium Galaxy and restarting an Achimenes, the hot water plant. I don't think I've ever mentioned Achimenes in the podcast before? I don't grow them. I have grown them in the past and found them not that easy, but yeah, great to hear that Chris, and let me know how you get on! Over on the 'gram, the Instagram, meristemUK, always very active with the sowalong, has found that Tylecodon paniculata seeds have germinated within a week. Now that's the kind of seed-sowing I like, where you get a quick result because I am Mrs. Impatient, or should I say Ms Impatient!? And Leafy Exotics has again been challenging my ability to pronounce scientific Latin! They have the year's first Dendroseris litoralis seedling! I don't even know what that is!? I'm gonna guess it's a succulent. I need to go and Google it afterwards. Si has started chamomile, oregano, or 'or-e-gano' if you prefer, nasturtium and celery seeds for the sowalong. Oh, you're making me want some pickled celery now! Have you ever had pickled celery? It's amazing. Even if you don't like celery, try pickling some celery. It's very good. If anyone wants the recipe, just let me know! Laura has sown Queen of the Night seeds. Now this I'm excited about. I can get on board with this one. That's a fantastic plant and wow, what a journey you're to go on with those tiny seeds ending up, hopefully, with a massive succulent that produces enormous scented blooms! Loving that! And Thoseleavesthough has been sowing Anthurium seeds. Again, they seem to be much more available these days, so definitely worth a punt, if you can get hold of some via one of the Facebook groups, or other groups that are swapping and selling Antherium seeds like crazy at the minute. So that's a summary of On The Ledge sowalong so far. We'll be coming back to it regularly, as spring progresses. Do get involved, let me know what you're doing. If you're not on social media, you can just drop me an email to ontheledgepodcast@gmail.com.
Jane Perrone
Let's crack on with the questions and the first one comes from listener Hagen, who's also a patron of the show. Thank you for that, Hagen! And this question is about thrips. I think of them as the greyhounds of the houseplant pest world because they're very slim and long and fast moving! That's just my thoughts! Anyway, if you're looking for the damage that's caused by these plants, it's usually kind of a silvery stippling on the leaves to start with and then you get severe leaf drop. They are a quite tremendous pest for houseplants if they get a hold on your plants, and unfortunately Hagen had multiple philodendrons with severe thrips infestation, so, very sensibly, Hagen decided to chop everything back and save the top cuttings, and those have grown into plants again, but Hagen wants to know, "Can I reuse the potting mix that has been on the balcony over winter?" It's been exposed to several days of frost in a row, sometimes with temperatures down to minus 10 Centigrade. That's about 14 Fahrenheit. Now, Hagen goes on to say that having listened to my thrips episode, which I'd advise all of you to go and listen to as well, that's episode 204, they know that thrips, when they get to the pupal stage, the larvae end up in the soil underneath the plants. So, Hagen is wondering, do those baby thrips and the pupae survive freezing temperatures? Will a winter on the balcony have ridded the potting mix of thrips? Now, if you have listened to the thrips episode, you'll know that I talked to Professor William Kirk, who has dedicated his life to studying thrips, and fortunately I was able to tap him up for an answer to this question because I really wasn't sure about the answer. And I'm glad to say that Dr. Kirk gave a full and interesting answer. And it's a bit of a mixed picture. Dr. Kirk says that the adult thrips are usually the most hardy stage and can survive with no food for several months and occasional freezing temperatures. Well, that's where the greyhound metaphor ends because I can tell you no greyhound's gonna like being cold and hungry. But Dr. Kirk goes on to say, however, adults only survive this long if allowed to adjust slowly to cooling temperatures, as happens outdoors, or in an unheated glasshouse in autumn. This is a process called 'cold hardening'. They tend not to survive for long if moved straight from a warm room to freezing temperatures. Even so, they are surprisingly cold resistant for short exposures. For Western Flower Thrips, 50% of adults die after seven days at minus five degrees centigrade. The longer you leave them, the more die, they would all die after a couple of hours at minus 20 degrees centigrade, about domestic freezer temperature. About 20% of larvae can survive a couple of hours when moved straight from 20 degrees centigrade to minus 11.5 degrees centigrade. Some would expect adults to survive longer. I would suggest several days, particularly if cooled slowly first. So from that answer, Hagen, I would say there is a chance that you still have some thrips in that potting mix and I personally would not risk potting houseplants up in that mix again, just for the sake of avoiding further heartache. If you know somebody with a compost heap, or can you put it on a flowerbed outside somewhere so that it doesn't just go into landfill? That's probably the best thing you can do with this mix. I personally wouldn't risk it, although I suspect, from the stats that Dr. Kirk has given us, the likelihood is most of those trips will be dead. Do you want to risk it? I don't think I would. And I was also able to ask another listener question about thrips to Professor Kirk, and that came from Emma, and everyone wanted to know this: would adding a layer of damp sphagnum moss on top of the substrate of houseplants help to deal with a thrips infestation. And Dr. Kirk's answer to this one is quite unequivocal, damp sphagnum moss over the substrate would give the thrips a nice, humid environment in which to pupate, after dropping from the plant. It would probably help the thrips! If you replace the moss and destroyed the old moss every couple of days, you might remove and kill a lot of pupa over time, but that would be rather wasteful of sphagnum. So there we go, two thrips questions answered, and, as I say, if you are still a bit in the dark about thrips, if you've never had them, then you're probably happy to remain so, but let me tell you, when those little mini greyhounds start attacking your loved ones, you will want to know the answer of how to deal with them, so do go and listen to episode 204, if that's the case, for more from Professor Kirk! The next question came in on Twitter - where you can find me as @janeperrone, and also @houseplanthour - and this one came from The Happy Plotter, who has a Caladium, bought last year, that was full of foliage, but gradually, each leaf died back and we're left with a pot with a bit of brown stick in it. I think anyone who's grown a prayer plant, ever, will probably identify with this, and, unfortunately, this is the second plant that The Happy Plotter has lost, so, of course, they're wondering "Is it dead? Do I water it? Can it recover?" And whereas with some houseplants, the answer is a flat "No", with prayer plants, there is often a chance of reviving these specimens. I've had this happen to me before, when spider mites have attacked, or the plant's just got really miserable and all the foliage has looked terrible. I've chopped it off and started again. So, where do you get started with this approach to bringing your plant back to life? Now - springtime - is a great time to start this because days are getting longer and the plant will be stimulated to grow. You just need to give it a bit of a helping hand. So, step one is to have a look and assess your chances of success to start with because there's no point in spending time on this pot of potentiality without checking the likelihood of it actually working. So, I would take the plant out of its pot and have a look at the roots and look for a lumpy firm bit of plant tissue in the form of a rhizome. This is what members of the Maranta, the prayer plant, family grow from and you want to check that there is a rhizome there and that it feels reasonably firm and isn't all mushy because if it's mushy, then your chances of success are pretty much zero. So have a look, see whether there's a root ball still and what state that's in. Are the roots firm and sweet-smelling, or are they slimy? Cut away anything that is slimy and have a feel of that rhizome. Check that it has some firmness. If it's a 50/50 situation, you can still cut away anything that is rotting and have a go, but it may not succeed. So that's worth doing first off, then stick the rhizome back in the pot. If, looking at the potting mix, you think "Oh, this is not looking good!", then you could replace that potting mix with fresh potting mix.
Jane Perrone
Place it in quite a small pot, don't overwhelm the rhizome with a massive pot, and then it's a question of providing it with the conditions that make for good sprouting. So our major tool here is a clear plastic bag into which you can put the whole pot and then seal it up again. So you're providing a little mini greenhouse for the plant. So it can have good humidity, protection from drafts and a steady temperature. Then put it somewhere warm, not in direct sunlight, but giving a bit of light. Maybe stick it under a growlight, if you can, and you should find that plant will start re-sprouting in the next few weeks. I'd give it at least six weeks to get going. If you don't see growth after six weeks, the likelihood is it's probably not going to do anything. You should see that new growth coming. Keep it in the plastic bag for a while and then gradually start hardening it off by taking the plant out of the bag for increasing amounts of time, until the plant is acclimatised to the room conditions again. And I would say, you know, sometimes these problems are caused by a spider mite infestation, but if you're going to revive this plant, it's really worth spending some time reading up on what it needs in order to make sure that you don't go through the same kind of heartache again. What does it need? Well, these are plants that do need quite reasonable air humidity, at least 50%. They like to be grouped with other plants. Keep an absolute eagle eye out for red spider mites. Look out for that white grainy stuff on the backs of leaves and treat as soon as you see it because that is the thing that will take these plants down in no time. But hopefully, if the plant, from the beginning, gets acclimatised to your home, it may have more chance of success than a plant that you've brought home from a nursery and it's come from the picture-perfect nursery conditions to your home and then just protests very dramatically by losing all its leaves! So good luck there, Happy Plotter, and let me know how you get on!
Jane Perrone
Short break from the questions for a bit of housekeeping and also this week's fact from m' book, Legends of the Leaf, coming out on April 27th. Thanks to all of you who have pledged and pre-ordered and this week's fact concerns Crassula ovata, the Jade Tree, and if you're familiar with the succulent world, you'll know that many succulents have evolved different ways of making themselves unattractive to herbivores that might want to snack on them because, of course, in an environment where water is limited, and they store that water in their plant tissues, that's the succulent bit. Hanging on to foliage is really important, but if you look at Crassula ovata, you may be wondering, well how on earth is this plant doing that? The jade plant isn't bothered by becoming a snack, because that is how it spreads. So there are many creatures that will feed on the jade plant in its native climate, which is in South Africa, including things like giraffes, rhinos, springboks, kudus. They'll all attack all the plant from above. And then underneath, at ground level, you get leopard tortoises, which are going to come up and nibble the lower branches. But actually, this works out pretty well for Crassula ovata because herbivores tend to be messy eaters and inevitably, some of the foliage that they break off drops to the ground. And indeed, this plant deliberately makes itself a little bit fragile. So, in high winds, as the plant grows big and, indeed, this plant can get to around three or more metres tall in high winds, bits will fall off, but that's okay because the plant is designed to root even from a section of leaf. If you've ever had a Crassula ovata leaf that's been knocked off and it's been left on the ground, you'll find that it will start rooting and growing into a new plant, and that's exactly what the plant will do! It roots and spreads itself around via pieces of the plant being dropped to the ground: more opportunities to spread. So take advantage of this! If you do have a piece of jade plant knocked off, then you can just sit it on the side for a couple of days and then maybe press it into some damp, gritty compost and it will grow into a new plant! Very handy! So that's my fact from Legends of the Leaf this week and I'll be back with another fact next week, and details coming up about my virtual launch parties for the book. There's going to be two: one for the people who've pledged and my Patreon subscribers, and another open invitation for everybody. They'll be happening in early May. More details about those events to come. On with the questions and this one comes from Eva, and Eva wanted to know if there is a source for peat-free carnivorous plant compost in the US. This was as a result of listening to episode 245, my update on peat-free houseplants. If you are a long-time listener, you'll remember that I interviewed Sean Higgs, who makes Thrive peat-free carnivorous plant compost, way back in episode 103. So it was to Sean that I turned for an answer to this question, and at the moment, the answer, depressingly, is probably not. Generally, the US is far behind the UK in terms of getting on the peat-free wagon. I think that's probably because it's perceived that there's a massive source of peat in Canada which will never run out and therefore it's okay to continue using peat willy-nilly in horticulture. Now, I don't believe this to be true because there are a million and one reasons to keep peat in the ground, climate change and biodiversity being among them. So the US is catching up slowly. Sean couldn't give me much in the way of concrete information, but he said change is on the way, research is happening, and within a few years there should be peat-free, carnivorous plant substrate available in the US. If anyone in the US has knowledge of something available now, I'd love to hear it, but for the moment, it's a 'hurry up and wait' situation, which is frustrating for those outside the UK who want to grow in a peat-free medium and just don't have access to products like Sean's Thrive product, or, indeed, Wax Wicked Plants in the UK, another carnivorous plant grower, also offers a peat-free mix. The situation is changing all the time, though, and research is ongoing. So we hope this changes soon, but for the moment, I'm afraid either it seems like the answer is no, unless I hear any more intelligence, in which case I'll pass on what I can. The next question comes from Lois and concerns Homalomena. I'm never quite sure how to pronounce this particular plant genus: Homalo, Homa-lamena?! Homalomena, do-dooooo-do-do-do! I genuinely don't know on this one! It's often known as the shield plant, if we want to use the common name, and Lois is wondering why this plant doesn't get much of a mention in houseplant books, though. Lois writes: "I saw one in a shop abroad and stopped breathing for a moment, it was that beautiful! I had to have one but couldn't find them anywhere in the UK". Now Lois did finally track one down and says it is the most rewarding and gorgeous plant. Thinking about my own houseplant books, yeah, I can't remember seeing this in many, if any, of those books. I've had a look in the "Gold-Plated Houseplant Expert", by David Hessayon, one of my much loved houseplant bibles, It's not in there. It's not in the Reader's Digest book of houseplants, which, again, another classic tome that is pretty comprehensive: not in either of those books. I did find it though in another classic, which probably isn't so much of a mass-market book, as a specialist book. It's called "Tropical Foliage Plants: A Grower's Guide" by Lynn P. Griffith Junior, and Homalomena does get a mention in this book under "Other foliage varieties", and notes that it's rather new to the foliage trade. It's a tropical aroid, native to India and Burma, and it says that Emerald Gem is the most popular cultivar, with Purple Sword and Selby two other varieties in the trade. So it then goes on to give some care description for the plant and says that it's care is similar to that of philodendrons. So this book came out in 1998, so it seems that it's one of those plants that has come onto the radar of houseplant people in the last few years, although, like a lot of plants, you find that, actually, it has been grown before, we've just, kind of, forgotten about it in decades gone by. And, indeed, the genus as a whole was first written about scientifically in 1832. And the plant that's available right now, most widely, is often called Homalomena Maggie, and I think this is either just the plain species, Homalomena rubescens, or possibly a cultivar thereof. As ever, it's a little bit tricky to find out the origins of these things, but I have a Homalomena, it was a gifted plant that came from the website sprouted.com. and I've found it, so far, to be extremely easy. It's on a par with the Swiss cheese plant, Monstera deliciosa, in that it just sits there and does its thing. Now that may be because I was sent a very large, mature plant of about five foot tall! So, oftentimes, when you're dealing with a much smaller specimen, they're more vulnerable to any problems than a big plant, which is already kind of pretty tough and can deal with fluctuations in conditions, but as I say, I found it a relatively easy plant, but, unfortunately, Lois has been having problems with her Homalomena, and noticed that it has brown leaf tips and some edges and that it is weeping, or sweating, water from the leaf tips and Lois isn't sure why this is happening, but it's not over watering apparently because Lois is making sure to allow the pot to drain and only watering when the pot rootball feels suitably dry. So what's going on? Well, Lois, without seeing a picture of your plant, it's a little bit tricky to fully diagnose what's going on.
Jane Perrone
You also report that there are white flecks, not dots but long in shape, about a millimetre, and you've been wiping them away as soon as you've seen them. Now, I'd be wanting to get a hand lens on those white dots forthwith because there is the possibility that they are thrips. Thrips do look long rather than dot shaped. So I would definitely recommend getting a magnifying glass, or hand lens, on those flecks and checking what they are. That's a good step forward to diagnosing what's going on with your plant. The weeping, or sweating, well, that's just guttation and usually it's caused by the plant having too much water around the roots. I would definitely want to be taking this plant out of the pot and seeing what's happening down at root level because I suspect that there might be a bit of root rot. Possibly the substrate needs replacing and making a bit more free-draining, particularly if you haven't changed it since you bought it. So I would take it out the pot, knock off all the old substrate, fresh substrate and maybe add some handfuls of fine orchid bark, or perlite, or expanded clay pebbles, just to allow a bit more air to circulate and the water to drain away more quickly because even if you allow the water to drain away and make sure there's not water left in the bottom of the pot, if the substrate itself is holding too much water, then you'll find that that will still be causing a problem. So it's like a sponge. Can you imagine, a really absorbent sponge will hold a lot more water than one that's not so absorbent. Guttation is normal, it's going to happen with aroids like this, it's not unusual, you can go listen to episode 148 with Dr. Polly Schiffman to find out an in-depth description of what guttation is, but if it's happening all the time, then that probably means there is an issue with your plant. Guttation happens when water is forced out of the plant, out of the edges of the leaves, and drops are formed, but if you're getting a lot of guttation, then, as I say, it's probably a sign of too much moisture and it tends to happen more if you water last thing in the evening and that makes guttation worse. So try to water in the morning if you can. Lois does say that the plant has had two new leaves in six weeks, with another five on the way, so I have high hopes for this plant, Lois, I think it's going to be okay. I would just check that substrate, replace as necessary and also check those leaves to see whether you've got a pest infestation, or something else. It's amazing the things that can land on our plant leaves, that you're not aware of until you get that hand lens out! Then you can tell the difference between something that's moving, has got legs and is actually sucking the sap of your plant, such as thrips, or something else like a bit of dust, or something falling from another plant, or indeed the many things that occupy our plants that aren't going to damage them. Among them, things like predator mites, so this is why the hand lens is just so useful. So yeah, Homalomena are beautiful plants. I hope they become more popular. There seem to be a few more cultivars coming onto the market recently. I've seen one called Homalomena Lemon Lime, which is available in a few shops here in the UK. I'm not sure whether that's a hybrid, or what? I did also find out, in the course of my research, that some Homalomena are meant to smell of anise, a kind of liquorice-y kind of smell! I need to go and sniff my Homalomena now and see if that's the case with mine! And I've also seen that Emerald Gem cultivar, which was mentioned in the tropical foliage plants book by Lynn P. Griffiths in a few places as well. So maybe Homalomenas are going to become more widely available? What kind of conditions do these Homalomenas like? Well, they like a good amount of sun. Mine is in my daughter's south-facing room, about a metre away from a bay window and it's loving life there. I wouldn't put it right in a south-facing window in the middle of summer. Humidity-wise, smaller plants are going to suffer if humidity is is low. Temperature wise, I wouldn't put them anything below about 15 degrees Celsius, which is about 59 / 60 Fahrenheit. And, as I say with that substrate, you just need to think about adding extra drainage material and maybe watering a bit more often as a result of that. I've heard that they're quite thirsty plants and I would say that, as I say, if you make that substrate free-draining then you can water them quite generously without any problems. I have seen people say that Homalomena are good for low light conditions. I haven't seen as much proof as I would like to confirm that to be the case. I know Aglaonema, which are another member of the aroid family, from South East Asia, can cope with less light, but I haven't seen enough proof yet that Homalomena are similarly adaptable. So I would generally try to get them closer to a window than you would with an Aglaonema. So that's Homalomena! I'd, as ever, appreciate your thoughts on the matter. What have I got right? What have I got wrong? And do you grow and enjoy this plant?
Jane Perrone
Next up, it's a question from patron, Lynn, and this came up as a result of a 'Repot With Me' Zoom session that I did with Patreon subscribers recently, at the Ledge-End and Superfan levels, and I forgot to leave time for questions at the end! So Lynn followed up with with a question about mealy bugs, and where you draw the line with them - a subject close to my heart - and Lynn, unfortunately, has found that mealy bugs have spread through lots of plants, including Hoyas, Orchids, and Streptocarpus, and despite keeping getting rid of those bits of cotton wool, there are always more and Lynn's asking "Do I need to throw everything away?" And, depressingly, that means a plant swap that started in Lynn's town, is something that Lynne feels unable to take part in, so that's a shame. Lynn says "When they started, I didn't realise how persistent they will become. Apart from giving up on houseplants altogether, is there a solution, please?" So this is a really good question and strikes close to my heart as somebody who has suffered from both mealy bugs and root mealy bugs, and, I think, first I'd say don't give up Lynn! Many, many, many houseplant owners, or specialists of various different types of plant families, including Hoyas and Orchids, would say you are always going to have some mealy bug in your collection. They are very hard to completely eradicate. If you have a lot of plants, if you're bringing in new plants, it's going to be tricky. There are different ways of approaching it and it depends on your mindset as to which one you want to take. Touch wood - touches MDF desk! - I have not had a major problem with mealy bugs. I've had a few mealy bugs in my collection, but, on the whole, they have been dealt with. My problem has been with root mealy bugs, but I think the same advice applies and that is if you mentally conditioned yourself to realise that there will always be a few mealy bugs in your collection, it's a better way to live, than thinking that you can defeat them forever. I just don't think if you've got a domestic collection, and you don't have a huge glasshouse with the option of doing integrated pest management on a massive scale, or using an awful lot of systemic insecticides, that you're going to get rid of mealy bugs altogether. What you can do, is keep it at a controllable level and keep on top of it. If your plants are otherwise healthy, they will survive having a few mealy bugs. That's how they would live in nature. That's how it would be. It's only when we allow that population of mealy bugs to get out of control and really start damaging the plant, that we get a big problem. So the key is keep your plants healthy, as healthy as you can, and deal with the mealy bugs when you see them and do search them out from the places that they like to go and hide, which is mainly cracks and crevices in the plant, particularly around the, what you might call the collar of the plant, where the plant comes out of the substrate, that, particularly in cacti and succulents, is where mealy bugs love to hide. Yes, you definitely could take loads of cuttings of your plant and then treat those cuttings extensively and then re-root those and you probably would end up with a plant that is pretty much free of mealy bugs, but again, you buy one more new plant and then mealy bugs are back in your collection. So maybe that's not the best use of your time, unless a plant is very seriously infested. In terms of swaps, obviously you have to be extremely careful, but you could take cuttings and make sure that you've treated them within an inch of their life and then they probably would be okay to take to a swap, provided you've given them a good amount of time to allow any mealy bugs to reveal themselves. Mealy bugs are very persistent. Yes, they are incredibly so. And often the thing that you can see, those cottony bits from which the young mealy bugs will emerge, and that's why you're not getting them all because there will already be young mealy bugs that have come out of those egg sacks and are wandering around, not visible with the naked eye, and you probably won't spot those and therefore the cycle goes on. So again, I'm gonna get boring here and say "hand lens"! If you've got one, use it, and that way you might be able to spot more mealy bugs than you would do just using your naked eye and you can target the babies as well. And the other thing I would definitely advise, is step up your hygiene. So, mealy bugs, they can survive for a really long time. The crawlers, the baby ones that move around, can manage for a really long time without any food. So you can find them stuck on to the sides of a container, on a trellis, on a saucer, and they can sit there for a really long time and then come back on, to get back on your plants and start breeding again. So really committing to cleaning pots with hot soapy water, cleaning trellises with hot soapy water, and that will will really help to deal with a problem. Also, again, I've said it before, but quarantining new plants really can help to making sure there's nothing on new plants that's going to hitchhike on to your plant. Again, I sound like a broken record here, but do go back and listen to episode 143 with Dr. Raymond Cloyd, Entomologist, who studies these creatures, and there's lots of good advice in there for treating them. One of the things that he recommends, which is worth a try for getting to grips with those babies, is getting a piece of black paper and shaking your plants over that. And that way you'll find the mealybug babies, they'll fall off onto the black paper and you'll be able to spot them before they get going and start breeding. What about the biological control, the mealybug destroyer, Cryptolaemus? I have tried this, I think it didn't work particularly well for my plants, and, generally, I would say if you've haven't got a massive collection of plants and you haven't got a big infestation, like a major league infestation, and you're not a commercial nursery, I would question the effectiveness. Unless you can keep up quite a steady regime of introducing these onto the plants, I suspect there are better ways of dealing with an infestation. As I've already listed above, I'll link again to a video of the lifecycle of mealy bugs, which is really useful to watch. Because it shows you those crawlers, those babies coming out of that cottony mass, and shows you what to look for, and the better you get to know these creatures, the more you can understand how to deal with them. So, Lynn, I hope that brings you some comfort. I would say that I probably don't know a Hoya or Orchid collector that hasn't had mealy bugs at one time or other, so you're in good company. Keep doing whatever you can do to keep them at a low level and continue to enjoy.
Jane Perrone
If I haven't answered your question, apologies, but do keep sending those queries to me because I try to answer a listener question almost every week of the show. I am not one of those plant people who says "Oh, I get sick of answering questions!" I literally never get sick of answering plant questions! So fling a few queries my way! If I can help, I will! That is all for this week's show and I will be back next Friday, for more houseplant-based information, entertainment and chat. Loving you all! Have a great week. Bye!
Jane Perrone
The music you heard in this podcast was 'Roll, Jordan, Roll", by The Joy Drops; "The Road We Used to Travel When We Were Kids", by Komiku, and "Sundown", by Josh Woodward. The ad music was "Dill Pickles" by the Heftone Banjo Orchestra. All Tracks are Licenced under Creative Commons. Visit the show notes for details.
I answer a clutch of listener questions, covering everything from thrips to Homalomena, the shield plant.
Check out the shownotes as you listen…
On The Ledge sowalong
The On The Ledge sowalong is my annual mission to get listeners growing houseplants from seed. I wrote a thread about it on Twitter!
You can catch up with all the sowalong episodes from previous seasons here, covering everything from sourcing seed, how to avoid scams, what equipment you need and how to grow particular types of plant including succulents and ferns.
To take part, just choose something you’d like to grow from seed indoors, and let me know what you are up to, either by emailing ontheledgepodcast@gmail.com or tagging me on social media using #OTLsowalong.
You can share your experiences and ask for advice from other listeners by joining my Facebook group Houseplant Fans of On The Ledge, or joining in my weekly Twitter chat, #HouseplantHour.
Question 1
Hagen has suffered a thrips infestation, and wanted to know whether any thrips could survive in a pot of substrate left outside on a freezing balcony over winter. Thanks to entomologist and thrips specialist Professor William Kirk for answering this one. Prof Kirk says some adult thrips can, if allowed to adjust gradually, survive freezing temperatures and no food for some time. I think there is a chance that Hagen’s pot still has the potential for some surviving thrips, so I wouldn’t risk using it again for houseplants.
Listener Emma also had a thrips question - would putting damp sphagnum moss on the surface of pots where plants are infected with thrips help with the problem? The simple answer is no - the thrips would love this damp environment.
Do go back and listen to my thrips episode where you can hear Prof Kirk offer more insights into the thrips lifecycle and how to deal with them on your plants.
Question 2
The Happy Plotter wanted to know what to do about a prayer plant that had deteriorated to the point where it was a dead looking stick in a pot. Could it survive?
The good news is that yes, this may be possible to revive. Members of the prayer plant family usually grow from an underground storage organ known as a rhizome - so start by taking the plant from its pot and feeling for a firm, lumpy bit which indicates there is a living rhizome which has the potential to shoot.
If that’s the case, pot into fresh houseplant substrate and then place the whole pot into a clear plastic bag and place somewhere warm and out of direct sun. Keep an eye on it and within a few weeks it should start to shoot again.
UPDATE: I got this wrong I am afraid - the actual plant was a Caladium. I am going to leave the recording as it is, as my advice for prayer plants is still sound and has already helped several people. Helpfully the advice for a Caladium would be almost the same, except Caladiums grow from a tuber not a rhizome.
Question 3
Eva wanted to know if there’s a source of peat free substrate formulated for carnivorous plants available in the US. The answer at the moment seems to be no - I talked to Sean Higgs who makes Thrive carnivorous plant potting mix in the UK, and he couldn’t provide any details of products available now, but research is happening so there should be a development on this front in the next few years. Another source of peat free carnivorous plant compost in the UK is Wack’s Wicked Plants. You can hear Sean talking about peat free in On The Ledge episode 103.
Question 4
Lois wanted to know why the plant genus Homalomena - aka the shield plant - doesn’t get much of a mention in houseplant books. I checked out my own book collection and could only find a mention in Tropical Foliage Plants: A Grower’s Guide by Lynn P Griffith Jr which first came out in 1998. Lois also wanted to know why her HOmalomena was ‘weeping’ from the leaves - this is called guttation which is normal for many aroids, occurring usually when there is too much water around the plant’s roots especially at night. You can find out more about guttation in episode 148 of On The Ledge. Making the plant’s substrate more free draining may help.
Question 5
Lyn has an infestation of mealy bugs that she is only just keeping on top of - and wonders if there’s a way she can deal with their persistent presence without getting rid of her plants altogether?
I feel for anyone in this boat - Lyn mentions that the mealies have had a go at her Hoyas, orchids and Streptocarpus. I suspect that pretty much anyone who grows any number of these plants has had this experience, and it is disheartening. My advice is to change mindset - realise that mealies will probably always be present in your collection at a low level, it’s just a question of keeping numbers under control and keeping your plants healthy so that they can deal with the damage mealies do. Remember that it’s not just the cottony masses you need to worry about - these egg nests are where the young mealies emerge from, and the youngsters are hard to spot unless you shake your plant over a piece of black paper. Check out this video on the lifecycle of the mealy to get to know this creature better.
Do check out episode episode 143 for more tips on dealing with mealy bugs.
Want to ask me a question? Email ontheledgepodcast@gmail.com. The more information you can include, the better - pictures of your plant, details of your location and how long you have had the plant are always useful to help solve your issue.
THIS WEEK’S SPONSOR
Thanks to True Leaf Market for supporting this week’s show. True Leaf Market have been supplying of superb seed since 1974: check out their website for a huge choice of seeds including vegetables, herbs, flowers, microgreens and seeds for sprouting, plus their free growing guides to help you get started. Get $10 off orders of $50 or more off now at trueleafmarket.com with promo code ONTHELEDGE10. Limit one use per customer.
HOW TO SUPPORT ON THE LEDGE
Contributions from On The Ledge listeners help to pay for all the things that have made the show possible over the last few years: equipment, travel expenses, editing, admin support and transcription.
Want to make a one-off donation? You can do that through my ko-fi.com page, or via Paypal.
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CREDITS
This week's show featured the tracks Roll Jordan Roll by the Joy Drops, The Road We Use To Travel When We Were Kids by Komiku and Sundown by Josh Woodward. The ad music is Whistling Rufus by the Heftone Banjo Orchestra.