Do not be alarmed if you see my older, outer leaves beginning to yellow and fade, typically in the late summer or early fall. This is a natural and necessary part of my life cycle. As a perennial plant, I must redirect my energy and nutrients—particularly nitrogen—away from these mature leaves and back into my crown and root system. This stored energy is crucial for my survival through the winter and will fuel the vibrant new growth you will see emerge next spring. Simply trim these spent leaves away to keep me looking tidy.
My roots require oxygen as much as they require water. When I am planted in heavy, compacted soil or a location with poor drainage, or if I am given too much water, my roots begin to suffocate. This waterlogged environment prevents them from absorbing essential nutrients and, critically, from performing respiration. The result is root rot, a condition where my roots turn brown, mushy, and die. Without a healthy root system, I cannot uptake water or nutrients, and my leaves will signal this distress by turning yellow, often starting with the lower leaves and feeling soft and limp.
Conversely, a prolonged lack of moisture will also cause my leaves to yellow. As a shade-loving plant, I have broad leaves that lose water readily through transpiration. If I do not receive consistent moisture, especially during hot, dry periods, I become stressed and cannot move nutrients effectively throughout my system. The yellowing from underwatering is often accompanied by browning, crispy leaf edges and may cause leaves to droop or wilt before they change color.
The rich green color of my foliage is directly linked to chlorophyll, which requires sufficient nitrogen. If I am growing in nutrient-poor soil or have been in the same location for many years without supplemental feeding, I may develop a nitrogen deficiency. This typically manifests as an overall light green or yellowing of the leaves, particularly in the older leaves first, as I move the limited nitrogen to support new growth. An imbalance in other nutrients can also cause chlorosis, or yellowing, between the leaf veins.
While some of my cousins can tolerate more sun, most of us hostas thrive in partial to full shade. When planted in a location with too much direct, intense sunlight—especially the hot afternoon sun—my large leaves can literally get sunburned. This sun scorch damages the chlorophyll, causing the leaves to turn yellow or a pale, washed-out green, often with brown, scorched tips and margins. The leaves facing the sun will show the most damage.
My succulent roots are a favorite meal for voles and nematodes. These pests feeding underground damage my root system, disrupting my ability to take up water and nutrients. The damage is often localized at first; you may see a single clump within a larger plant yellowing and wilting while the rest of me appears fine. If you suspect pests, gently dig around my base to inspect the roots for chew marks or the presence of the grubs themselves.
Fungal diseases like Fusarium root and crown rot or Southern blight (Sclerotium rolfsii) can attack me, especially in warm, wet conditions. These pathogens infect my crown and root system, causing it to decay. The tell-tale sign is a rapid yellowing and wilting of the leaves, often followed by a collapse of the entire plant. You might also see white fungal growth (mycelium) or brown, mustard-seed-like sclerotia at my base if Southern blight is the culprit.
