Seeing your daylily leaves turn yellow can be worrying. You’ve invested time and care into these perennials, and this change signals something is off. This guide will help you figure out why are my daylily leaves turning yellow and what you can do about it. Let’s look at the common causes, from simple fixes to more serious issues, so you can restore your plants to health.
Daylilies (Hemerocallis) are famously tough, but they’re not invincible. Yellowing leaves, or chlorosis, is a symptom, not a disease itself. It’s the plant’s way of telling you it’s stressed. The good news is that most problems are solvable with a little detective work and some simple garden care adjustments.
Why Are My Daylily Leaves Turning Yellow
The reasons for yellow leaves range from natural processes to pests and cultural mistakes. We’ll break them down from most to least common, starting with the easiest to fix.
Natural Aging and Seasonal Cycle
First, don’t panic. Sometimes, yellowing is perfectly normal.
* Older Foliage Die-Back: Individual leaves, especially the outer, older ones, naturally yellow and die as the plant directs energy to new growth and bloom production. This is normal throughout the growing season.
* Seasonal Dormancy: For many daylily varieties, the entire clump’s foliage turns yellow and brown after the first hard frost in fall. The plant is entering its dormant period. This is expected and healthy.
What to do: If only a few outer leaves are yellow while the rest of the plant looks vigorous, simply snip them off at the base with clean shears. For fall die-back, you can cut the entire clump back to a few inches above the ground after it has yellowed.
Watering Issues: Too Much or Too Little
Incorrect watering is perhaps the most frequent cause of stress-related yellowing. Daylilies prefer consistent moisture but despise soggy feet.
Overwatering and Poor Drainage:
Soggy soil suffocates roots, preventing them from taking up nutrients. This leads to yellow, often limp leaves. If the crown (where leaves meet roots) feels mushy, root rot has likely set in.
Underwatering and Drought Stress:
While drought-tolerant, extended dry periods cause leaves to yellow, starting at the tips and margins, before turning brown and crispy.
How to Check:
Stick your finger 2-3 inches into the soil near the plant. It should feel like a wrung-out sponge—moist but not wet. If it’s sopping wet or bone dry, you’ve found the likely culprit.
Nutrient Deficiencies in the Soil
Daylilies aren’t heavy feeders, but they do need some key nutrients. A lack of these can cause yellowing patterns.
* Nitrogen Deficiency: This is the most common nutrient issue. Nitrogen is mobile in the plant, so the older, lower leaves turn pale yellow first while new growth may remain green.
Iron Deficiency: Often occurs in high-pH (alkaline) soils. Iron is immobile, so the newest leaves at the center of the fan show yellowing between dark green veins.
* General Hunger: Plants growing in very poor, sandy, or depleted soil may simply need a balanced meal.
A simple soil test from your local extension service can confirm deficiencies. It’s the best way to know for sure what your soil lacks.
Pests and Diseases
While generally pest-resistant, daylilies can fall prey to a few specific problems.
Daylily Leaf Streak
This fungal disease is very common. It starts as yellow streaks along the leaf midrib, which then turn brown. Leaves may yellow and die back from the tips.
Spider Mites
These tiny pests suck sap from leaves, causing a stippled, yellowish appearance. You might see fine webbing on the undersides of leaves, especially in hot, dry weather.
Thrips
They rasp leaf surfaces, leading to silvery or yellowish streaks and distorted growth.
Root-Knot Nematodes
These microscopic worms attack roots, causing galls (swellings). The plant becomes stunted, and leaves yellow and wilt because the damaged roots can’t function properly.
Crowding and Competition
A mature daylily clump can become too dense over 4-5 years. Crowded plants compete fiercely for water, nutrients, and light. The center of the clump may yellow and die out as a result. This is a clear sign it’s time to divide.
Planting Depth and Physical Damage
If the crown (the white part between leaves and roots) is buried too deep, it can rot, causing the entire fan to yellow and collapse. Conversely, if roots are too shallow, they dry out quickly. Also, damage from string trimmers or garden tools can injure the crown or leaves, leading to localized yellowing.
Environmental and Chemical Stress
* Herbicide Drift: Accidental exposure to weed killers, even from a neighbor’s yard, can cause bizarre yellowing, twisting, or stunting of leaves.
* Extreme Weather: A sudden, severe heatwave or an unexpected late frost can shock plants, resulting in yellow foliage.
Step-by-Step Troubleshooting Guide
Follow this systematic approach to diagnose your yellowing daylilies.
1. Observe the Pattern. Look closely. Is the yellowing on old leaves or new growth? Is it uniform, streaked, or at the leaf edges? Are whole fans yellow or just scattered leaves? This is your first clue.
2. Check the Soil Moisture. Do the finger test. Is the soil waterlogged or parched? Examine the planting site’s drainage—does water pool there after rain?
3. Inspect for Pests and Disease. Turn leaves over and look closely for tiny moving dots (mites, thrips) or webbing. Look for brown streaks or spots that follow leaf veins.
4. Consider the Plant’s Age and Location. How long has the clump been in place? Is it shaded by larger plants now? Has anything changed in its environment?
5. Review Your Care Routine. Have you fertilized recently? Has weather been extreme? Have any chemicals been used nearby?
6. Dig Gently (if needed). If you suspect crown rot or nematodes, carefully dig beside the plant. Check the crown’s firmness and look for swollen, knobby roots.
Solutions and Preventative Care
Once you’ve identified the likely cause, here’s how to respond.
Correcting Watering Problems
* For Overwatering: Improve drainage. Amend clay soil with compost. Consider relocating the plant to a raised bed or slope. Reduce watering frequency.
* For Underwatering: Water deeply and thoroughly, ensuring moisture reaches the root zone (about 8 inches deep). Apply a 2-3 inch layer of organic mulch (like shredded bark) around, not on, the crown to retain soil moisture.
Fixing Nutrient Problems
* For a nitrogen boost, apply a balanced, slow-release fertilizer (like a 10-10-10) in early spring as growth emerges. A side-dressing of compost works wonderfully too.
* For suspected iron deficiency, a foliar spray of chelated iron can green up new growth quickly, but long-term adjustment of soil pH may be needed.
* The best prevention is to incorporate compost into the soil annually and use a balanced fertilizer modestly. More is not better with daylilies.
Managing Pests and Disease
* For Leaf Streak: Practice good sanitation. Remove and destroy all infected foliage in fall. Improve air flow by dividing crowded plants. In severe cases, a fungicide labeled for daylilies can be used in early spring.
* For Spider Mites and Thrips: A strong blast of water from the hose can dislodge many pests. For persistent issues, use insecticidal soap or horticultural oil, covering leaf undersides thoroughly.
* For Nematodes: This is tough. Remove and destroy severely infected plants. Solarize the soil before replanting, or choose nematode-resistant varieties for that area.
Dividing Overcrowded Clumps
The best time to divide is in early spring or just after flowering in late summer.
* Dig up the entire clump.
* Wash off soil so you can see the roots and fans.
* Gently pull or cut apart the clump into smaller divisions, each with at least 3 fans and healthy roots.
* Replant at the proper depth (crown no more than 1 inch below soil level) in amended soil, and water well.
FAQ Section
Should I cut yellow leaves off daylilies?
Yes, it’s a good idea. Remove yellow or brown leaves at the base to improve appearance and reduce hiding places for pests and disease spores. Use clean, sharp tools.
Can yellow daylily leaves turn green again?
Once a leaf turns yellow, it will not regain its green color. The goal is to correct the problem so that new growth emerges healthy and green.
Is it normal for daylilies to turn yellow in summer?
Some yellowing of older leaves is normal. But widespread yellowing during summer heat often indicates drought stress or spider mite activity, both of which should be addressed.
How often should daylilies be watered?
There’s no universal schedule. Water deeply when the top few inches of soil become dry. Established plants in good soil may need only weekly watering, while new plantings or those in sandy soil may need water more frequently.
What is the best fertilizer for preventing yellow leaves?
A balanced, slow-release granular fertilizer applied in early spring, coupled with a yearly top-dressing of compost, provides steady nutrition and improves soil health, preventing many deficiency issues.
When should I worry about yellow leaves?
Worry when yellowing is rapid, affects new growth, is accompanied by streaking or stunting, or when entire fans are collapsing. Isolated, old leaves yellowing is typically not a concern.
By working through these steps, you can usually pinpoint why your daylily leaves are changing color. Remember, gardening is about observation and response. With the right care, your daylilies will reward you with vibrant greenery and plenty of beautiful blooms for seasons to come.