I receive so many questions here, on my videos and via email. I decided to start a segment called “Ask Nell” because you all might have the same questions and/or be interested in the answers. The first one comes from Patti regarding her Giant Bird Of Paradise, or Strelitzia nicolai.
The photo you see above was sent to me by Patti. These plants are native to subtropical coastal forests of South Africa where the humidity is higher and there’s more rainfall. This is especially true in California these days as we’re in the midst of a mega drought; yes, it’s extreme. It’s common for the edges of these plants brown but nowadays they’re downright crispy because even the maritime layer, aka fog, has been almost nonexistent.
You can see my Giant Bird of Paradise in this video as well as the Bird of Paradise you are probably more familiar with:
Also, you see a lot of split Giant Bird Of Paradise leaves and that is because of the wind. As with most plants, the older leaves will brown, yellow and split more than the younger ones. The leaves get browner and more raggedy as they get older. They don’t need much water at all once they get established but we haven’t been receiving enough winter rain to hold them through our dry months. After all, they do need some water … not no water.
So Patti, water yours deeply every 2-3 months (until we get some substantial winter rains) and give it a 2-3″ layer of some rich, organic compost to help hold that moisture in. The compost will also enrich the soil naturally making the roots and the plant grow stronger.
- Reading The Leaves: 10 Causes And Cures For Foliage Problems
- 1. APHIDS
- 2. SPIDER MITES
- 3. THRIPS
- 4. WHITEFLIES
- 5. POWDERY MILDEW
- 6. NITROGEN DEFICIENCY
- 7. PHOSPHORUS DEFICIENCY
- 8. POTASSIUM DEFICIENCY
- 9. HEAT STRESS
- 10. OVERWATERING
- Curling Potted Plants – What To Do About Curled Houseplant Leaves
- Curling Potted Plants
- Why are the outer edges of my plant’s top leaves starting to curl?
You can reduce the brown edging to an extent but if your Giant Bird Of Paradise is in a windy area, the leaves will split. Nothing you can do about that!
I’m including a bit about the Bird Of Paradise, Strelizia reginae, in here because the same applies to them. It’s not as noticeable on them because their leaves are smaller and seem to be a bit tougher. I’ve been noticing quite a bit of leaf curling on these plants around town because we’re so darned dry.
If you happen to have 1 as a houseplant and the edges are brown, it’s because the air in our homes is much drier than they’d like it to be. The average home is not the subtropics after all!
Thanks for the question Patti. If any of you have a question for me regarding plants, flowers and/or gardening, simply leave it below this post, in the video comment section or send it to [email protected] (if you do this, please put “ask nell” in the subject line). Now let’s get gardening and make the world a more beautiful place!
The Giant Bird Of Paradise flowers are huge by the way. The birds LOVE all that sugary nectar dripping out of them!
Reading The Leaves: 10 Causes And Cures For Foliage Problems
The leaves on your indoor plants are trying to tell you something. When they’re uniformly green, open, upright and growing vigorously, your plants are well-cared for and healthy. If, however, the foliage is wilted, spotted or in any way less than robust, your plants are likely to be suffering from a pest, disease, nutrient deficiency or other problem. With this quick guide on ten foliage problems, you can just check the symptoms you see, then identify the cause and learn how to solve it.
SYMPTOMS: Leaves develop yellow spots, then wilt. Black mold growing on top of leaves.
CAUSE: Aphids are tiny pests that can be red, green, black, brown or white. They cluster on the underside of leaves and suck the sap from them. This causes the yellowing and wilting. The pests also transmit viruses from plant to plant, which can lead to stunted growth. As aphids feed, they excrete a sticky substance referred to as “honeydew,” in which black sooty mold grows.
QUICK FIX: Spray aphids with potassium salts of fatty acids (insect-killing soap), which weakens the pests’ waxy protective outer shell and causes them to dehydrate. Be sure to target the pests on the bottom of leaves, too.
PREVENTION: Aphids produce as many 12 new offspring per day. Use insecticidal soap spray twice – once for the first application then 5 to 7 days later to get the next generation. Check underneath leaves every week to catch any new infestations.
2. SPIDER MITES
SYMPTOMS: Tiny pale specks on leaves or light, white webbing on leaves or buds.
CAUSE: Spider mites are minuscule relatives of spiders with four pairs of legs, no antennae and sharp mouths that pierce plant cells and suck out the fluids, leaving behind yellow, orange or white speckles. A single spider mite female can produce thousands of new mites in less than a month, so they can quickly become a real nuisance.
QUICK FIX: Isolate infested plants from others and spray them with a formula that kills the eggs and the larval stages as well as the adults. A blend of pyrethrins, a nerve agent made from chrysanthemums, and neem oil, a natural growth disruptor, combined with insect-killing soap wipes out all stages of the pests without harming plants, people or pets.
PREVENTION: Spider mites often spread from garden to garden on clones. Before bringing a new plant into your indoor garden, give it a thorough bath on tops and bottoms of leaves–spider mites need dry conditions — and keep it isolated from others for a week while you check the underside of leaves for signs of the crawling pests or their tiny egg sacs.
SYMPTOMS: Silver or bronze colored streaks on leaves, which eventually turn brown, dry and crumbly.
CAUSE: Thrips are minute (less than 1/25 of an inch) insects that can be yellow, brown or black. To the naked eye, they look like tiny threads. The pests feed by puncturing plants and sucking out the sap inside, creating the streaks. Thrips also attack flower buds and can spoil your entire crop.
QUICK FIX: Spray affected plants with a neem oil solution, which interferes with thrips’ rapid growth by keeping them from molting properly. Neem stays active for 5 to 7 days — repeat the treatment two to three times at 7- to 10-day intervals to ensure you’ve eliminated all of the pests and any new generations hatching.
PREVENTION: Check often for the presence of thrips by giving plants a gentle shake. The larva are wingless and will leap when jarred. Apply neem immediately when you see the pests to stop this fast-growing population.
SYMPTOMS: Stunted or twisted leaves, white spots or black moldy areas on the top of foliage.
CAUSE: Whiteflies are small, moth-like insects that cluster on the undersides of leaves. The nymphs are translucent and can appear to be the same color as the leaves. Both nymphs and adults suck the fluids from new growth, which causes fresh leaves to be stunted or twisted. Like aphids, whiteflies secrete honeydew that is colonized by black sooty mold.
QUICK FIX: Spray the pests and foliage with insect-killing soap — it stops the feeding and weakens the insects’ natural protections.
PREVENTION: Whiteflies are drawn to the color yellow, so set up yellow sticky stakes or sticky traps to capture them and help you monitor the pests. The traps alone can protect a few plants, but in larger indoor gardens they work best as an early warning system so you can notice an infestation before it spreads.
5. POWDERY MILDEW
SYMPTOMS: White to gray powdery coating, especially on young leaves. Blistered areas on leaf edges that causes them to curl upward.
CAUSE: Powdery mildew is a disease that shows up most prominently on new leaf growth. Flower buds may be white on the outside and never open. Eventually, severely infected leaves turn brown — the coating blocks light from reaching them — then drop. The fungi flourish in highly humid conditions and where there is little ventilation.
QUICK FIX: Apply sulfur-based fungicide spray to the tops and bottoms of leaves at first sign of the white fungus. The sulfur creates conditions that prevent it from growing and spreading.
PREVENTION: The dampness in indoor gardens are ideal for this fungi Allow lots of room between plants so moisture can evaporate and use fans to create a gentle breeze that helps refresh air and keep humidity in check.
6. NITROGEN DEFICIENCY
SYMPTOMS: Lower leaves look yellow and become soft and curl inward, then turn brown and crispy before falling off completely.
CAUSE: Nitrogen deficiency always affects the oldest (lowest) leaves first, because when new leaves aren’t getting enough of the nutrient to sustain their growth, the plant redirects it from the existing leaves. As plants get close to harvest, it’s normal for them to show signs of a nitrogen deficiency. At that stage, you want the plant to direct all of its energy into the fruit or flowers rather than growing new leaves. That’s why “bloom” stage nutrient formulas are relatively low in nitrogen.
QUICK FIX: Give plants in their vegetative growth stage a high-nitrogen nutrient formula. Fertilizers made with fish tankage (decomposing processing waste) deliver a strong dose of nitrogen in a form that plants absorb and use quickly.
PREVENTION: A regular dose of an amino-acid supplement in your feeding program ensures that your plants always have access to all the nitrogen they need. Amino acids are building blocks of protein that help plants take up and use nitrogen.
7. PHOSPHORUS DEFICIENCY
SYMPTOMS: Lower leaves look dark green or bluish and appear shiny. May have splotches that look brown or bronze. Affected leaves curl downward.
CAUSE: Phosphorus deficiency usually shows up first at the bottom of the plant (on the oldest leaves) and progressively climbs up the plant if untreated. For many crops, the need for phosphorus peaks during the transition from vegetative growth to budding.
QUICK FIX: When your plants near their full-grown size add bone meal-based supplements, which are rich in phosphorus, to your regular feeding program and increase the dosage (following package instructions) as the buds begin to form. Bone meal is a natural source of phosphates in a form that plants absorb and use readily.
PREVENTION: Cooler temperatures and dramatic temperature swings can inhibit plants’ ability to take up phosphorus. Keep the temperature in your grow room consistently between 65 degrees F and 75 degrees F.
8. POTASSIUM DEFICIENCY
SYMPTOMS: Leaves all over the plants are yellow or brown, with tips and edges that appear burned, while the veins remain green.
CAUSE: Potassium deficiency can look like the lights are burning the leaves, but if your plants are at least 12 inches from high-intensity fixtures or you’re using cool LEDs, the problem of burnt-looking leaves is a lack of K. Plants need high levels of the nutrient especially during their budding and flowering stages.
QUICK FIX: Switch to a high-potassium fertilizer during the budding phase of plants’ growth. Molasses in the formula helps plants take up and use the potassium.
PREVENTION: Even if you are using a high-potassium “bloom” fertilizer, the plants may not be absorbing it all because the pH of the nutrient solution is too high. For soil-grown plants, be sure the pH is 6.0 to 7.0 and for hydroponic crops keep the pH to 5.5. to 6.5.
9. HEAT STRESS
SYMPTOMS: Edges of leaves curl inward and form a cup, even when the lights are off. The upper leaves are most affected.
CAUSE: Heat stress causes rapid evaporation, so plants curl up to conserve moisture. Plants too close to high-intensity lights are prone to heat stress, but it can be a problem in any room where temperatures are persistently above 80 degrees F.
QUICK FIX: Set up fans to blow out hot air and bring in cooler fresh air.
PREVENTION: Monitor the temperature not just in the room, but around the upper surface of plants. Maintain constant ventilation and allow sufficient space between plants and lights.
SYMPTOMS: Drooping leaves, curling downward from the stem to the tip.
CAUSE: Overwatering is a more common problem in indoor gardens than under watering, but it is not always the result of giving plants too much moisture. Inadequate drainage of containers or watering hydroponic plants too frequently can also lead to the symptoms of watering.
QUICK FIX: Allow plants to dry out and then gradually increase water as plants recover.
PREVENTION: Water soil-grown plants only when the top inch of the soil is dry (stick your finger in it to check). Be sure excess water drains away quickly from plants’ roots in pots or in flush-and-drain hydroponic systems. Don’t put small plants in big containers, because the soil will hold extra moisture that the roots cannot absorb.
Curling Potted Plants – What To Do About Curled Houseplant Leaves
Are your houseplant leaves curling and you don’t know why? Curled leaves on indoor plants can be caused by a variety of issues, so it is important to understand the various causes so that you can take effective action. Let’s take a look at the main causes and solutions for curled houseplant leaves.
Curling Potted Plants
There are a number of reasons your houseplants may be curling and can include any of the following:
Various pests can cause leaves to curl. Sucking insects, such as aphids, can distort leaves and cause leaf curling. Aphids are soft bodied insects that are normally found on the undersides of leaves and at the growing tips of the plant. If you spot some, spray with insecticidal soap. Use repeated applications until they are gone. If there is a severe infestation, you can cut off those areas of the plant.
Thrips and whiteflies are also other insects that can cause curled houseplant leaves.
Too Much Water
When your potting soil stays soggy for too long, this can also cause curled leaves, as well as lead to root rot. In order to avoid curling leaves due to soil that is too soggy, always allow the top inch or two (approximately 2.5 to 5 cm.) of soil to dry out.
Always use pots with drainage holes. Allow water to completely drain away after watering and never allow your potted plant to sit in water for extended periods of time.
Too Much Light
Too much light, for your plant in question, can also cause leaves to curl. Especially when older leaves are curling at the very tips of the leaves. In conjunction with this, the newer leaves may be smaller than normal and may have brown edges.
To fix curling leaves from too much light, move your houseplant to a location that receives more appropriate light for the type of plant that you have. Also, get to know what acceptable light requirements are for your specific plant.
There are many reasons why you may have curled leaves on indoor plants. Try and identify the actual cause and then take the recommended action to fix your issue.
Why are the outer edges of my plant’s top leaves starting to curl?
There are several possibilities regarding what could be causing your curling leaves. Curled leaves that are not accompanied by any necrosis or browning of the foliar edges may be attributable to nutrient excess, insect damage, water, other cultural issues, or even possibly the genetics of your plant.
There is no way to give you a definitive answer without having some background information, but we can cover some of the most likely possibilities.
Not enough water can cause this symptom, but if it does not correct itself after a good drink, this is not likely the issue.
Conversely, the leaves of an oversaturated plant may curl or droop, but often this is followed by a yellow and or sick appearance of the plant too. Too much water and poorly drained soil may also set the stage for root rot, which will cause the leaves and ultimately the entire plant to collapse.
If you are growing these plants in containers or planting beds and not hydroponically, make sure that the media you are growing in is well-drained and porous so that excess water can drain through. A moisture meter can help to identify how wet your media is and whether or not this may be the cause.
Too much nitrogen to the point of toxicity can cause curling leaves as well. Performing a simple soil or media analysis will help to rule this possibility out or in depending on your results.
Your plant may also just be showing signs of stress due to cultural factors. Is the curling just on one side? This could be an environmental problem due to continual and proximal exposure to a fan.
Another likely culprit that can be easily checked and remedied is if you are growing these plants in pots and if they have become root-bound. If this is the case, scuff up the roots and pull them away from the root ball before transplanting them into a larger container.
If none of these seem to be the cause of the leaf curl that you are experiencing, the symptoms may be caused by a mite infestation.
Several different species of mites, including Broad mites, Cyclamen mites, and Russet mites may be feeding on your plant leaves and leave curled leaves in their wake as a result of a substance that they inject into the foliage while feeding.
Generally, though, there will be other symptoms appearing shortly after you notice the curling such as a change of color (yellow to brown) or a speckled appearance to the leaves.
If you have ruled out all of the above, there is possibility that the particular species of plant that you are growing has the naturally tendency to have curled leaves. This is not an unknown characteristic of some strains of plants.