Diagnosis of 7 Common Plant Issues

Keeping our plants healthy through heat and rain can take a bit of work and TLC. After all your time and effort, it may be discouraging when you notice your plants looking unhealthy. Identifying some of the common plant issues can be difficult, but we have rounded up symptoms of stress, disease, and insect infestation to help you determine what is affecting your plants.

Common Plant Issues – and What to Do About Them

1. Yellowing leaves are a common sign of distress in plants. If the yellowing is patchy–only affecting some of the leaves–your plant likely needs some watering or sunlight. Adjust the conditions and give the plant a little extra care to bring it back to full health. However, if the entire plant has a yellow hue, this is a sign of a nutrient deficiency. Apply fertilizer or plant food and you should see a return to normalcy within a few days.
2. Black residue on leaves are the result of mold growing on insect droppings. This is a common sign of infestation of sucking insects like aphids, mealybug, and white fly. Insecticides such as neem oil will help eliminate the insects causing the mold.
3. Brown spots on the tops of leaves can be a sign of sun scald resulting from too much direct sun exposure. If possible, move the plant or provide shade during the hottest times of the afternoon. When the spots go all the way through the leaf, this indicates fungal disease and should be treated with a topical fungicide.
4. Curling leaves are a common sign of a sucking insect infestation–mites, scale, aphids, and mealybugs will all cause this appearance. A neem oil or other insecticide will get rid of the pests.
5. Distorted leaves may indicate a phosphorus or potassium deficiency. A purple-ish tinge on the bottom of older leaves points to phosphorus as the deficient nutrient, while brown or yellow coloring along the margins of leaves and “scorching” along the main veins are symptoms of a lack of potassium. Potassium deficiencies are common on sandy soils like ours, so keep these symptoms in mind. Applying a phosphate fertilizer or materials like bone meal or manure will increase phosphorus levels, while a potash fertilizer or compost from food scraps (especially banana peels) will bring up your soil’s potassium levels.
6. Stunted growth can occur when plants are installed too deeply or if mulch is stacked up against the trunk. If your plant is not getting taller, make sure the soil covers the roots without piling against the main stem or trunk. For mulched plants, lay the mulch in a donut shape around the plant, with about 8” of bare soil around the trunk. If you notice that leaves and twigs are smaller than usual, your plant may be experiencing a nitrogen deficiency. You will also see the leaves have a light green to yellow coloration.
7. Blooming is not a guaranteed occurrence; many plants go through a bloom cycle and thus will not flower every year. However, a lack of sunlight will prevent a plant from blooming even if it is the right season. Make sure your plant is getting its required amount of sunlight, and if you are particularly concerned, apply a fertilizer with a high amount of phosphorus.

Green or gray growth on the bark is called lichen, and it is nothing to worry about! Lichen are beneficial and harmless to your plants.

If you need fertilizer, mulch, or anything else to help you in combatting these common plant issues, check our the online store at Big Earth Landscaping Supply.