A plant’s foliage is often one of the first ways we can tell if that plant is happy, healthy, and thriving. From purchasing a plant at the garden center to keeping it happy in your garden, here are some timely tips on how to understand what your foliage is communicating to you. Still confused or in doubt after reading this article?
Take a picture or a clipping of your plant leaf problem and bring it into your trusted local garden center or county extension office — they can usually help you diagnose the particular problem and give you suggestions on an appropriate remedy.
What Do Healthy Plant Leaves Look Like?
While it might be stating the obvious, it’s crucially important to understand what your plants’ leaves should look like so you’re better able to observe when things go amiss. And while all plants have different growth patterns and characteristics, healthy leaves usually have:
- Vigorous growth
- Uniform color (unless they are naturally variegated)
- Open, rather than curled, growth
- Upright appearance
Tip: Remember to look at the underside of your plants’ leaves as well — many damaging insects hide in those hard-to-see places.
Signs of Poor Leaf Health
- Wilting: Wilting is a strong signal that the plant is either thirsty or overheated. If you live in a very warm climate, afternoon wilting is somewhat common and to be expected, but if the wilting continues into the next morning, water ASAP. Feel like you’re watering all the time and you’re still seeing wilting? You may not be watering deeply enough. Most plants prefer less frequent but more deep watering to remain hydrated.
- Brown tips: This is usually a sign of underwatering, so plan to increase your watering frequency or the depth to which you are watering. Those brown tips will not regenerate and become green again — snip off the unsightly ends or, if most of the leaf is brown and crunchy, remove the entire leaf.
- White powdery leaf surface: Powdery mildew is easily diagnosed, and usually occurs on new growth during periods of high humidity. Planting too close together also decreases ventilation between plants, which can lead to powdery mildew. Leave plenty of room between plants, watch out for water on the leaves, and use an organic fungicide to treat and stop the spread.
- Tiny pale spots or webbing on leaves: Spider mites are spider relatives that suck out plant fluids through the leaves, often leaving a pale webbing in the process. Isolate the plant if you can, and use an organic insecticidal spray like neem oil to control the infestation.
- Silver or bronze colored streaks: Ahhh, those pesky thrips. These tiny insects puncture holes in the leaves and suck out the sap, leaving unattractive streaks on the leaf surface. Use an organic insecticide like neem oil when you first detect the issue, then repeat at 7- to 10-day intervals.
Yellow & Curled Leaves
- Yellow lower leaves: This could be a possible nitrogen deficiency. If the plant is nitrogen deficient, it will pull available nitrogen from the older, lower leaves to give it to the new leaves. Give your plant a high nitrogen fertilizer during the leaf growth stage — when it’s in the bloom stage, however, you’ll want a low nitrogen fertilizer.
- Curled leaves: Leaves that curl inward could have heat stress. Provide some overhead shade with a shade cloth, give your plant a drink of cool water, or move it away from a light source if it’s a potted plant.
- Yellow spots: Could be aphids! These annoying bugs suck the life out of your leaves, leaving yellow spots and causing wilting. They congregate on the underside of your leaves, so be sure to look for them there. Use an organic insecticidal soap to control.