Category : Plant Doctor
I have an amazing espalier rosebush in my backyard this year that is setting records with the sheer amount of blooms on it. Unfortunately it’s also suddenly covered in black spot fungus, and needs some major help right now.
Black spot is caused by a fungal infestation that occurs in wet locations, or humid places. It can be triggered by late evening watering, or misting sprinklers, and it spreads rapidly on roses if it’s not caught right away and pruned out. For bushes with major black spot problems a store-bought anti-fungal spray, or an application of horticultural oil can work adequately, but for the DIYers like myself, a home remedy will fix the problem and save you the gas and pocket money.
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Question: I’m starting my own plants from seeds, and they are turning yellow and dying, why is that?
Yellow seedlings are a product of root damage from either a water or fertilizer problem at the roots. Too much water and not enough air circulation at the roots can cause this, as can a lack of moisture. Double check how much water you are using on you plants, and how often. New seedlings need moisture every day, so use either less water, or change the time of day that you water, so the water feeds the plants and doesn’t either completely evaporate, or lay in the soil overnight, and promote rot. Also identify whether you have been using too much, or not enough fertilizer on them.
Lastly check over your seedling bed, and see if overcrowding could be the problem. Too much competition over natural resources can also cause yellowing and death in new plants.
Question: Why is my succulent getting ‘leggy’ and dying off at the bottom?
Great question! Succulents come from bright, arid climates, and if you keep them in areas of indirect light they will get ‘leggy.’ If you have been keeping this little guy away from a nice bright window, or an indoor grow light now is the time change your strategy, and to make a few cuttings from the top for propagation.
If you have a rooting powder, take a cutting off the tops of the plants, dip the cut end in the rooting powder, and plant them in a dish with a good succulent potting mix. Keep the new cuttings in a moist, bright area, and wait a few weeks for new root systems to develop. Once the cuttings are ready for transplanting you can start over with your new plants.
Whitefly can become a nuisance year-round for your favorite indoor plants, and over-wintering outdoor plants inside through the cold weather can sometimes compound the problem by bringing new insects into the house. Pesticides in granular form can take care of this problem for you, but for those of us with pets, children, or the desire to use something less toxic, there are solutions that will help you gain control of your problem. Ideally you will want to eliminate all the life stages of Whitefly that may be living on or around your favorite houseplant and do it quickly. Adult Whitefly are not only deadly to plants due to their feeding methods, but they are also carriers of plant diseases from one plant to another. (more…)
Devil’s Ivy Raphidophora aurea and Epipremnum aureum
Wondered why your multi-colored Devil’s Ivy Leaves have changed their color permanently?
The leaves of this plant will change from a bright green and yellow spotted leaf designs to a solid green color if the plant is not getting enough light. It’s just that simple! Although this office plant does well in many situations and isn’t something to thrust into bright light, with minimal lighting it will actually produce only solid green leaves, and literally change it’s spots.
As more office buildings are opting to leave their lights off all weekend long, or install motion sensitive lights to conserve energy, plants that enjoy 7 day per week light are adapting to far less light per week. While Devil’s Ivy is not damaged by less light, if the color change bothers you it may be time to move the plant to a location underneath an emergency light that is on 24 hours per day – 7 days per week, or nearer a window.
It may take a few months, but with a little more light, your plant will return it’s leaf pattern to what it was when you purchased it.
Furry white mold and mildew can appear on your houseplants or on top of your potting soil if the conditions the plants are kept in are too warm and moist. To control the growth of fungus on your houseplants you must first change the conditions of the environment that you keep the plants in. Move the plants to a new location that is not as moist, or consider whether you are watering your plants too much. Constantly saturated soil or moist soil is the perfect environment for fungal growth.
To kill and eliminate the mildew already on the topsoil, a light dusting of a drugstore Athlete’s Foot powder will manage the problem for you. Once you have removed the environmental triggers of the fungus growth, and killed the spores, you should have a completely clean container within two weeks.
Looking for more indoor plant care tips? Check out the book “Success With Houseplants.”
Photo Courtesy of: psyberartist
One particularly common garden pest wreaking havoc on shrubs in the months of May through August is ‘Armor Scale’, also called ‘Oyster Shell Scale,’ or ‘Wax Scale.’
Identification:
Oyster Shell Scale is a peculiar looking insect, who becomes obvious on your shrubs only after it has begun to create a protective covering over itself. The shell that an active Scale creates can resemble anything from a wad of chewed gum, to a fuzzy ball on the stems and leaves of woody plants. The white waxy ’shell’ covering is pliable in early summer months, and emits Honeydew that the insect excretes as it feeds on the sap of a plant. Aged Scale, and dead Scale that have completed their life cycle are dry, hard, and a grey or brown color. They begin to resemble bark before they fall off a plant, but can be pruned out for appearance sake.
Scale are sucking insects, and they and their offspring (called ‘crawlers’) attach themselves to a plant within a few hours of hatching, remaining stationary for the remainder of their life while receiving the nutrients they need from sap. Female Scale lay eggs inside of their shell, and the ‘crawlers’ emerge in late April or May to wander the plant for a one or two week window in search of a good permanent place for themselves.
While scale in small numbers are not harmful, in large numbers they can kill a plant in several ways. Large clusters of scale will rob a plant of it’s nutrients, and stop leaf production, killing sections of a plant. Additionally, the sugary Honeydew residue can become a breeding ground for black powdery mold and bacteria, which are deadly to a plant when left unpruned. Heavy Bee and Ant activity around infested plants can be the first indicator of a Scale problem, as the two species are attracted to the Honeydew as an alternate food source. (more…)
Looking over some garden hedges recently, I discovered a type of gall on all six of the identical shrubs. The gall growths were hard, irregularly shaped, and about two inches in diameter. I looked over the area that the galls were attached to, and noticed that the galls were mostly growing in areas that had been pruned within the last one or two years, a sign that pointed to a bacterial gall instead of an insect gall. I snapped the gall off of the plant to have a closer look.
There are many types of gall with several specific causes, but they can generally be broken down into two categories: disease caused, and insect caused. Insect caused galls come in all shapes and sizes, both soft tissue growths, fuzzy growths, and firm growths. All of them hold either the eggs or larvae of a specific type of wasp or mite inside, and can contain hollow areas inside the gall where the creature lives and feeds. Insect caused galls may look strange and detract from the outward appearance of a plant, but they do not damage plants. Disease galls do damage a plant, and are initially caused by a bacterium that lives in the soil, although they are commonly spread from plant to plant by pruning, or grafting, when hedge shears have come into contact with an infected plant. The true damage caused by a bacterial gall is actually in and around the gall growth, where the unchecked growth of cell tissue distorts, or chokes off the flow of water and nutrients through the plant.
How To Discern Between Insect And Disease Caused Galls:
With the above pictured gall, I investigated the cause of the growth visually from the exterior appearance, and by dissecting the growth, to check for hollow areas inside the gall that would be a sign of insects. I found that the gall was solid throughout, with layers of disorganized tissue, and concluded that the gall was in fact Crown Gall, a bacterial infection. If you find a gall on one of your plants you will need to do these two things to determine the root cause. Identifying the shape of a gall is important, the shape and appearance of a gall can most often tell you what the root cause is. If you are unsure, or just curious, you can then dissect the gall to check the inside for insect life.
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Unfortunately even our home or office plants can become prone to diseases, no matter how great a life we try and provide for them. Often a disease can be an indicator of another problem altogether in a plant.
This mold spot developed on the leaves of a friends Lucky Bamboo, after weeks of yellowing leaves on the previously healthy plant. My friend was at a loss as to what to do with it, and set the bamboo outside on her patio for the last months of the summer in the hopes that the yellowing leaves on the plant were due to a curable lack of sunlight. Unfortunately, the yellowing leaves quickly gave bloom to black mold spots, a condition that seemed peculiar in the plants dry location. Not knowing what was wrong with her Lucky Bamboo, or if it was salvageble, she was prepared to throw the plant out and start over fresh, so I looked the plant over from top to bottom to find the problem.
Mold spores are one of many living organisms that are always present in the air, and that thrive in outdoor gardens, regardless of whether you ever see any signs of them on other plants. They are also a opportunistic, and will take advantage of a plant that is suffering under other issues, as was the case with this particular plant. Here is one of the problems, many Lucky Bamboo plants are advertised as being a no-maintenance home or office plant, capable of living in a small container with no food source needed other than tap water. Over time however, many of these plants begin to develop yellowing leaves, and mold spots like this, due to a lack of several things. Lucky Bamboo, like all plants needs water, and a reliable source of nutrients. Mere tap water cannot meet their needs over time, and the plant actually need a reliable source of nutrition, whether they live in a glass of water, and recieve bi-monthly liquid fertilizers, or they are potted, and a give granular, or time release fertilizer. The second problem with this plant was that after several years, this plant had outgrown its pot, and was what is known as “pot bound.” A pot bound plant has a root system that has outgrown it’s container. The roots of this Bamboo plant continued to grow naturally, as the plant seeks out more water and nutrients to feed the stems and leaves of the plant, but in a small container, the root system wraps around itself repeatedly with no where to go, and can kill itself if left alone.
In this case, the root bound plant was under stress in these cramped quarters, and responded by displaying limp and light yellow leaves. When a plant is unable to take care of all of it’s foliage, it often begins to slowly shut down, letting leaves die, and fall off. The yellowing leaves, and the weakened plant are then susceptible to other diseases, which in this case led to the plants current issue with black mold spots.
What To Look For In Cases Of Black Mold Spots In Home And Office Plants:
- Over watered plants and wet soil
- Poor drainage in the potting container
- Overcrowded plant life
- Pot-bound root systems
- Poor fertilization, or a lack of fertilization
- A home or office environment prone to high humidity and warm temperatures
What To Do With Plants Displaying Moldy Leaves:
- Trim off any branches that are infected, and discard.
Almost any plant can be saved from mold if you catch the problem before most of the foliage is gone, discover the source of the problem, and find a remedy. In the case of a root bound pot, the root system will be loosened and trimmed, and the plant will be repotted in a larger container with fertilizer. The moldy foliage will be trimmed off, and the plant will rebound over a few months, and send out new growth.
Can plants get sunburn? The answer is yes! Most plants are not susceptible to sun damage, but many common home and office plants can suffer from sunburn because they are specifically suited to shadier locations – a leading reason they have earned a place in artificially lit environments.
Pictured here are a few leaves on a Chinese Evergreen (Aglaonema modestum) plant, that was accidentally left outdoors on a sunny ledge during an office cleaning spree. The plant was brought back indoors two days after it was set outside, and was already showing signs of burn damage.
How can you tell if leaf damage is sun related?
- The most immediate symptom displayed by a sun damaged plant is muted leaf color, and an overall greyish tone to the previously green plant.
- There will be an obvious difference in color between the leaves exposed to more light on the top of the plant, and the leaves deeper into the interior of the plant, which have been kept shaded. Yellowing will occur in the leaves that follows straight lines, such as above, denoting the areas of the plant that have been shaded by overlapping leaves. Unlike fertilizer burn, and plants suffering from a lack of water, which display irregular yellowing patterns (developing at the tips of the leaves), this yellowing does not turn into brown leaves that curl, or dry up.
- Burned leaves remain on the plant looking off color, or yellowed slightly, without falling off. Often the color of the burned area will soften to a transparent hue, where you will be able to see through the leaf, or the leaf will develop irregular bumps on the yellowing area that will look much like a reaction to sun-poisoning in people.
What to do with sun-damaged plants:
- Place the plant in an area away from direct sunlight, drafts, and excessive heat.
- Water the plant to keep the soil moist, but not wet.
- Monitor the amount of leaves damaged by the sun, and remove burned leaves by pruning back. I generally prune off the leaves in groups over a gradual period of time (several days to weeks), to give a plant that may have a serious case of sunburn a chance to send out new leaves to take over the photosynthesizing, since a badly damaged plant may need most of it’s leaves eventually trimmed off. Trimming all the damaged leaves at once could place the plant into additional shock.
Remember, any shade loving plant can suffer from sunburn, it’s what you do with the plant afterward that will assure the plant’s full recovery. Err on the side of caution with office plants, when exposing them to direct sunlight, and you may be able to prevent problems like this from ever occurring with your green office companions.
Your thoughts: Have you had plants with sun damage? What tips and tricks have you tried to bring them back to health? Please share any ideas you have with everyone!
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